[for-next][PATCH 00/30] tracing: Updates for the next merge window

[for-next][PATCH 00/30] tracing: Updates for the next merge window

[Steven Rostedt]

Note, I still have more in my queue that need to go through testing.

  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
for-next

Head SHA1: e007f5165a2e366579324062a69e56236a97fad3


Dan Carpenter (1):
      tracing: Have trace_stack nr_entries compare not be so subtle

Joe Lawrence (1):
      scripts/recordmcount.{c,pl}: support -ffunction-sections .text.* section names

Masami Hiramatsu (11):
      tracing/uprobes: Add busy check when cleanup all uprobes
      tracing: Lock event_mutex before synth_event_mutex
      tracing: Simplify creation and deletion of synthetic events
      tracing: Integrate similar probe argument parsers
      tracing: Add unified dynamic event framework
      tracing/kprobes: Use dyn_event framework for kprobe events
      tracing/uprobes: Use dyn_event framework for uprobe events
      tracing: Use dyn_event framework for synthetic events
      tracing: Remove unneeded synth_event_mutex
      tracing: Add generic event-name based remove event method
      selftests/ftrace: Add testcases for dynamic event

Steven Rostedt (VMware) (17):
      function_graph: Remove unused task_curr_ret_stack()
      tracing: Do not line wrap short line in function_graph_enter()
      fgraph: Create a fgraph.c file to store function graph infrastructure
      fgraph: Have set_graph_notrace only affect function_graph tracer
      arm64: function_graph: Remove use of FTRACE_NOTRACE_DEPTH
      function_graph: Remove the use of FTRACE_NOTRACE_DEPTH
      ftrace: Create new ftrace_internal.h header
      function_graph: Do not expose the graph_time option when profiler is not configured
      fgraph: Move function graph specific code into fgraph.c
      tracing: Rearrange functions in trace_sched_wakeup.c
      fgraph: Add new fgraph_ops structure to enable function graph hooks
      function_graph: Move ftrace_graph_ret_addr() to fgraph.c
      function_graph: Have profiler use new helper ftrace_graph_get_ret_stack()
      ring-buffer: Add percentage of ring buffer full to wake up reader
      tracing: Add tracefs file buffer_percentage
      tracing: Change default buffer_percent to 50
      tracing: Consolidate trace_add/remove_event_call back to the nolock functions

----
 Documentation/trace/kprobetrace.rst                |   3 +
 Documentation/trace/uprobetracer.rst               |   4 +
 arch/arm64/kernel/stacktrace.c                     |   3 -
 include/linux/ftrace.h                             |  35 +-
 include/linux/ring_buffer.h                        |   4 +-
 kernel/trace/Kconfig                               |   6 +
 kernel/trace/Makefile                              |   2 +
 kernel/trace/fgraph.c                              | 615 +++++++++++++++++++++
 kernel/trace/ftrace.c                              | 471 ++--------------
 kernel/trace/ftrace_internal.h                     |  75 +++
 kernel/trace/ring_buffer.c                         |  94 +++-
 kernel/trace/trace.c                               |  72 ++-
 kernel/trace/trace.h                               |  13 +
 kernel/trace/trace_dynevent.c                      | 217 ++++++++
 kernel/trace/trace_dynevent.h                      | 119 ++++
 kernel/trace/trace_events.c                        |   8 +-
 kernel/trace/trace_events_hist.c                   | 316 ++++++-----
 kernel/trace/trace_functions_graph.c               | 334 ++---------
 kernel/trace/trace_irqsoff.c                       |  18 +-
 kernel/trace/trace_kprobe.c                        | 353 ++++++------
 kernel/trace/trace_probe.c                         |  74 ++-
 kernel/trace/trace_probe.h                         |   9 +-
 kernel/trace/trace_sched_wakeup.c                  | 270 +++++----
 kernel/trace/trace_selftest.c                      |   8 +-
 kernel/trace/trace_stack.c                         |   2 +-
 kernel/trace/trace_uprobe.c                        | 301 +++++-----
 scripts/recordmcount.c                             |   2 +-
 scripts/recordmcount.pl                            |  13 +
 .../ftrace/test.d/dynevent/add_remove_kprobe.tc    |  30 +
 .../ftrace/test.d/dynevent/add_remove_synth.tc     |  27 +
 .../ftrace/test.d/dynevent/clear_select_events.tc  |  50 ++
 .../ftrace/test.d/dynevent/generic_clear_event.tc  |  49 ++
 32 files changed, 2176 insertions(+), 1421 deletions(-)
 create mode 100644 kernel/trace/fgraph.c
 create mode 100644 kernel/trace/ftrace_internal.h
 create mode 100644 kernel/trace/trace_dynevent.c
 create mode 100644 kernel/trace/trace_dynevent.h
 create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/add_remove_kprobe.tc
 create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/add_remove_synth.tc
 create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/clear_select_events.tc
 create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/generic_clear_event.tc

[for-next][PATCH 01/30] function_graph: Remove unused task_curr_ret_stack()

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

The static inline function task_curr_ret_stack() is unused, remove it.

Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/linux/ftrace.h | 10 ----------
 1 file changed, 10 deletions(-)

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index dd16e8218db3..10bd46434908 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -809,11 +809,6 @@ extern void ftrace_graph_init_task(struct task_struct *t);
 extern void ftrace_graph_exit_task(struct task_struct *t);
 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
 
-static inline int task_curr_ret_stack(struct task_struct *t)
-{
-	return t->curr_ret_stack;
-}
-
 static inline void pause_graph_tracing(void)
 {
 	atomic_inc(&current->tracing_graph_pause);
@@ -838,11 +833,6 @@ static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 }
 static inline void unregister_ftrace_graph(void) { }
 
-static inline int task_curr_ret_stack(struct task_struct *tsk)
-{
-	return -1;
-}
-
 static inline unsigned long
 ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret,
 		      unsigned long *retp)
-- 
2.19.1

[for-next][PATCH 02/30] tracing: Do not line wrap short line in function_graph_enter()

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Commit 588ca1786f2dd ("function_graph: Use new curr_ret_depth to manage
depth instead of curr_ret_stack") removed a parameter from the call
ftrace_push_return_trace() that made it so that the entire call was under 80
characters, but it did not remove the line break. There's no reason to break
that line up, so make it a single line.

Link: http://lkml.kernel.org/r/20181122100322.GN2131@hirez.programming.kicks-ass.net

Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_functions_graph.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 086af4f5c3e8..0d235e44d08e 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -188,8 +188,7 @@ int function_graph_enter(unsigned long ret, unsigned long func,
 	trace.func = func;
 	trace.depth = ++current->curr_ret_depth;
 
-	if (ftrace_push_return_trace(ret, func,
-				     frame_pointer, retp))
+	if (ftrace_push_return_trace(ret, func, frame_pointer, retp))
 		goto out;
 
 	/* Only trace if the calling function expects to */
-- 
2.19.1

[for-next][PATCH 03/30] fgraph: Create a fgraph.c file to store function graph infrastructure

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

As the function graph infrastructure can be used by thing other than
tracing, moving the code to its own file out of the trace_functions_graph.c
code makes more sense.

The fgraph.c file will only contain the infrastructure required to hook into
functions and their return code.

Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/Makefile                |   1 +
 kernel/trace/fgraph.c                | 232 +++++++++++++++++++++++++++
 kernel/trace/trace_functions_graph.c | 220 -------------------------
 3 files changed, 233 insertions(+), 220 deletions(-)
 create mode 100644 kernel/trace/fgraph.c

diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index f81dadbc7c4a..c7ade7965464 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -57,6 +57,7 @@ obj-$(CONFIG_MMIOTRACE) += trace_mmiotrace.o
 obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += trace_functions_graph.o
 obj-$(CONFIG_TRACE_BRANCH_PROFILING) += trace_branch.o
 obj-$(CONFIG_BLK_DEV_IO_TRACE) += blktrace.o
+obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += fgraph.o
 ifeq ($(CONFIG_BLOCK),y)
 obj-$(CONFIG_EVENT_TRACING) += blktrace.o
 endif
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
new file mode 100644
index 000000000000..5ad9c0e88b80
--- /dev/null
+++ b/kernel/trace/fgraph.c
@@ -0,0 +1,232 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Infrastructure to took into function calls and returns.
+ * Copyright (c) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com>
+ * Mostly borrowed from function tracer which
+ * is Copyright (c) Steven Rostedt <srostedt@redhat.com>
+ *
+ * Highly modified by Steven Rostedt (VMware).
+ */
+#include <linux/ftrace.h>
+
+#include "trace.h"
+
+static bool kill_ftrace_graph;
+
+/**
+ * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called
+ *
+ * ftrace_graph_stop() is called when a severe error is detected in
+ * the function graph tracing. This function is called by the critical
+ * paths of function graph to keep those paths from doing any more harm.
+ */
+bool ftrace_graph_is_dead(void)
+{
+	return kill_ftrace_graph;
+}
+
+/**
+ * ftrace_graph_stop - set to permanently disable function graph tracincg
+ *
+ * In case of an error int function graph tracing, this is called
+ * to try to keep function graph tracing from causing any more harm.
+ * Usually this is pretty severe and this is called to try to at least
+ * get a warning out to the user.
+ */
+void ftrace_graph_stop(void)
+{
+	kill_ftrace_graph = true;
+}
+
+/* Add a function return address to the trace stack on thread info.*/
+static int
+ftrace_push_return_trace(unsigned long ret, unsigned long func,
+			 unsigned long frame_pointer, unsigned long *retp)
+{
+	unsigned long long calltime;
+	int index;
+
+	if (unlikely(ftrace_graph_is_dead()))
+		return -EBUSY;
+
+	if (!current->ret_stack)
+		return -EBUSY;
+
+	/*
+	 * We must make sure the ret_stack is tested before we read
+	 * anything else.
+	 */
+	smp_rmb();
+
+	/* The return trace stack is full */
+	if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
+		atomic_inc(&current->trace_overrun);
+		return -EBUSY;
+	}
+
+	/*
+	 * The curr_ret_stack is an index to ftrace return stack of
+	 * current task.  Its value should be in [0, FTRACE_RETFUNC_
+	 * DEPTH) when the function graph tracer is used.  To support
+	 * filtering out specific functions, it makes the index
+	 * negative by subtracting huge value (FTRACE_NOTRACE_DEPTH)
+	 * so when it sees a negative index the ftrace will ignore
+	 * the record.  And the index gets recovered when returning
+	 * from the filtered function by adding the FTRACE_NOTRACE_
+	 * DEPTH and then it'll continue to record functions normally.
+	 *
+	 * The curr_ret_stack is initialized to -1 and get increased
+	 * in this function.  So it can be less than -1 only if it was
+	 * filtered out via ftrace_graph_notrace_addr() which can be
+	 * set from set_graph_notrace file in tracefs by user.
+	 */
+	if (current->curr_ret_stack < -1)
+		return -EBUSY;
+
+	calltime = trace_clock_local();
+
+	index = ++current->curr_ret_stack;
+	if (ftrace_graph_notrace_addr(func))
+		current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH;
+	barrier();
+	current->ret_stack[index].ret = ret;
+	current->ret_stack[index].func = func;
+	current->ret_stack[index].calltime = calltime;
+#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
+	current->ret_stack[index].fp = frame_pointer;
+#endif
+#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
+	current->ret_stack[index].retp = retp;
+#endif
+	return 0;
+}
+
+int function_graph_enter(unsigned long ret, unsigned long func,
+			 unsigned long frame_pointer, unsigned long *retp)
+{
+	struct ftrace_graph_ent trace;
+
+	trace.func = func;
+	trace.depth = ++current->curr_ret_depth;
+
+	if (ftrace_push_return_trace(ret, func, frame_pointer, retp))
+		goto out;
+
+	/* Only trace if the calling function expects to */
+	if (!ftrace_graph_entry(&trace))
+		goto out_ret;
+
+	return 0;
+ out_ret:
+	current->curr_ret_stack--;
+ out:
+	current->curr_ret_depth--;
+	return -EBUSY;
+}
+
+/* Retrieve a function return address to the trace stack on thread info.*/
+static void
+ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
+			unsigned long frame_pointer)
+{
+	int index;
+
+	index = current->curr_ret_stack;
+
+	/*
+	 * A negative index here means that it's just returned from a
+	 * notrace'd function.  Recover index to get an original
+	 * return address.  See ftrace_push_return_trace().
+	 *
+	 * TODO: Need to check whether the stack gets corrupted.
+	 */
+	if (index < 0)
+		index += FTRACE_NOTRACE_DEPTH;
+
+	if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) {
+		ftrace_graph_stop();
+		WARN_ON(1);
+		/* Might as well panic, otherwise we have no where to go */
+		*ret = (unsigned long)panic;
+		return;
+	}
+
+#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
+	/*
+	 * The arch may choose to record the frame pointer used
+	 * and check it here to make sure that it is what we expect it
+	 * to be. If gcc does not set the place holder of the return
+	 * address in the frame pointer, and does a copy instead, then
+	 * the function graph trace will fail. This test detects this
+	 * case.
+	 *
+	 * Currently, x86_32 with optimize for size (-Os) makes the latest
+	 * gcc do the above.
+	 *
+	 * Note, -mfentry does not use frame pointers, and this test
+	 *  is not needed if CC_USING_FENTRY is set.
+	 */
+	if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
+		ftrace_graph_stop();
+		WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
+		     "  from func %ps return to %lx\n",
+		     current->ret_stack[index].fp,
+		     frame_pointer,
+		     (void *)current->ret_stack[index].func,
+		     current->ret_stack[index].ret);
+		*ret = (unsigned long)panic;
+		return;
+	}
+#endif
+
+	*ret = current->ret_stack[index].ret;
+	trace->func = current->ret_stack[index].func;
+	trace->calltime = current->ret_stack[index].calltime;
+	trace->overrun = atomic_read(&current->trace_overrun);
+	trace->depth = current->curr_ret_depth--;
+	/*
+	 * We still want to trace interrupts coming in if
+	 * max_depth is set to 1. Make sure the decrement is
+	 * seen before ftrace_graph_return.
+	 */
+	barrier();
+}
+
+/*
+ * Send the trace to the ring-buffer.
+ * @return the original return address.
+ */
+unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
+{
+	struct ftrace_graph_ret trace;
+	unsigned long ret;
+
+	ftrace_pop_return_trace(&trace, &ret, frame_pointer);
+	trace.rettime = trace_clock_local();
+	ftrace_graph_return(&trace);
+	/*
+	 * The ftrace_graph_return() may still access the current
+	 * ret_stack structure, we need to make sure the update of
+	 * curr_ret_stack is after that.
+	 */
+	barrier();
+	current->curr_ret_stack--;
+	/*
+	 * The curr_ret_stack can be less than -1 only if it was
+	 * filtered out and it's about to return from the function.
+	 * Recover the index and continue to trace normal functions.
+	 */
+	if (current->curr_ret_stack < -1) {
+		current->curr_ret_stack += FTRACE_NOTRACE_DEPTH;
+		return ret;
+	}
+
+	if (unlikely(!ret)) {
+		ftrace_graph_stop();
+		WARN_ON(1);
+		/* Might as well panic. What else to do? */
+		ret = (unsigned long)panic;
+	}
+
+	return ret;
+}
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 0d235e44d08e..b846d82c2f95 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -16,33 +16,6 @@
 #include "trace.h"
 #include "trace_output.h"
 
-static bool kill_ftrace_graph;
-
-/**
- * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called
- *
- * ftrace_graph_stop() is called when a severe error is detected in
- * the function graph tracing. This function is called by the critical
- * paths of function graph to keep those paths from doing any more harm.
- */
-bool ftrace_graph_is_dead(void)
-{
-	return kill_ftrace_graph;
-}
-
-/**
- * ftrace_graph_stop - set to permanently disable function graph tracincg
- *
- * In case of an error int function graph tracing, this is called
- * to try to keep function graph tracing from causing any more harm.
- * Usually this is pretty severe and this is called to try to at least
- * get a warning out to the user.
- */
-void ftrace_graph_stop(void)
-{
-	kill_ftrace_graph = true;
-}
-
 /* When set, irq functions will be ignored */
 static int ftrace_graph_skip_irqs;
 
@@ -117,199 +90,6 @@ static void
 print_graph_duration(struct trace_array *tr, unsigned long long duration,
 		     struct trace_seq *s, u32 flags);
 
-/* Add a function return address to the trace stack on thread info.*/
-static int
-ftrace_push_return_trace(unsigned long ret, unsigned long func,
-			 unsigned long frame_pointer, unsigned long *retp)
-{
-	unsigned long long calltime;
-	int index;
-
-	if (unlikely(ftrace_graph_is_dead()))
-		return -EBUSY;
-
-	if (!current->ret_stack)
-		return -EBUSY;
-
-	/*
-	 * We must make sure the ret_stack is tested before we read
-	 * anything else.
-	 */
-	smp_rmb();
-
-	/* The return trace stack is full */
-	if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
-		atomic_inc(&current->trace_overrun);
-		return -EBUSY;
-	}
-
-	/*
-	 * The curr_ret_stack is an index to ftrace return stack of
-	 * current task.  Its value should be in [0, FTRACE_RETFUNC_
-	 * DEPTH) when the function graph tracer is used.  To support
-	 * filtering out specific functions, it makes the index
-	 * negative by subtracting huge value (FTRACE_NOTRACE_DEPTH)
-	 * so when it sees a negative index the ftrace will ignore
-	 * the record.  And the index gets recovered when returning
-	 * from the filtered function by adding the FTRACE_NOTRACE_
-	 * DEPTH and then it'll continue to record functions normally.
-	 *
-	 * The curr_ret_stack is initialized to -1 and get increased
-	 * in this function.  So it can be less than -1 only if it was
-	 * filtered out via ftrace_graph_notrace_addr() which can be
-	 * set from set_graph_notrace file in tracefs by user.
-	 */
-	if (current->curr_ret_stack < -1)
-		return -EBUSY;
-
-	calltime = trace_clock_local();
-
-	index = ++current->curr_ret_stack;
-	if (ftrace_graph_notrace_addr(func))
-		current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH;
-	barrier();
-	current->ret_stack[index].ret = ret;
-	current->ret_stack[index].func = func;
-	current->ret_stack[index].calltime = calltime;
-#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
-	current->ret_stack[index].fp = frame_pointer;
-#endif
-#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
-	current->ret_stack[index].retp = retp;
-#endif
-	return 0;
-}
-
-int function_graph_enter(unsigned long ret, unsigned long func,
-			 unsigned long frame_pointer, unsigned long *retp)
-{
-	struct ftrace_graph_ent trace;
-
-	trace.func = func;
-	trace.depth = ++current->curr_ret_depth;
-
-	if (ftrace_push_return_trace(ret, func, frame_pointer, retp))
-		goto out;
-
-	/* Only trace if the calling function expects to */
-	if (!ftrace_graph_entry(&trace))
-		goto out_ret;
-
-	return 0;
- out_ret:
-	current->curr_ret_stack--;
- out:
-	current->curr_ret_depth--;
-	return -EBUSY;
-}
-
-/* Retrieve a function return address to the trace stack on thread info.*/
-static void
-ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
-			unsigned long frame_pointer)
-{
-	int index;
-
-	index = current->curr_ret_stack;
-
-	/*
-	 * A negative index here means that it's just returned from a
-	 * notrace'd function.  Recover index to get an original
-	 * return address.  See ftrace_push_return_trace().
-	 *
-	 * TODO: Need to check whether the stack gets corrupted.
-	 */
-	if (index < 0)
-		index += FTRACE_NOTRACE_DEPTH;
-
-	if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) {
-		ftrace_graph_stop();
-		WARN_ON(1);
-		/* Might as well panic, otherwise we have no where to go */
-		*ret = (unsigned long)panic;
-		return;
-	}
-
-#ifdef HAVE_FUNCTION_GRAPH_FP_TEST
-	/*
-	 * The arch may choose to record the frame pointer used
-	 * and check it here to make sure that it is what we expect it
-	 * to be. If gcc does not set the place holder of the return
-	 * address in the frame pointer, and does a copy instead, then
-	 * the function graph trace will fail. This test detects this
-	 * case.
-	 *
-	 * Currently, x86_32 with optimize for size (-Os) makes the latest
-	 * gcc do the above.
-	 *
-	 * Note, -mfentry does not use frame pointers, and this test
-	 *  is not needed if CC_USING_FENTRY is set.
-	 */
-	if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
-		ftrace_graph_stop();
-		WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
-		     "  from func %ps return to %lx\n",
-		     current->ret_stack[index].fp,
-		     frame_pointer,
-		     (void *)current->ret_stack[index].func,
-		     current->ret_stack[index].ret);
-		*ret = (unsigned long)panic;
-		return;
-	}
-#endif
-
-	*ret = current->ret_stack[index].ret;
-	trace->func = current->ret_stack[index].func;
-	trace->calltime = current->ret_stack[index].calltime;
-	trace->overrun = atomic_read(&current->trace_overrun);
-	trace->depth = current->curr_ret_depth--;
-	/*
-	 * We still want to trace interrupts coming in if
-	 * max_depth is set to 1. Make sure the decrement is
-	 * seen before ftrace_graph_return.
-	 */
-	barrier();
-}
-
-/*
- * Send the trace to the ring-buffer.
- * @return the original return address.
- */
-unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
-{
-	struct ftrace_graph_ret trace;
-	unsigned long ret;
-
-	ftrace_pop_return_trace(&trace, &ret, frame_pointer);
-	trace.rettime = trace_clock_local();
-	ftrace_graph_return(&trace);
-	/*
-	 * The ftrace_graph_return() may still access the current
-	 * ret_stack structure, we need to make sure the update of
-	 * curr_ret_stack is after that.
-	 */
-	barrier();
-	current->curr_ret_stack--;
-	/*
-	 * The curr_ret_stack can be less than -1 only if it was
-	 * filtered out and it's about to return from the function.
-	 * Recover the index and continue to trace normal functions.
-	 */
-	if (current->curr_ret_stack < -1) {
-		current->curr_ret_stack += FTRACE_NOTRACE_DEPTH;
-		return ret;
-	}
-
-	if (unlikely(!ret)) {
-		ftrace_graph_stop();
-		WARN_ON(1);
-		/* Might as well panic. What else to do? */
-		ret = (unsigned long)panic;
-	}
-
-	return ret;
-}
-
 /**
  * ftrace_graph_ret_addr - convert a potentially modified stack return address
  *			   to its original value
-- 
2.19.1

[for-next][PATCH 04/30] fgraph: Have set_graph_notrace only affect function_graph tracer

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

In order to make the function graph infrastructure more generic, there can
not be code specific for the function_graph tracer in the generic code. This
includes the set_graph_notrace logic, that stops all graph calls when a
function in the set_graph_notrace is hit.

By using the trace_recursion mask, we can use a bit in the current
task_struct to implement the notrace code, and move the logic out of
fgraph.c and into trace_functions_graph.c and keeps it affecting only the
tracer and not all call graph callbacks.

Acked-by: Namhyung Kim <namhyung@kernel.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/fgraph.c                | 21 ---------------------
 kernel/trace/trace.h                 |  7 +++++++
 kernel/trace/trace_functions_graph.c | 22 ++++++++++++++++++++++
 3 files changed, 29 insertions(+), 21 deletions(-)

diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index 5ad9c0e88b80..e852b69c0e64 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -64,30 +64,9 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func,
 		return -EBUSY;
 	}
 
-	/*
-	 * The curr_ret_stack is an index to ftrace return stack of
-	 * current task.  Its value should be in [0, FTRACE_RETFUNC_
-	 * DEPTH) when the function graph tracer is used.  To support
-	 * filtering out specific functions, it makes the index
-	 * negative by subtracting huge value (FTRACE_NOTRACE_DEPTH)
-	 * so when it sees a negative index the ftrace will ignore
-	 * the record.  And the index gets recovered when returning
-	 * from the filtered function by adding the FTRACE_NOTRACE_
-	 * DEPTH and then it'll continue to record functions normally.
-	 *
-	 * The curr_ret_stack is initialized to -1 and get increased
-	 * in this function.  So it can be less than -1 only if it was
-	 * filtered out via ftrace_graph_notrace_addr() which can be
-	 * set from set_graph_notrace file in tracefs by user.
-	 */
-	if (current->curr_ret_stack < -1)
-		return -EBUSY;
-
 	calltime = trace_clock_local();
 
 	index = ++current->curr_ret_stack;
-	if (ftrace_graph_notrace_addr(func))
-		current->curr_ret_stack -= FTRACE_NOTRACE_DEPTH;
 	barrier();
 	current->ret_stack[index].ret = ret;
 	current->ret_stack[index].func = func;
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 447bd96ee658..f67060a75f38 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -534,6 +534,13 @@ enum {
 
 	TRACE_GRAPH_DEPTH_START_BIT,
 	TRACE_GRAPH_DEPTH_END_BIT,
+
+	/*
+	 * To implement set_graph_notrace, if this bit is set, we ignore
+	 * function graph tracing of called functions, until the return
+	 * function is called to clear it.
+	 */
+	TRACE_GRAPH_NOTRACE_BIT,
 };
 
 #define trace_recursion_set(bit)	do { (current)->trace_recursion |= (1<<(bit)); } while (0)
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index b846d82c2f95..ecf543df943b 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -188,6 +188,18 @@ int trace_graph_entry(struct ftrace_graph_ent *trace)
 	int cpu;
 	int pc;
 
+	if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT))
+		return 0;
+
+	if (ftrace_graph_notrace_addr(trace->func)) {
+		trace_recursion_set(TRACE_GRAPH_NOTRACE_BIT);
+		/*
+		 * Need to return 1 to have the return called
+		 * that will clear the NOTRACE bit.
+		 */
+		return 1;
+	}
+
 	if (!ftrace_trace_task(tr))
 		return 0;
 
@@ -290,6 +302,11 @@ void trace_graph_return(struct ftrace_graph_ret *trace)
 
 	ftrace_graph_addr_finish(trace);
 
+	if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
+		trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
+		return;
+	}
+
 	local_irq_save(flags);
 	cpu = raw_smp_processor_id();
 	data = per_cpu_ptr(tr->trace_buffer.data, cpu);
@@ -315,6 +332,11 @@ static void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
 {
 	ftrace_graph_addr_finish(trace);
 
+	if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
+		trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
+		return;
+	}
+
 	if (tracing_thresh &&
 	    (trace->rettime - trace->calltime < tracing_thresh))
 		return;
-- 
2.19.1

[for-next][PATCH 05/30] arm64: function_graph: Remove use of FTRACE_NOTRACE_DEPTH

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Functions in the set_graph_notrace no longer subtract FTRACE_NOTRACE_DEPTH
from curr_ret_stack, as that is now implemented via the trace_recursion
flags. Access to curr_ret_stack no longer needs to worry about checking for
this. curr_ret_stack is still initialized to -1, when there's not a shadow
stack allocated.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 arch/arm64/kernel/stacktrace.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index 4989f7ea1e59..7723dadf25be 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -61,9 +61,6 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
 			(frame->pc == (unsigned long)return_to_handler)) {
 		if (WARN_ON_ONCE(frame->graph == -1))
 			return -EINVAL;
-		if (frame->graph < -1)
-			frame->graph += FTRACE_NOTRACE_DEPTH;
-
 		/*
 		 * This is a case where function graph tracer has
 		 * modified a return address (LR) in a stack frame
-- 
2.19.1

[for-next][PATCH 06/30] function_graph: Remove the use of FTRACE_NOTRACE_DEPTH

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

The curr_ret_stack is no longer set to a negative value when a function is
not to be traced by the function graph tracer. Remove the usage of
FTRACE_NOTRACE_DEPTH, as it is no longer needed.

Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/linux/ftrace.h               |  1 -
 kernel/trace/fgraph.c                | 19 -------------------
 kernel/trace/trace_functions_graph.c | 11 -----------
 3 files changed, 31 deletions(-)

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 10bd46434908..98625f10d982 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -790,7 +790,6 @@ unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
  */
 #define __notrace_funcgraph		notrace
 
-#define FTRACE_NOTRACE_DEPTH 65536
 #define FTRACE_RETFUNC_DEPTH 50
 #define FTRACE_RETSTACK_ALLOC_SIZE 32
 extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index e852b69c0e64..de887a983ac7 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -112,16 +112,6 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
 
 	index = current->curr_ret_stack;
 
-	/*
-	 * A negative index here means that it's just returned from a
-	 * notrace'd function.  Recover index to get an original
-	 * return address.  See ftrace_push_return_trace().
-	 *
-	 * TODO: Need to check whether the stack gets corrupted.
-	 */
-	if (index < 0)
-		index += FTRACE_NOTRACE_DEPTH;
-
 	if (unlikely(index < 0 || index >= FTRACE_RETFUNC_DEPTH)) {
 		ftrace_graph_stop();
 		WARN_ON(1);
@@ -190,15 +180,6 @@ unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
 	 */
 	barrier();
 	current->curr_ret_stack--;
-	/*
-	 * The curr_ret_stack can be less than -1 only if it was
-	 * filtered out and it's about to return from the function.
-	 * Recover the index and continue to trace normal functions.
-	 */
-	if (current->curr_ret_stack < -1) {
-		current->curr_ret_stack += FTRACE_NOTRACE_DEPTH;
-		return ret;
-	}
 
 	if (unlikely(!ret)) {
 		ftrace_graph_stop();
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index ecf543df943b..eaf9b1629956 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -115,9 +115,6 @@ unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
 	if (ret != (unsigned long)return_to_handler)
 		return ret;
 
-	if (index < -1)
-		index += FTRACE_NOTRACE_DEPTH;
-
 	if (index < 0)
 		return ret;
 
@@ -675,10 +672,6 @@ print_graph_entry_leaf(struct trace_iterator *iter,
 
 		cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 
-		/* If a graph tracer ignored set_graph_notrace */
-		if (call->depth < -1)
-			call->depth += FTRACE_NOTRACE_DEPTH;
-
 		/*
 		 * Comments display at + 1 to depth. Since
 		 * this is a leaf function, keep the comments
@@ -721,10 +714,6 @@ print_graph_entry_nested(struct trace_iterator *iter,
 		struct fgraph_cpu_data *cpu_data;
 		int cpu = iter->cpu;
 
-		/* If a graph tracer ignored set_graph_notrace */
-		if (call->depth < -1)
-			call->depth += FTRACE_NOTRACE_DEPTH;
-
 		cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 		cpu_data->depth = call->depth;
 
-- 
2.19.1

[for-next][PATCH 07/30] ftrace: Create new ftrace_internal.h header

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

In order to move function graph infrastructure into its own file (fgraph.h)
it needs to access various functions and variables in ftrace.c that are
currently static. Create a new file called ftrace-internal.h that holds the
function prototypes and the extern declarations of the variables needed by
fgraph.c as well, and make them global in ftrace.c such that they can be
used outside that file.

Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c          | 76 +++++++---------------------------
 kernel/trace/ftrace_internal.h | 75 +++++++++++++++++++++++++++++++++
 2 files changed, 89 insertions(+), 62 deletions(-)
 create mode 100644 kernel/trace/ftrace_internal.h

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 77734451cb05..52c89428b0db 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -40,6 +40,7 @@
 #include <asm/sections.h>
 #include <asm/setup.h>
 
+#include "ftrace_internal.h"
 #include "trace_output.h"
 #include "trace_stat.h"
 
@@ -77,7 +78,7 @@
 #define ASSIGN_OPS_HASH(opsname, val)
 #endif
 
-static struct ftrace_ops ftrace_list_end __read_mostly = {
+struct ftrace_ops ftrace_list_end __read_mostly = {
 	.func		= ftrace_stub,
 	.flags		= FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
 	INIT_OPS_HASH(ftrace_list_end)
@@ -112,11 +113,11 @@ static void ftrace_update_trampoline(struct ftrace_ops *ops);
  */
 static int ftrace_disabled __read_mostly;
 
-static DEFINE_MUTEX(ftrace_lock);
+DEFINE_MUTEX(ftrace_lock);
 
-static struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
+struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
-static struct ftrace_ops global_ops;
+struct ftrace_ops global_ops;
 
 #if ARCH_SUPPORTS_FTRACE_OPS
 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
@@ -127,26 +128,6 @@ static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
 #endif
 
-/*
- * Traverse the ftrace_global_list, invoking all entries.  The reason that we
- * can use rcu_dereference_raw_notrace() is that elements removed from this list
- * are simply leaked, so there is no need to interact with a grace-period
- * mechanism.  The rcu_dereference_raw_notrace() calls are needed to handle
- * concurrent insertions into the ftrace_global_list.
- *
- * Silly Alpha and silly pointer-speculation compiler optimizations!
- */
-#define do_for_each_ftrace_op(op, list)			\
-	op = rcu_dereference_raw_notrace(list);			\
-	do
-
-/*
- * Optimized for just a single item in the list (as that is the normal case).
- */
-#define while_for_each_ftrace_op(op)				\
-	while (likely(op = rcu_dereference_raw_notrace((op)->next)) &&	\
-	       unlikely((op) != &ftrace_list_end))
-
 static inline void ftrace_ops_init(struct ftrace_ops *ops)
 {
 #ifdef CONFIG_DYNAMIC_FTRACE
@@ -187,17 +168,11 @@ static void ftrace_sync_ipi(void *data)
 }
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
-static void update_function_graph_func(void);
-
 /* Both enabled by default (can be cleared by function_graph tracer flags */
 static bool fgraph_sleep_time = true;
 static bool fgraph_graph_time = true;
-
-#else
-static inline void update_function_graph_func(void) { }
 #endif
 
-
 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
 {
 	/*
@@ -334,7 +309,7 @@ static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
 
 static void ftrace_update_trampoline(struct ftrace_ops *ops);
 
-static int __register_ftrace_function(struct ftrace_ops *ops)
+int __register_ftrace_function(struct ftrace_ops *ops)
 {
 	if (ops->flags & FTRACE_OPS_FL_DELETED)
 		return -EINVAL;
@@ -375,7 +350,7 @@ static int __register_ftrace_function(struct ftrace_ops *ops)
 	return 0;
 }
 
-static int __unregister_ftrace_function(struct ftrace_ops *ops)
+int __unregister_ftrace_function(struct ftrace_ops *ops)
 {
 	int ret;
 
@@ -1022,9 +997,7 @@ static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
 #endif /* CONFIG_FUNCTION_PROFILER */
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
-static int ftrace_graph_active;
-#else
-# define ftrace_graph_active 0
+int ftrace_graph_active;
 #endif
 
 #ifdef CONFIG_DYNAMIC_FTRACE
@@ -1067,7 +1040,7 @@ static const struct ftrace_hash empty_hash = {
 };
 #define EMPTY_HASH	((struct ftrace_hash *)&empty_hash)
 
-static struct ftrace_ops global_ops = {
+struct ftrace_ops global_ops = {
 	.func				= ftrace_stub,
 	.local_hash.notrace_hash	= EMPTY_HASH,
 	.local_hash.filter_hash		= EMPTY_HASH,
@@ -1503,7 +1476,7 @@ static bool hash_contains_ip(unsigned long ip,
  * This needs to be called with preemption disabled as
  * the hashes are freed with call_rcu_sched().
  */
-static int
+int
 ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
 {
 	struct ftrace_ops_hash hash;
@@ -2682,7 +2655,7 @@ static void ftrace_startup_all(int command)
 	update_all_ops = false;
 }
 
-static int ftrace_startup(struct ftrace_ops *ops, int command)
+int ftrace_startup(struct ftrace_ops *ops, int command)
 {
 	int ret;
 
@@ -2724,7 +2697,7 @@ static int ftrace_startup(struct ftrace_ops *ops, int command)
 	return 0;
 }
 
-static int ftrace_shutdown(struct ftrace_ops *ops, int command)
+int ftrace_shutdown(struct ftrace_ops *ops, int command)
 {
 	int ret;
 
@@ -6177,7 +6150,7 @@ void ftrace_init_trace_array(struct trace_array *tr)
 }
 #else
 
-static struct ftrace_ops global_ops = {
+struct ftrace_ops global_ops = {
 	.func			= ftrace_stub,
 	.flags			= FTRACE_OPS_FL_RECURSION_SAFE |
 				  FTRACE_OPS_FL_INITIALIZED |
@@ -6194,31 +6167,10 @@ core_initcall(ftrace_nodyn_init);
 static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
 static inline void ftrace_startup_enable(int command) { }
 static inline void ftrace_startup_all(int command) { }
-/* Keep as macros so we do not need to define the commands */
-# define ftrace_startup(ops, command)					\
-	({								\
-		int ___ret = __register_ftrace_function(ops);		\
-		if (!___ret)						\
-			(ops)->flags |= FTRACE_OPS_FL_ENABLED;		\
-		___ret;							\
-	})
-# define ftrace_shutdown(ops, command)					\
-	({								\
-		int ___ret = __unregister_ftrace_function(ops);		\
-		if (!___ret)						\
-			(ops)->flags &= ~FTRACE_OPS_FL_ENABLED;		\
-		___ret;							\
-	})
 
 # define ftrace_startup_sysctl()	do { } while (0)
 # define ftrace_shutdown_sysctl()	do { } while (0)
 
-static inline int
-ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
-{
-	return 1;
-}
-
 static void ftrace_update_trampoline(struct ftrace_ops *ops)
 {
 }
@@ -6930,7 +6882,7 @@ static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
  * function against the global ops, and not just trace any function
  * that any ftrace_ops registered.
  */
-static void update_function_graph_func(void)
+void update_function_graph_func(void)
 {
 	struct ftrace_ops *op;
 	bool do_test = false;
diff --git a/kernel/trace/ftrace_internal.h b/kernel/trace/ftrace_internal.h
new file mode 100644
index 000000000000..0515a2096f90
--- /dev/null
+++ b/kernel/trace/ftrace_internal.h
@@ -0,0 +1,75 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_KERNEL_FTRACE_INTERNAL_H
+#define  _LINUX_KERNEL_FTRACE_INTERNAL_H
+
+#ifdef CONFIG_FUNCTION_TRACER
+
+/*
+ * Traverse the ftrace_global_list, invoking all entries.  The reason that we
+ * can use rcu_dereference_raw_notrace() is that elements removed from this list
+ * are simply leaked, so there is no need to interact with a grace-period
+ * mechanism.  The rcu_dereference_raw_notrace() calls are needed to handle
+ * concurrent insertions into the ftrace_global_list.
+ *
+ * Silly Alpha and silly pointer-speculation compiler optimizations!
+ */
+#define do_for_each_ftrace_op(op, list)			\
+	op = rcu_dereference_raw_notrace(list);			\
+	do
+
+/*
+ * Optimized for just a single item in the list (as that is the normal case).
+ */
+#define while_for_each_ftrace_op(op)				\
+	while (likely(op = rcu_dereference_raw_notrace((op)->next)) &&	\
+	       unlikely((op) != &ftrace_list_end))
+
+extern struct ftrace_ops __rcu *ftrace_ops_list;
+extern struct ftrace_ops ftrace_list_end;
+extern struct mutex ftrace_lock;
+extern struct ftrace_ops global_ops;
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+int ftrace_startup(struct ftrace_ops *ops, int command);
+int ftrace_shutdown(struct ftrace_ops *ops, int command);
+int ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs);
+
+#else /* !CONFIG_DYNAMIC_FTRACE */
+
+int __register_ftrace_function(struct ftrace_ops *ops);
+int __unregister_ftrace_function(struct ftrace_ops *ops);
+/* Keep as macros so we do not need to define the commands */
+# define ftrace_startup(ops, command)					\
+	({								\
+		int ___ret = __register_ftrace_function(ops);		\
+		if (!___ret)						\
+			(ops)->flags |= FTRACE_OPS_FL_ENABLED;		\
+		___ret;							\
+	})
+# define ftrace_shutdown(ops, command)					\
+	({								\
+		int ___ret = __unregister_ftrace_function(ops);		\
+		if (!___ret)						\
+			(ops)->flags &= ~FTRACE_OPS_FL_ENABLED;		\
+		___ret;							\
+	})
+static inline int
+ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
+{
+	return 1;
+}
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+extern int ftrace_graph_active;
+void update_function_graph_func(void);
+#else /* !CONFIG_FUNCTION_GRAPH_TRACER */
+# define ftrace_graph_active 0
+static inline void update_function_graph_func(void) { }
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
+#else /* !CONFIG_FUNCTION_TRACER */
+#endif /* CONFIG_FUNCTION_TRACER */
+
+#endif
-- 
2.19.1

[for-next][PATCH 08/30] function_graph: Do not expose the graph_time option when profiler is not configured

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

When the function profiler is not configured, the "graph_time" option is
meaningless, as the function profiler is the only thing that makes use of
it. Do not expose it if the profiler is not configured.

Link: http://lkml.kernel.org/r/20181123061133.GA195223@google.com

Reported-by: Joel Fernandes <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace.h                 | 5 +++++
 kernel/trace/trace_functions_graph.c | 4 ++++
 2 files changed, 9 insertions(+)

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index f67060a75f38..ab16eca76e59 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -862,7 +862,12 @@ static __always_inline bool ftrace_hash_empty(struct ftrace_hash *hash)
 #define TRACE_GRAPH_PRINT_FILL_MASK	(0x3 << TRACE_GRAPH_PRINT_FILL_SHIFT)
 
 extern void ftrace_graph_sleep_time_control(bool enable);
+
+#ifdef CONFIG_FUNCTION_PROFILER
 extern void ftrace_graph_graph_time_control(bool enable);
+#else
+static inline void ftrace_graph_graph_time_control(bool enable) { }
+#endif
 
 extern enum print_line_t
 print_graph_function_flags(struct trace_iterator *iter, u32 flags);
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index eaf9b1629956..855c13c61e77 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -60,8 +60,12 @@ static struct tracer_opt trace_opts[] = {
 	{ TRACER_OPT(funcgraph-tail, TRACE_GRAPH_PRINT_TAIL) },
 	/* Include sleep time (scheduled out) between entry and return */
 	{ TRACER_OPT(sleep-time, TRACE_GRAPH_SLEEP_TIME) },
+
+#ifdef CONFIG_FUNCTION_PROFILER
 	/* Include time within nested functions */
 	{ TRACER_OPT(graph-time, TRACE_GRAPH_GRAPH_TIME) },
+#endif
+
 	{ } /* Empty entry */
 };
 
-- 
2.19.1

[for-next][PATCH 09/30] fgraph: Move function graph specific code into fgraph.c

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

To make the function graph infrastructure more managable, the code needs to
be in its own file (fgraph.c). Move the code that is specific for managing
the function graph infrastructure out of ftrace.c and into fgraph.c

Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/fgraph.c | 360 ++++++++++++++++++++++++++++++++++++++++-
 kernel/trace/ftrace.c | 368 +-----------------------------------------
 2 files changed, 366 insertions(+), 362 deletions(-)

diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index de887a983ac7..374f3e42e29e 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -7,11 +7,27 @@
  *
  * Highly modified by Steven Rostedt (VMware).
  */
+#include <linux/suspend.h>
 #include <linux/ftrace.h>
+#include <linux/slab.h>
 
-#include "trace.h"
+#include <trace/events/sched.h>
+
+#include "ftrace_internal.h"
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+#define ASSIGN_OPS_HASH(opsname, val) \
+	.func_hash		= val, \
+	.local_hash.regex_lock	= __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
+#else
+#define ASSIGN_OPS_HASH(opsname, val)
+#endif
 
 static bool kill_ftrace_graph;
+int ftrace_graph_active;
+
+/* Both enabled by default (can be cleared by function_graph tracer flags */
+static bool fgraph_sleep_time = true;
 
 /**
  * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called
@@ -161,6 +177,31 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
 	barrier();
 }
 
+/*
+ * Hibernation protection.
+ * The state of the current task is too much unstable during
+ * suspend/restore to disk. We want to protect against that.
+ */
+static int
+ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
+							void *unused)
+{
+	switch (state) {
+	case PM_HIBERNATION_PREPARE:
+		pause_graph_tracing();
+		break;
+
+	case PM_POST_HIBERNATION:
+		unpause_graph_tracing();
+		break;
+	}
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block ftrace_suspend_notifier = {
+	.notifier_call = ftrace_suspend_notifier_call,
+};
+
 /*
  * Send the trace to the ring-buffer.
  * @return the original return address.
@@ -190,3 +231,320 @@ unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
 
 	return ret;
 }
+
+static struct ftrace_ops graph_ops = {
+	.func			= ftrace_stub,
+	.flags			= FTRACE_OPS_FL_RECURSION_SAFE |
+				   FTRACE_OPS_FL_INITIALIZED |
+				   FTRACE_OPS_FL_PID |
+				   FTRACE_OPS_FL_STUB,
+#ifdef FTRACE_GRAPH_TRAMP_ADDR
+	.trampoline		= FTRACE_GRAPH_TRAMP_ADDR,
+	/* trampoline_size is only needed for dynamically allocated tramps */
+#endif
+	ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash)
+};
+
+void ftrace_graph_sleep_time_control(bool enable)
+{
+	fgraph_sleep_time = enable;
+}
+
+int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
+{
+	return 0;
+}
+
+/* The callbacks that hook a function */
+trace_func_graph_ret_t ftrace_graph_return =
+			(trace_func_graph_ret_t)ftrace_stub;
+trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
+static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
+
+/* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
+static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
+{
+	int i;
+	int ret = 0;
+	int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
+	struct task_struct *g, *t;
+
+	for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
+		ret_stack_list[i] =
+			kmalloc_array(FTRACE_RETFUNC_DEPTH,
+				      sizeof(struct ftrace_ret_stack),
+				      GFP_KERNEL);
+		if (!ret_stack_list[i]) {
+			start = 0;
+			end = i;
+			ret = -ENOMEM;
+			goto free;
+		}
+	}
+
+	read_lock(&tasklist_lock);
+	do_each_thread(g, t) {
+		if (start == end) {
+			ret = -EAGAIN;
+			goto unlock;
+		}
+
+		if (t->ret_stack == NULL) {
+			atomic_set(&t->tracing_graph_pause, 0);
+			atomic_set(&t->trace_overrun, 0);
+			t->curr_ret_stack = -1;
+			t->curr_ret_depth = -1;
+			/* Make sure the tasks see the -1 first: */
+			smp_wmb();
+			t->ret_stack = ret_stack_list[start++];
+		}
+	} while_each_thread(g, t);
+
+unlock:
+	read_unlock(&tasklist_lock);
+free:
+	for (i = start; i < end; i++)
+		kfree(ret_stack_list[i]);
+	return ret;
+}
+
+static void
+ftrace_graph_probe_sched_switch(void *ignore, bool preempt,
+			struct task_struct *prev, struct task_struct *next)
+{
+	unsigned long long timestamp;
+	int index;
+
+	/*
+	 * Does the user want to count the time a function was asleep.
+	 * If so, do not update the time stamps.
+	 */
+	if (fgraph_sleep_time)
+		return;
+
+	timestamp = trace_clock_local();
+
+	prev->ftrace_timestamp = timestamp;
+
+	/* only process tasks that we timestamped */
+	if (!next->ftrace_timestamp)
+		return;
+
+	/*
+	 * Update all the counters in next to make up for the
+	 * time next was sleeping.
+	 */
+	timestamp -= next->ftrace_timestamp;
+
+	for (index = next->curr_ret_stack; index >= 0; index--)
+		next->ret_stack[index].calltime += timestamp;
+}
+
+static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
+{
+	if (!ftrace_ops_test(&global_ops, trace->func, NULL))
+		return 0;
+	return __ftrace_graph_entry(trace);
+}
+
+/*
+ * The function graph tracer should only trace the functions defined
+ * by set_ftrace_filter and set_ftrace_notrace. If another function
+ * tracer ops is registered, the graph tracer requires testing the
+ * function against the global ops, and not just trace any function
+ * that any ftrace_ops registered.
+ */
+void update_function_graph_func(void)
+{
+	struct ftrace_ops *op;
+	bool do_test = false;
+
+	/*
+	 * The graph and global ops share the same set of functions
+	 * to test. If any other ops is on the list, then
+	 * the graph tracing needs to test if its the function
+	 * it should call.
+	 */
+	do_for_each_ftrace_op(op, ftrace_ops_list) {
+		if (op != &global_ops && op != &graph_ops &&
+		    op != &ftrace_list_end) {
+			do_test = true;
+			/* in double loop, break out with goto */
+			goto out;
+		}
+	} while_for_each_ftrace_op(op);
+ out:
+	if (do_test)
+		ftrace_graph_entry = ftrace_graph_entry_test;
+	else
+		ftrace_graph_entry = __ftrace_graph_entry;
+}
+
+static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
+
+static void
+graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
+{
+	atomic_set(&t->tracing_graph_pause, 0);
+	atomic_set(&t->trace_overrun, 0);
+	t->ftrace_timestamp = 0;
+	/* make curr_ret_stack visible before we add the ret_stack */
+	smp_wmb();
+	t->ret_stack = ret_stack;
+}
+
+/*
+ * Allocate a return stack for the idle task. May be the first
+ * time through, or it may be done by CPU hotplug online.
+ */
+void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
+{
+	t->curr_ret_stack = -1;
+	t->curr_ret_depth = -1;
+	/*
+	 * The idle task has no parent, it either has its own
+	 * stack or no stack at all.
+	 */
+	if (t->ret_stack)
+		WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
+
+	if (ftrace_graph_active) {
+		struct ftrace_ret_stack *ret_stack;
+
+		ret_stack = per_cpu(idle_ret_stack, cpu);
+		if (!ret_stack) {
+			ret_stack =
+				kmalloc_array(FTRACE_RETFUNC_DEPTH,
+					      sizeof(struct ftrace_ret_stack),
+					      GFP_KERNEL);
+			if (!ret_stack)
+				return;
+			per_cpu(idle_ret_stack, cpu) = ret_stack;
+		}
+		graph_init_task(t, ret_stack);
+	}
+}
+
+/* Allocate a return stack for newly created task */
+void ftrace_graph_init_task(struct task_struct *t)
+{
+	/* Make sure we do not use the parent ret_stack */
+	t->ret_stack = NULL;
+	t->curr_ret_stack = -1;
+	t->curr_ret_depth = -1;
+
+	if (ftrace_graph_active) {
+		struct ftrace_ret_stack *ret_stack;
+
+		ret_stack = kmalloc_array(FTRACE_RETFUNC_DEPTH,
+					  sizeof(struct ftrace_ret_stack),
+					  GFP_KERNEL);
+		if (!ret_stack)
+			return;
+		graph_init_task(t, ret_stack);
+	}
+}
+
+void ftrace_graph_exit_task(struct task_struct *t)
+{
+	struct ftrace_ret_stack	*ret_stack = t->ret_stack;
+
+	t->ret_stack = NULL;
+	/* NULL must become visible to IRQs before we free it: */
+	barrier();
+
+	kfree(ret_stack);
+}
+
+/* Allocate a return stack for each task */
+static int start_graph_tracing(void)
+{
+	struct ftrace_ret_stack **ret_stack_list;
+	int ret, cpu;
+
+	ret_stack_list = kmalloc_array(FTRACE_RETSTACK_ALLOC_SIZE,
+				       sizeof(struct ftrace_ret_stack *),
+				       GFP_KERNEL);
+
+	if (!ret_stack_list)
+		return -ENOMEM;
+
+	/* The cpu_boot init_task->ret_stack will never be freed */
+	for_each_online_cpu(cpu) {
+		if (!idle_task(cpu)->ret_stack)
+			ftrace_graph_init_idle_task(idle_task(cpu), cpu);
+	}
+
+	do {
+		ret = alloc_retstack_tasklist(ret_stack_list);
+	} while (ret == -EAGAIN);
+
+	if (!ret) {
+		ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
+		if (ret)
+			pr_info("ftrace_graph: Couldn't activate tracepoint"
+				" probe to kernel_sched_switch\n");
+	}
+
+	kfree(ret_stack_list);
+	return ret;
+}
+
+int register_ftrace_graph(trace_func_graph_ret_t retfunc,
+			trace_func_graph_ent_t entryfunc)
+{
+	int ret = 0;
+
+	mutex_lock(&ftrace_lock);
+
+	/* we currently allow only one tracer registered at a time */
+	if (ftrace_graph_active) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	register_pm_notifier(&ftrace_suspend_notifier);
+
+	ftrace_graph_active++;
+	ret = start_graph_tracing();
+	if (ret) {
+		ftrace_graph_active--;
+		goto out;
+	}
+
+	ftrace_graph_return = retfunc;
+
+	/*
+	 * Update the indirect function to the entryfunc, and the
+	 * function that gets called to the entry_test first. Then
+	 * call the update fgraph entry function to determine if
+	 * the entryfunc should be called directly or not.
+	 */
+	__ftrace_graph_entry = entryfunc;
+	ftrace_graph_entry = ftrace_graph_entry_test;
+	update_function_graph_func();
+
+	ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET);
+out:
+	mutex_unlock(&ftrace_lock);
+	return ret;
+}
+
+void unregister_ftrace_graph(void)
+{
+	mutex_lock(&ftrace_lock);
+
+	if (unlikely(!ftrace_graph_active))
+		goto out;
+
+	ftrace_graph_active--;
+	ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
+	ftrace_graph_entry = ftrace_graph_entry_stub;
+	__ftrace_graph_entry = ftrace_graph_entry_stub;
+	ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET);
+	unregister_pm_notifier(&ftrace_suspend_notifier);
+	unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
+
+ out:
+	mutex_unlock(&ftrace_lock);
+}
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 52c89428b0db..c53533b833cf 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -19,7 +19,6 @@
 #include <linux/sched/task.h>
 #include <linux/kallsyms.h>
 #include <linux/seq_file.h>
-#include <linux/suspend.h>
 #include <linux/tracefs.h>
 #include <linux/hardirq.h>
 #include <linux/kthread.h>
@@ -167,12 +166,6 @@ static void ftrace_sync_ipi(void *data)
 	smp_rmb();
 }
 
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-/* Both enabled by default (can be cleared by function_graph tracer flags */
-static bool fgraph_sleep_time = true;
-static bool fgraph_graph_time = true;
-#endif
-
 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
 {
 	/*
@@ -790,6 +783,13 @@ function_profile_call(unsigned long ip, unsigned long parent_ip,
 }
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
+static bool fgraph_graph_time = true;
+
+void ftrace_graph_graph_time_control(bool enable)
+{
+	fgraph_graph_time = enable;
+}
+
 static int profile_graph_entry(struct ftrace_graph_ent *trace)
 {
 	int index = current->curr_ret_stack;
@@ -996,10 +996,6 @@ static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
 }
 #endif /* CONFIG_FUNCTION_PROFILER */
 
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-int ftrace_graph_active;
-#endif
-
 #ifdef CONFIG_DYNAMIC_FTRACE
 
 static struct ftrace_ops *removed_ops;
@@ -6697,353 +6693,3 @@ ftrace_enable_sysctl(struct ctl_table *table, int write,
 	mutex_unlock(&ftrace_lock);
 	return ret;
 }
-
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-
-static struct ftrace_ops graph_ops = {
-	.func			= ftrace_stub,
-	.flags			= FTRACE_OPS_FL_RECURSION_SAFE |
-				   FTRACE_OPS_FL_INITIALIZED |
-				   FTRACE_OPS_FL_PID |
-				   FTRACE_OPS_FL_STUB,
-#ifdef FTRACE_GRAPH_TRAMP_ADDR
-	.trampoline		= FTRACE_GRAPH_TRAMP_ADDR,
-	/* trampoline_size is only needed for dynamically allocated tramps */
-#endif
-	ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash)
-};
-
-void ftrace_graph_sleep_time_control(bool enable)
-{
-	fgraph_sleep_time = enable;
-}
-
-void ftrace_graph_graph_time_control(bool enable)
-{
-	fgraph_graph_time = enable;
-}
-
-int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
-{
-	return 0;
-}
-
-/* The callbacks that hook a function */
-trace_func_graph_ret_t ftrace_graph_return =
-			(trace_func_graph_ret_t)ftrace_stub;
-trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
-static trace_func_graph_ent_t __ftrace_graph_entry = ftrace_graph_entry_stub;
-
-/* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
-static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
-{
-	int i;
-	int ret = 0;
-	int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
-	struct task_struct *g, *t;
-
-	for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
-		ret_stack_list[i] =
-			kmalloc_array(FTRACE_RETFUNC_DEPTH,
-				      sizeof(struct ftrace_ret_stack),
-				      GFP_KERNEL);
-		if (!ret_stack_list[i]) {
-			start = 0;
-			end = i;
-			ret = -ENOMEM;
-			goto free;
-		}
-	}
-
-	read_lock(&tasklist_lock);
-	do_each_thread(g, t) {
-		if (start == end) {
-			ret = -EAGAIN;
-			goto unlock;
-		}
-
-		if (t->ret_stack == NULL) {
-			atomic_set(&t->tracing_graph_pause, 0);
-			atomic_set(&t->trace_overrun, 0);
-			t->curr_ret_stack = -1;
-			t->curr_ret_depth = -1;
-			/* Make sure the tasks see the -1 first: */
-			smp_wmb();
-			t->ret_stack = ret_stack_list[start++];
-		}
-	} while_each_thread(g, t);
-
-unlock:
-	read_unlock(&tasklist_lock);
-free:
-	for (i = start; i < end; i++)
-		kfree(ret_stack_list[i]);
-	return ret;
-}
-
-static void
-ftrace_graph_probe_sched_switch(void *ignore, bool preempt,
-			struct task_struct *prev, struct task_struct *next)
-{
-	unsigned long long timestamp;
-	int index;
-
-	/*
-	 * Does the user want to count the time a function was asleep.
-	 * If so, do not update the time stamps.
-	 */
-	if (fgraph_sleep_time)
-		return;
-
-	timestamp = trace_clock_local();
-
-	prev->ftrace_timestamp = timestamp;
-
-	/* only process tasks that we timestamped */
-	if (!next->ftrace_timestamp)
-		return;
-
-	/*
-	 * Update all the counters in next to make up for the
-	 * time next was sleeping.
-	 */
-	timestamp -= next->ftrace_timestamp;
-
-	for (index = next->curr_ret_stack; index >= 0; index--)
-		next->ret_stack[index].calltime += timestamp;
-}
-
-/* Allocate a return stack for each task */
-static int start_graph_tracing(void)
-{
-	struct ftrace_ret_stack **ret_stack_list;
-	int ret, cpu;
-
-	ret_stack_list = kmalloc_array(FTRACE_RETSTACK_ALLOC_SIZE,
-				       sizeof(struct ftrace_ret_stack *),
-				       GFP_KERNEL);
-
-	if (!ret_stack_list)
-		return -ENOMEM;
-
-	/* The cpu_boot init_task->ret_stack will never be freed */
-	for_each_online_cpu(cpu) {
-		if (!idle_task(cpu)->ret_stack)
-			ftrace_graph_init_idle_task(idle_task(cpu), cpu);
-	}
-
-	do {
-		ret = alloc_retstack_tasklist(ret_stack_list);
-	} while (ret == -EAGAIN);
-
-	if (!ret) {
-		ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
-		if (ret)
-			pr_info("ftrace_graph: Couldn't activate tracepoint"
-				" probe to kernel_sched_switch\n");
-	}
-
-	kfree(ret_stack_list);
-	return ret;
-}
-
-/*
- * Hibernation protection.
- * The state of the current task is too much unstable during
- * suspend/restore to disk. We want to protect against that.
- */
-static int
-ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
-							void *unused)
-{
-	switch (state) {
-	case PM_HIBERNATION_PREPARE:
-		pause_graph_tracing();
-		break;
-
-	case PM_POST_HIBERNATION:
-		unpause_graph_tracing();
-		break;
-	}
-	return NOTIFY_DONE;
-}
-
-static int ftrace_graph_entry_test(struct ftrace_graph_ent *trace)
-{
-	if (!ftrace_ops_test(&global_ops, trace->func, NULL))
-		return 0;
-	return __ftrace_graph_entry(trace);
-}
-
-/*
- * The function graph tracer should only trace the functions defined
- * by set_ftrace_filter and set_ftrace_notrace. If another function
- * tracer ops is registered, the graph tracer requires testing the
- * function against the global ops, and not just trace any function
- * that any ftrace_ops registered.
- */
-void update_function_graph_func(void)
-{
-	struct ftrace_ops *op;
-	bool do_test = false;
-
-	/*
-	 * The graph and global ops share the same set of functions
-	 * to test. If any other ops is on the list, then
-	 * the graph tracing needs to test if its the function
-	 * it should call.
-	 */
-	do_for_each_ftrace_op(op, ftrace_ops_list) {
-		if (op != &global_ops && op != &graph_ops &&
-		    op != &ftrace_list_end) {
-			do_test = true;
-			/* in double loop, break out with goto */
-			goto out;
-		}
-	} while_for_each_ftrace_op(op);
- out:
-	if (do_test)
-		ftrace_graph_entry = ftrace_graph_entry_test;
-	else
-		ftrace_graph_entry = __ftrace_graph_entry;
-}
-
-static struct notifier_block ftrace_suspend_notifier = {
-	.notifier_call = ftrace_suspend_notifier_call,
-};
-
-int register_ftrace_graph(trace_func_graph_ret_t retfunc,
-			trace_func_graph_ent_t entryfunc)
-{
-	int ret = 0;
-
-	mutex_lock(&ftrace_lock);
-
-	/* we currently allow only one tracer registered at a time */
-	if (ftrace_graph_active) {
-		ret = -EBUSY;
-		goto out;
-	}
-
-	register_pm_notifier(&ftrace_suspend_notifier);
-
-	ftrace_graph_active++;
-	ret = start_graph_tracing();
-	if (ret) {
-		ftrace_graph_active--;
-		goto out;
-	}
-
-	ftrace_graph_return = retfunc;
-
-	/*
-	 * Update the indirect function to the entryfunc, and the
-	 * function that gets called to the entry_test first. Then
-	 * call the update fgraph entry function to determine if
-	 * the entryfunc should be called directly or not.
-	 */
-	__ftrace_graph_entry = entryfunc;
-	ftrace_graph_entry = ftrace_graph_entry_test;
-	update_function_graph_func();
-
-	ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET);
-out:
-	mutex_unlock(&ftrace_lock);
-	return ret;
-}
-
-void unregister_ftrace_graph(void)
-{
-	mutex_lock(&ftrace_lock);
-
-	if (unlikely(!ftrace_graph_active))
-		goto out;
-
-	ftrace_graph_active--;
-	ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
-	ftrace_graph_entry = ftrace_graph_entry_stub;
-	__ftrace_graph_entry = ftrace_graph_entry_stub;
-	ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET);
-	unregister_pm_notifier(&ftrace_suspend_notifier);
-	unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
-
- out:
-	mutex_unlock(&ftrace_lock);
-}
-
-static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
-
-static void
-graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
-{
-	atomic_set(&t->tracing_graph_pause, 0);
-	atomic_set(&t->trace_overrun, 0);
-	t->ftrace_timestamp = 0;
-	/* make curr_ret_stack visible before we add the ret_stack */
-	smp_wmb();
-	t->ret_stack = ret_stack;
-}
-
-/*
- * Allocate a return stack for the idle task. May be the first
- * time through, or it may be done by CPU hotplug online.
- */
-void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
-{
-	t->curr_ret_stack = -1;
-	t->curr_ret_depth = -1;
-	/*
-	 * The idle task has no parent, it either has its own
-	 * stack or no stack at all.
-	 */
-	if (t->ret_stack)
-		WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
-
-	if (ftrace_graph_active) {
-		struct ftrace_ret_stack *ret_stack;
-
-		ret_stack = per_cpu(idle_ret_stack, cpu);
-		if (!ret_stack) {
-			ret_stack =
-				kmalloc_array(FTRACE_RETFUNC_DEPTH,
-					      sizeof(struct ftrace_ret_stack),
-					      GFP_KERNEL);
-			if (!ret_stack)
-				return;
-			per_cpu(idle_ret_stack, cpu) = ret_stack;
-		}
-		graph_init_task(t, ret_stack);
-	}
-}
-
-/* Allocate a return stack for newly created task */
-void ftrace_graph_init_task(struct task_struct *t)
-{
-	/* Make sure we do not use the parent ret_stack */
-	t->ret_stack = NULL;
-	t->curr_ret_stack = -1;
-	t->curr_ret_depth = -1;
-
-	if (ftrace_graph_active) {
-		struct ftrace_ret_stack *ret_stack;
-
-		ret_stack = kmalloc_array(FTRACE_RETFUNC_DEPTH,
-					  sizeof(struct ftrace_ret_stack),
-					  GFP_KERNEL);
-		if (!ret_stack)
-			return;
-		graph_init_task(t, ret_stack);
-	}
-}
-
-void ftrace_graph_exit_task(struct task_struct *t)
-{
-	struct ftrace_ret_stack	*ret_stack = t->ret_stack;
-
-	t->ret_stack = NULL;
-	/* NULL must become visible to IRQs before we free it: */
-	barrier();
-
-	kfree(ret_stack);
-}
-#endif
-- 
2.19.1

[for-next][PATCH 10/30] tracing: Rearrange functions in trace_sched_wakeup.c

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Rearrange the functions in trace_sched_wakeup.c so that there are fewer
 #ifdef CONFIG_FUNCTION_TRACER and #ifdef CONFIG_FUNCTION_GRAPH_TRACER,
instead of having the #ifdefs spread all over.

No functional change is made.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_sched_wakeup.c | 272 ++++++++++++++----------------
 1 file changed, 130 insertions(+), 142 deletions(-)

diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 7d04b9890755..2ce78100b4d3 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -35,26 +35,19 @@ static arch_spinlock_t wakeup_lock =
 
 static void wakeup_reset(struct trace_array *tr);
 static void __wakeup_reset(struct trace_array *tr);
+static int start_func_tracer(struct trace_array *tr, int graph);
+static void stop_func_tracer(struct trace_array *tr, int graph);
 
 static int save_flags;
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
-static int wakeup_display_graph(struct trace_array *tr, int set);
 # define is_graph(tr) ((tr)->trace_flags & TRACE_ITER_DISPLAY_GRAPH)
 #else
-static inline int wakeup_display_graph(struct trace_array *tr, int set)
-{
-	return 0;
-}
 # define is_graph(tr) false
 #endif
 
-
 #ifdef CONFIG_FUNCTION_TRACER
 
-static int wakeup_graph_entry(struct ftrace_graph_ent *trace);
-static void wakeup_graph_return(struct ftrace_graph_ret *trace);
-
 static bool function_enabled;
 
 /*
@@ -104,122 +97,8 @@ func_prolog_preempt_disable(struct trace_array *tr,
 	return 0;
 }
 
-/*
- * wakeup uses its own tracer function to keep the overhead down:
- */
-static void
-wakeup_tracer_call(unsigned long ip, unsigned long parent_ip,
-		   struct ftrace_ops *op, struct pt_regs *pt_regs)
-{
-	struct trace_array *tr = wakeup_trace;
-	struct trace_array_cpu *data;
-	unsigned long flags;
-	int pc;
-
-	if (!func_prolog_preempt_disable(tr, &data, &pc))
-		return;
-
-	local_irq_save(flags);
-	trace_function(tr, ip, parent_ip, flags, pc);
-	local_irq_restore(flags);
-
-	atomic_dec(&data->disabled);
-	preempt_enable_notrace();
-}
-
-static int register_wakeup_function(struct trace_array *tr, int graph, int set)
-{
-	int ret;
-
-	/* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
-	if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION)))
-		return 0;
-
-	if (graph)
-		ret = register_ftrace_graph(&wakeup_graph_return,
-					    &wakeup_graph_entry);
-	else
-		ret = register_ftrace_function(tr->ops);
-
-	if (!ret)
-		function_enabled = true;
-
-	return ret;
-}
-
-static void unregister_wakeup_function(struct trace_array *tr, int graph)
-{
-	if (!function_enabled)
-		return;
-
-	if (graph)
-		unregister_ftrace_graph();
-	else
-		unregister_ftrace_function(tr->ops);
-
-	function_enabled = false;
-}
-
-static int wakeup_function_set(struct trace_array *tr, u32 mask, int set)
-{
-	if (!(mask & TRACE_ITER_FUNCTION))
-		return 0;
-
-	if (set)
-		register_wakeup_function(tr, is_graph(tr), 1);
-	else
-		unregister_wakeup_function(tr, is_graph(tr));
-	return 1;
-}
-#else
-static int register_wakeup_function(struct trace_array *tr, int graph, int set)
-{
-	return 0;
-}
-static void unregister_wakeup_function(struct trace_array *tr, int graph) { }
-static int wakeup_function_set(struct trace_array *tr, u32 mask, int set)
-{
-	return 0;
-}
-#endif /* CONFIG_FUNCTION_TRACER */
-
-static int wakeup_flag_changed(struct trace_array *tr, u32 mask, int set)
-{
-	struct tracer *tracer = tr->current_trace;
-
-	if (wakeup_function_set(tr, mask, set))
-		return 0;
-
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	if (mask & TRACE_ITER_DISPLAY_GRAPH)
-		return wakeup_display_graph(tr, set);
-#endif
-
-	return trace_keep_overwrite(tracer, mask, set);
-}
 
-static int start_func_tracer(struct trace_array *tr, int graph)
-{
-	int ret;
-
-	ret = register_wakeup_function(tr, graph, 0);
-
-	if (!ret && tracing_is_enabled())
-		tracer_enabled = 1;
-	else
-		tracer_enabled = 0;
-
-	return ret;
-}
-
-static void stop_func_tracer(struct trace_array *tr, int graph)
-{
-	tracer_enabled = 0;
-
-	unregister_wakeup_function(tr, graph);
-}
-
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 static int wakeup_display_graph(struct trace_array *tr, int set)
 {
 	if (!(is_graph(tr) ^ set))
@@ -318,20 +197,94 @@ static void wakeup_print_header(struct seq_file *s)
 	else
 		trace_default_header(s);
 }
+#else /* CONFIG_FUNCTION_GRAPH_TRACER */
+static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
+{
+	return -1;
+}
+static void wakeup_graph_return(struct ftrace_graph_ret *trace) { }
+#endif /* else CONFIG_FUNCTION_GRAPH_TRACER */
 
+/*
+ * wakeup uses its own tracer function to keep the overhead down:
+ */
 static void
-__trace_function(struct trace_array *tr,
-		 unsigned long ip, unsigned long parent_ip,
-		 unsigned long flags, int pc)
+wakeup_tracer_call(unsigned long ip, unsigned long parent_ip,
+		   struct ftrace_ops *op, struct pt_regs *pt_regs)
 {
-	if (is_graph(tr))
-		trace_graph_function(tr, ip, parent_ip, flags, pc);
+	struct trace_array *tr = wakeup_trace;
+	struct trace_array_cpu *data;
+	unsigned long flags;
+	int pc;
+
+	if (!func_prolog_preempt_disable(tr, &data, &pc))
+		return;
+
+	local_irq_save(flags);
+	trace_function(tr, ip, parent_ip, flags, pc);
+	local_irq_restore(flags);
+
+	atomic_dec(&data->disabled);
+	preempt_enable_notrace();
+}
+
+static int register_wakeup_function(struct trace_array *tr, int graph, int set)
+{
+	int ret;
+
+	/* 'set' is set if TRACE_ITER_FUNCTION is about to be set */
+	if (function_enabled || (!set && !(tr->trace_flags & TRACE_ITER_FUNCTION)))
+		return 0;
+
+	if (graph)
+		ret = register_ftrace_graph(&wakeup_graph_return,
+					    &wakeup_graph_entry);
 	else
-		trace_function(tr, ip, parent_ip, flags, pc);
+		ret = register_ftrace_function(tr->ops);
+
+	if (!ret)
+		function_enabled = true;
+
+	return ret;
 }
-#else
-#define __trace_function trace_function
 
+static void unregister_wakeup_function(struct trace_array *tr, int graph)
+{
+	if (!function_enabled)
+		return;
+
+	if (graph)
+		unregister_ftrace_graph();
+	else
+		unregister_ftrace_function(tr->ops);
+
+	function_enabled = false;
+}
+
+static int wakeup_function_set(struct trace_array *tr, u32 mask, int set)
+{
+	if (!(mask & TRACE_ITER_FUNCTION))
+		return 0;
+
+	if (set)
+		register_wakeup_function(tr, is_graph(tr), 1);
+	else
+		unregister_wakeup_function(tr, is_graph(tr));
+	return 1;
+}
+#else /* CONFIG_FUNCTION_TRACER */
+static int register_wakeup_function(struct trace_array *tr, int graph, int set)
+{
+	return 0;
+}
+static void unregister_wakeup_function(struct trace_array *tr, int graph) { }
+static int wakeup_function_set(struct trace_array *tr, u32 mask, int set)
+{
+	return 0;
+}
+#endif /* else CONFIG_FUNCTION_TRACER */
+
+#ifndef CONFIG_FUNCTION_GRAPH_TRACER
 static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
 {
 	return TRACE_TYPE_UNHANDLED;
@@ -340,23 +293,58 @@ static enum print_line_t wakeup_print_line(struct trace_iterator *iter)
 static void wakeup_trace_open(struct trace_iterator *iter) { }
 static void wakeup_trace_close(struct trace_iterator *iter) { }
 
-#ifdef CONFIG_FUNCTION_TRACER
-static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
-{
-	return -1;
-}
-static void wakeup_graph_return(struct ftrace_graph_ret *trace) { }
 static void wakeup_print_header(struct seq_file *s)
 {
 	trace_default_header(s);
 }
-#else
-static void wakeup_print_header(struct seq_file *s)
+#endif /* !CONFIG_FUNCTION_GRAPH_TRACER */
+
+static void
+__trace_function(struct trace_array *tr,
+		 unsigned long ip, unsigned long parent_ip,
+		 unsigned long flags, int pc)
+{
+	if (is_graph(tr))
+		trace_graph_function(tr, ip, parent_ip, flags, pc);
+	else
+		trace_function(tr, ip, parent_ip, flags, pc);
+}
+
+static int wakeup_flag_changed(struct trace_array *tr, u32 mask, int set)
 {
-	trace_latency_header(s);
+	struct tracer *tracer = tr->current_trace;
+
+	if (wakeup_function_set(tr, mask, set))
+		return 0;
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	if (mask & TRACE_ITER_DISPLAY_GRAPH)
+		return wakeup_display_graph(tr, set);
+#endif
+
+	return trace_keep_overwrite(tracer, mask, set);
+}
+
+static int start_func_tracer(struct trace_array *tr, int graph)
+{
+	int ret;
+
+	ret = register_wakeup_function(tr, graph, 0);
+
+	if (!ret && tracing_is_enabled())
+		tracer_enabled = 1;
+	else
+		tracer_enabled = 0;
+
+	return ret;
+}
+
+static void stop_func_tracer(struct trace_array *tr, int graph)
+{
+	tracer_enabled = 0;
+
+	unregister_wakeup_function(tr, graph);
 }
-#endif /* CONFIG_FUNCTION_TRACER */
-#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
 /*
  * Should this new latency be reported/recorded?
-- 
2.19.1

[for-next][PATCH 11/30] fgraph: Add new fgraph_ops structure to enable function graph hooks

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Currently the registering of function graph is to pass in a entry and return
function. We need to have a way to associate those functions together where
the entry can determine to run the return hook. Having a structure that
contains both functions will facilitate the process of converting the code
to be able to do such.

This is similar to the way function hooks are enabled (it passes in
ftrace_ops). Instead of passing in the functions to use, a single structure
is passed in to the registering function.

The unregister function is now passed in the fgraph_ops handle. When we
allow more than one callback to the function graph hooks, this will let the
system know which one to remove.

Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/linux/ftrace.h               | 21 +++++++++++----------
 kernel/trace/fgraph.c                |  9 ++++-----
 kernel/trace/ftrace.c                | 10 +++++++---
 kernel/trace/trace_functions_graph.c | 21 ++++++++++++++++-----
 kernel/trace/trace_irqsoff.c         | 18 +++++++-----------
 kernel/trace/trace_sched_wakeup.c    | 16 +++++++---------
 kernel/trace/trace_selftest.c        |  8 ++++++--
 7 files changed, 58 insertions(+), 45 deletions(-)

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 98625f10d982..21c80491ccde 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -749,6 +749,11 @@ typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 
+struct fgraph_ops {
+	trace_func_graph_ent_t		entryfunc;
+	trace_func_graph_ret_t		retfunc;
+};
+
 /*
  * Stack of return addresses for functions
  * of a thread.
@@ -792,8 +797,9 @@ unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
 
 #define FTRACE_RETFUNC_DEPTH 50
 #define FTRACE_RETSTACK_ALLOC_SIZE 32
-extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
-				trace_func_graph_ent_t entryfunc);
+
+extern int register_ftrace_graph(struct fgraph_ops *ops);
+extern void unregister_ftrace_graph(struct fgraph_ops *ops);
 
 extern bool ftrace_graph_is_dead(void);
 extern void ftrace_graph_stop(void);
@@ -802,8 +808,6 @@ extern void ftrace_graph_stop(void);
 extern trace_func_graph_ret_t ftrace_graph_return;
 extern trace_func_graph_ent_t ftrace_graph_entry;
 
-extern void unregister_ftrace_graph(void);
-
 extern void ftrace_graph_init_task(struct task_struct *t);
 extern void ftrace_graph_exit_task(struct task_struct *t);
 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
@@ -825,12 +829,9 @@ static inline void ftrace_graph_init_task(struct task_struct *t) { }
 static inline void ftrace_graph_exit_task(struct task_struct *t) { }
 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
 
-static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc,
-			  trace_func_graph_ent_t entryfunc)
-{
-	return -1;
-}
-static inline void unregister_ftrace_graph(void) { }
+/* Define as macros as fgraph_ops may not be defined */
+#define register_ftrace_graph(ops) ({ -1; })
+#define unregister_ftrace_graph(ops) do { } while (0)
 
 static inline unsigned long
 ftrace_graph_ret_addr(struct task_struct *task, int *idx, unsigned long ret,
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index 374f3e42e29e..cc35606e9a3e 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -490,8 +490,7 @@ static int start_graph_tracing(void)
 	return ret;
 }
 
-int register_ftrace_graph(trace_func_graph_ret_t retfunc,
-			trace_func_graph_ent_t entryfunc)
+int register_ftrace_graph(struct fgraph_ops *gops)
 {
 	int ret = 0;
 
@@ -512,7 +511,7 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 		goto out;
 	}
 
-	ftrace_graph_return = retfunc;
+	ftrace_graph_return = gops->retfunc;
 
 	/*
 	 * Update the indirect function to the entryfunc, and the
@@ -520,7 +519,7 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 	 * call the update fgraph entry function to determine if
 	 * the entryfunc should be called directly or not.
 	 */
-	__ftrace_graph_entry = entryfunc;
+	__ftrace_graph_entry = gops->entryfunc;
 	ftrace_graph_entry = ftrace_graph_entry_test;
 	update_function_graph_func();
 
@@ -530,7 +529,7 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 	return ret;
 }
 
-void unregister_ftrace_graph(void)
+void unregister_ftrace_graph(struct fgraph_ops *gops)
 {
 	mutex_lock(&ftrace_lock);
 
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index c53533b833cf..d06fe588e650 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -849,15 +849,19 @@ static void profile_graph_return(struct ftrace_graph_ret *trace)
 	local_irq_restore(flags);
 }
 
+static struct fgraph_ops fprofiler_ops = {
+	.entryfunc = &profile_graph_entry,
+	.retfunc = &profile_graph_return,
+};
+
 static int register_ftrace_profiler(void)
 {
-	return register_ftrace_graph(&profile_graph_return,
-				     &profile_graph_entry);
+	return register_ftrace_graph(&fprofiler_ops);
 }
 
 static void unregister_ftrace_profiler(void)
 {
-	unregister_ftrace_graph();
+	unregister_ftrace_graph(&fprofiler_ops);
 }
 #else
 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 855c13c61e77..140b4b51ab34 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -345,17 +345,25 @@ static void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
 		trace_graph_return(trace);
 }
 
+static struct fgraph_ops funcgraph_thresh_ops = {
+	.entryfunc = &trace_graph_entry,
+	.retfunc = &trace_graph_thresh_return,
+};
+
+static struct fgraph_ops funcgraph_ops = {
+	.entryfunc = &trace_graph_entry,
+	.retfunc = &trace_graph_return,
+};
+
 static int graph_trace_init(struct trace_array *tr)
 {
 	int ret;
 
 	set_graph_array(tr);
 	if (tracing_thresh)
-		ret = register_ftrace_graph(&trace_graph_thresh_return,
-					    &trace_graph_entry);
+		ret = register_ftrace_graph(&funcgraph_thresh_ops);
 	else
-		ret = register_ftrace_graph(&trace_graph_return,
-					    &trace_graph_entry);
+		ret = register_ftrace_graph(&funcgraph_ops);
 	if (ret)
 		return ret;
 	tracing_start_cmdline_record();
@@ -366,7 +374,10 @@ static int graph_trace_init(struct trace_array *tr)
 static void graph_trace_reset(struct trace_array *tr)
 {
 	tracing_stop_cmdline_record();
-	unregister_ftrace_graph();
+	if (tracing_thresh)
+		unregister_ftrace_graph(&funcgraph_thresh_ops);
+	else
+		unregister_ftrace_graph(&funcgraph_ops);
 }
 
 static int graph_trace_update_thresh(struct trace_array *tr)
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 98ea6d28df15..d3294721f119 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -218,6 +218,11 @@ static void irqsoff_graph_return(struct ftrace_graph_ret *trace)
 	atomic_dec(&data->disabled);
 }
 
+static struct fgraph_ops fgraph_ops = {
+	.entryfunc		= &irqsoff_graph_entry,
+	.retfunc		= &irqsoff_graph_return,
+};
+
 static void irqsoff_trace_open(struct trace_iterator *iter)
 {
 	if (is_graph(iter->tr))
@@ -272,13 +277,6 @@ __trace_function(struct trace_array *tr,
 #else
 #define __trace_function trace_function
 
-#ifdef CONFIG_FUNCTION_TRACER
-static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
-{
-	return -1;
-}
-#endif
-
 static enum print_line_t irqsoff_print_line(struct trace_iterator *iter)
 {
 	return TRACE_TYPE_UNHANDLED;
@@ -288,7 +286,6 @@ static void irqsoff_trace_open(struct trace_iterator *iter) { }
 static void irqsoff_trace_close(struct trace_iterator *iter) { }
 
 #ifdef CONFIG_FUNCTION_TRACER
-static void irqsoff_graph_return(struct ftrace_graph_ret *trace) { }
 static void irqsoff_print_header(struct seq_file *s)
 {
 	trace_default_header(s);
@@ -468,8 +465,7 @@ static int register_irqsoff_function(struct trace_array *tr, int graph, int set)
 		return 0;
 
 	if (graph)
-		ret = register_ftrace_graph(&irqsoff_graph_return,
-					    &irqsoff_graph_entry);
+		ret = register_ftrace_graph(&fgraph_ops);
 	else
 		ret = register_ftrace_function(tr->ops);
 
@@ -485,7 +481,7 @@ static void unregister_irqsoff_function(struct trace_array *tr, int graph)
 		return;
 
 	if (graph)
-		unregister_ftrace_graph();
+		unregister_ftrace_graph(&fgraph_ops);
 	else
 		unregister_ftrace_function(tr->ops);
 
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 2ce78100b4d3..4ea7e6845efb 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -162,6 +162,11 @@ static void wakeup_graph_return(struct ftrace_graph_ret *trace)
 	return;
 }
 
+static struct fgraph_ops fgraph_wakeup_ops = {
+	.entryfunc = &wakeup_graph_entry,
+	.retfunc = &wakeup_graph_return,
+};
+
 static void wakeup_trace_open(struct trace_iterator *iter)
 {
 	if (is_graph(iter->tr))
@@ -197,12 +202,6 @@ static void wakeup_print_header(struct seq_file *s)
 	else
 		trace_default_header(s);
 }
-#else /* CONFIG_FUNCTION_GRAPH_TRACER */
-static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
-{
-	return -1;
-}
-static void wakeup_graph_return(struct ftrace_graph_ret *trace) { }
 #endif /* else CONFIG_FUNCTION_GRAPH_TRACER */
 
 /*
@@ -237,8 +236,7 @@ static int register_wakeup_function(struct trace_array *tr, int graph, int set)
 		return 0;
 
 	if (graph)
-		ret = register_ftrace_graph(&wakeup_graph_return,
-					    &wakeup_graph_entry);
+		ret = register_ftrace_graph(&fgraph_wakeup_ops);
 	else
 		ret = register_ftrace_function(tr->ops);
 
@@ -254,7 +252,7 @@ static void unregister_wakeup_function(struct trace_array *tr, int graph)
 		return;
 
 	if (graph)
-		unregister_ftrace_graph();
+		unregister_ftrace_graph(&fgraph_wakeup_ops);
 	else
 		unregister_ftrace_function(tr->ops);
 
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 11e9daa4a568..9d402e7fc949 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -741,6 +741,11 @@ static int trace_graph_entry_watchdog(struct ftrace_graph_ent *trace)
 	return trace_graph_entry(trace);
 }
 
+static struct fgraph_ops fgraph_ops __initdata  = {
+	.entryfunc		= &trace_graph_entry_watchdog,
+	.retfunc		= &trace_graph_return,
+};
+
 /*
  * Pretty much the same than for the function tracer from which the selftest
  * has been borrowed.
@@ -765,8 +770,7 @@ trace_selftest_startup_function_graph(struct tracer *trace,
 	 */
 	tracing_reset_online_cpus(&tr->trace_buffer);
 	set_graph_array(tr);
-	ret = register_ftrace_graph(&trace_graph_return,
-				    &trace_graph_entry_watchdog);
+	ret = register_ftrace_graph(&fgraph_ops);
 	if (ret) {
 		warn_failed_init_tracer(trace, ret);
 		goto out;
-- 
2.19.1

[for-next][PATCH 12/30] function_graph: Move ftrace_graph_ret_addr() to fgraph.c

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Move the function function_graph_ret_addr() to fgraph.c, as the management
of the curr_ret_stack is going to change, and all the accesses to ret_stack
needs to be done in fgraph.c.

Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/fgraph.c                | 55 ++++++++++++++++++++++++++++
 kernel/trace/trace_functions_graph.c | 55 ----------------------------
 2 files changed, 55 insertions(+), 55 deletions(-)

diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index cc35606e9a3e..90fcefcaff2a 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -232,6 +232,61 @@ unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
 	return ret;
 }
 
+/**
+ * ftrace_graph_ret_addr - convert a potentially modified stack return address
+ *			   to its original value
+ *
+ * This function can be called by stack unwinding code to convert a found stack
+ * return address ('ret') to its original value, in case the function graph
+ * tracer has modified it to be 'return_to_handler'.  If the address hasn't
+ * been modified, the unchanged value of 'ret' is returned.
+ *
+ * 'idx' is a state variable which should be initialized by the caller to zero
+ * before the first call.
+ *
+ * 'retp' is a pointer to the return address on the stack.  It's ignored if
+ * the arch doesn't have HAVE_FUNCTION_GRAPH_RET_ADDR_PTR defined.
+ */
+#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
+unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
+				    unsigned long ret, unsigned long *retp)
+{
+	int index = task->curr_ret_stack;
+	int i;
+
+	if (ret != (unsigned long)return_to_handler)
+		return ret;
+
+	if (index < 0)
+		return ret;
+
+	for (i = 0; i <= index; i++)
+		if (task->ret_stack[i].retp == retp)
+			return task->ret_stack[i].ret;
+
+	return ret;
+}
+#else /* !HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */
+unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
+				    unsigned long ret, unsigned long *retp)
+{
+	int task_idx;
+
+	if (ret != (unsigned long)return_to_handler)
+		return ret;
+
+	task_idx = task->curr_ret_stack;
+
+	if (!task->ret_stack || task_idx < *idx)
+		return ret;
+
+	task_idx -= *idx;
+	(*idx)++;
+
+	return task->ret_stack[task_idx].ret;
+}
+#endif /* HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */
+
 static struct ftrace_ops graph_ops = {
 	.func			= ftrace_stub,
 	.flags			= FTRACE_OPS_FL_RECURSION_SAFE |
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 140b4b51ab34..c2af1560e856 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -94,61 +94,6 @@ static void
 print_graph_duration(struct trace_array *tr, unsigned long long duration,
 		     struct trace_seq *s, u32 flags);
 
-/**
- * ftrace_graph_ret_addr - convert a potentially modified stack return address
- *			   to its original value
- *
- * This function can be called by stack unwinding code to convert a found stack
- * return address ('ret') to its original value, in case the function graph
- * tracer has modified it to be 'return_to_handler'.  If the address hasn't
- * been modified, the unchanged value of 'ret' is returned.
- *
- * 'idx' is a state variable which should be initialized by the caller to zero
- * before the first call.
- *
- * 'retp' is a pointer to the return address on the stack.  It's ignored if
- * the arch doesn't have HAVE_FUNCTION_GRAPH_RET_ADDR_PTR defined.
- */
-#ifdef HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
-unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
-				    unsigned long ret, unsigned long *retp)
-{
-	int index = task->curr_ret_stack;
-	int i;
-
-	if (ret != (unsigned long)return_to_handler)
-		return ret;
-
-	if (index < 0)
-		return ret;
-
-	for (i = 0; i <= index; i++)
-		if (task->ret_stack[i].retp == retp)
-			return task->ret_stack[i].ret;
-
-	return ret;
-}
-#else /* !HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */
-unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
-				    unsigned long ret, unsigned long *retp)
-{
-	int task_idx;
-
-	if (ret != (unsigned long)return_to_handler)
-		return ret;
-
-	task_idx = task->curr_ret_stack;
-
-	if (!task->ret_stack || task_idx < *idx)
-		return ret;
-
-	task_idx -= *idx;
-	(*idx)++;
-
-	return task->ret_stack[task_idx].ret;
-}
-#endif /* HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */
-
 int __trace_graph_entry(struct trace_array *tr,
 				struct ftrace_graph_ent *trace,
 				unsigned long flags,
-- 
2.19.1

[for-next][PATCH 13/30] function_graph: Have profiler use new helper ftrace_graph_get_ret_stack()

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

The ret_stack processing is going to change, and that is going
to break anything that is accessing the ret_stack directly. One user is the
function graph profiler. By using the ftrace_graph_get_ret_stack() helper
function, the profiler can access the ret_stack entry without relying on the
implementation details of the stack itself.

Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/linux/ftrace.h |  3 +++
 kernel/trace/fgraph.c  | 11 +++++++++++
 kernel/trace/ftrace.c  | 21 +++++++++++----------
 3 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 21c80491ccde..98e141c71ad0 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -785,6 +785,9 @@ extern int
 function_graph_enter(unsigned long ret, unsigned long func,
 		     unsigned long frame_pointer, unsigned long *retp);
 
+struct ftrace_ret_stack *
+ftrace_graph_get_ret_stack(struct task_struct *task, int idx);
+
 unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
 				    unsigned long ret, unsigned long *retp);
 
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index 90fcefcaff2a..a3704ec8b599 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -232,6 +232,17 @@ unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
 	return ret;
 }
 
+struct ftrace_ret_stack *
+ftrace_graph_get_ret_stack(struct task_struct *task, int idx)
+{
+	idx = current->curr_ret_stack - idx;
+
+	if (idx >= 0 && idx <= task->curr_ret_stack)
+		return &current->ret_stack[idx];
+
+	return NULL;
+}
+
 /**
  * ftrace_graph_ret_addr - convert a potentially modified stack return address
  *			   to its original value
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index d06fe588e650..8ef9fc226037 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -792,7 +792,7 @@ void ftrace_graph_graph_time_control(bool enable)
 
 static int profile_graph_entry(struct ftrace_graph_ent *trace)
 {
-	int index = current->curr_ret_stack;
+	struct ftrace_ret_stack *ret_stack;
 
 	function_profile_call(trace->func, 0, NULL, NULL);
 
@@ -800,14 +800,16 @@ static int profile_graph_entry(struct ftrace_graph_ent *trace)
 	if (!current->ret_stack)
 		return 0;
 
-	if (index >= 0 && index < FTRACE_RETFUNC_DEPTH)
-		current->ret_stack[index].subtime = 0;
+	ret_stack = ftrace_graph_get_ret_stack(current, 0);
+	if (ret_stack)
+		ret_stack->subtime = 0;
 
 	return 1;
 }
 
 static void profile_graph_return(struct ftrace_graph_ret *trace)
 {
+	struct ftrace_ret_stack *ret_stack;
 	struct ftrace_profile_stat *stat;
 	unsigned long long calltime;
 	struct ftrace_profile *rec;
@@ -825,16 +827,15 @@ static void profile_graph_return(struct ftrace_graph_ret *trace)
 	calltime = trace->rettime - trace->calltime;
 
 	if (!fgraph_graph_time) {
-		int index;
-
-		index = current->curr_ret_stack;
 
 		/* Append this call time to the parent time to subtract */
-		if (index)
-			current->ret_stack[index - 1].subtime += calltime;
+		ret_stack = ftrace_graph_get_ret_stack(current, 1);
+		if (ret_stack)
+			ret_stack->subtime += calltime;
 
-		if (current->ret_stack[index].subtime < calltime)
-			calltime -= current->ret_stack[index].subtime;
+		ret_stack = ftrace_graph_get_ret_stack(current, 0);
+		if (ret_stack && ret_stack->subtime < calltime)
+			calltime -= ret_stack->subtime;
 		else
 			calltime = 0;
 	}
-- 
2.19.1

[for-next][PATCH 14/30] tracing: Have trace_stack nr_entries compare not be so subtle

[Steven Rostedt]

From: Dan Carpenter <dan.carpenter@oracle.com>

Dan Carpenter reviewed the trace_stack.c code and figured he found an off by
one bug.

 "From reviewing the code, it seems possible for
  stack_trace_max.nr_entries to be set to .max_entries and in that case we
  would be reading one element beyond the end of the stack_dump_trace[]
  array.  If it's not set to .max_entries then the bug doesn't affect
  runtime."

Although it looks to be the case, it is not. Because we have:

 static unsigned long stack_dump_trace[STACK_TRACE_ENTRIES+1] =
	 { [0 ... (STACK_TRACE_ENTRIES)] = ULONG_MAX };

 struct stack_trace stack_trace_max = {
	.max_entries		= STACK_TRACE_ENTRIES - 1,
	.entries		= &stack_dump_trace[0],
 };

And:

	stack_trace_max.nr_entries = x;
	for (; x < i; x++)
		stack_dump_trace[x] = ULONG_MAX;

Even if nr_entries equals max_entries, indexing with it into the
stack_dump_trace[] array will not overflow the array. But if it is the case,
the second part of the conditional that tests stack_dump_trace[nr_entries]
to ULONG_MAX will always be true.

By applying Dan's patch, it removes the subtle aspect of it and makes the if
conditional slightly more efficient.

Link: http://lkml.kernel.org/r/20180620110758.crunhd5bfep7zuiz@kili.mountain

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_stack.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 2b0d1ee3241c..e2a153fc1afc 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -286,7 +286,7 @@ __next(struct seq_file *m, loff_t *pos)
 {
 	long n = *pos - 1;
 
-	if (n > stack_trace_max.nr_entries || stack_dump_trace[n] == ULONG_MAX)
+	if (n >= stack_trace_max.nr_entries || stack_dump_trace[n] == ULONG_MAX)
 		return NULL;
 
 	m->private = (void *)n;
-- 
2.19.1

[for-next][PATCH 15/30] scripts/recordmcount.{c,pl}: support -ffunction-sections .text.* section names

[Steven Rostedt]

From: Joe Lawrence <joe.lawrence@redhat.com>

When building with -ffunction-sections, the compiler will place each
function into its own ELF section, prefixed with ".text".  For example,
a simple test module with functions test_module_do_work() and
test_module_wq_func():

  % objdump --section-headers test_module.o | awk '/\.text/{print $2}'
  .text
  .text.test_module_do_work
  .text.test_module_wq_func
  .init.text
  .exit.text

Adjust the recordmcount scripts to look for ".text" as a section name
prefix.  This will ensure that those functions will be included in the
__mcount_loc relocations:

  % objdump --reloc --section __mcount_loc test_module.o
  OFFSET           TYPE              VALUE
  0000000000000000 R_X86_64_64       .text.test_module_do_work
  0000000000000008 R_X86_64_64       .text.test_module_wq_func
  0000000000000010 R_X86_64_64       .init.text

Link: http://lkml.kernel.org/r/1542745158-25392-2-git-send-email-joe.lawrence@redhat.com

Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 scripts/recordmcount.c  |  2 +-
 scripts/recordmcount.pl | 13 +++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c
index 895c40e8679f..a50a2aa963ad 100644
--- a/scripts/recordmcount.c
+++ b/scripts/recordmcount.c
@@ -397,7 +397,7 @@ static uint32_t (*w2)(uint16_t);
 static int
 is_mcounted_section_name(char const *const txtname)
 {
-	return strcmp(".text",           txtname) == 0 ||
+	return strncmp(".text",          txtname, 5) == 0 ||
 		strcmp(".init.text",     txtname) == 0 ||
 		strcmp(".ref.text",      txtname) == 0 ||
 		strcmp(".sched.text",    txtname) == 0 ||
diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl
index f599031260d5..68841d01162c 100755
--- a/scripts/recordmcount.pl
+++ b/scripts/recordmcount.pl
@@ -142,6 +142,11 @@ my %text_sections = (
      ".text.unlikely" => 1,
 );
 
+# Acceptable section-prefixes to record.
+my %text_section_prefixes = (
+     ".text." => 1,
+);
+
 # Note: we are nice to C-programmers here, thus we skip the '||='-idiom.
 $objdump = 'objdump' if (!$objdump);
 $objcopy = 'objcopy' if (!$objcopy);
@@ -519,6 +524,14 @@ while (<IN>) {
 
 	# Only record text sections that we know are safe
 	$read_function = defined($text_sections{$1});
+	if (!$read_function) {
+	    foreach my $prefix (keys %text_section_prefixes) {
+	        if (substr($1, 0, length $prefix) eq $prefix) {
+	            $read_function = 1;
+	            last;
+	        }
+	    }
+	}
 	# print out any recorded offsets
 	update_funcs();
 
-- 
2.19.1

[for-next][PATCH 16/30] ring-buffer: Add percentage of ring buffer full to wake up reader

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Instead of just waiting for a page to be full before waking up a pending
reader, allow the reader to pass in a "percentage" of pages that have
content before waking up a reader. This should help keep the process of
reading the events not cause wake ups that constantly cause reading of the
buffer.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/linux/ring_buffer.h |  4 ++-
 kernel/trace/ring_buffer.c  | 71 ++++++++++++++++++++++++++++++++++---
 kernel/trace/trace.c        |  8 ++---
 3 files changed, 73 insertions(+), 10 deletions(-)

diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index 0940fda59872..5b9ae62272bb 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -97,7 +97,7 @@ __ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *k
 	__ring_buffer_alloc((size), (flags), &__key);	\
 })
 
-int ring_buffer_wait(struct ring_buffer *buffer, int cpu, bool full);
+int ring_buffer_wait(struct ring_buffer *buffer, int cpu, int full);
 __poll_t ring_buffer_poll_wait(struct ring_buffer *buffer, int cpu,
 			  struct file *filp, poll_table *poll_table);
 
@@ -189,6 +189,8 @@ bool ring_buffer_time_stamp_abs(struct ring_buffer *buffer);
 
 size_t ring_buffer_page_len(void *page);
 
+size_t ring_buffer_nr_pages(struct ring_buffer *buffer, int cpu);
+size_t ring_buffer_nr_dirty_pages(struct ring_buffer *buffer, int cpu);
 
 void *ring_buffer_alloc_read_page(struct ring_buffer *buffer, int cpu);
 void ring_buffer_free_read_page(struct ring_buffer *buffer, int cpu, void *data);
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 65bd4616220d..9edb628603ab 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -487,6 +487,9 @@ struct ring_buffer_per_cpu {
 	local_t				dropped_events;
 	local_t				committing;
 	local_t				commits;
+	local_t				pages_touched;
+	local_t				pages_read;
+	size_t				shortest_full;
 	unsigned long			read;
 	unsigned long			read_bytes;
 	u64				write_stamp;
@@ -529,6 +532,41 @@ struct ring_buffer_iter {
 	u64				read_stamp;
 };
 
+/**
+ * ring_buffer_nr_pages - get the number of buffer pages in the ring buffer
+ * @buffer: The ring_buffer to get the number of pages from
+ * @cpu: The cpu of the ring_buffer to get the number of pages from
+ *
+ * Returns the number of pages used by a per_cpu buffer of the ring buffer.
+ */
+size_t ring_buffer_nr_pages(struct ring_buffer *buffer, int cpu)
+{
+	return buffer->buffers[cpu]->nr_pages;
+}
+
+/**
+ * ring_buffer_nr_pages_dirty - get the number of used pages in the ring buffer
+ * @buffer: The ring_buffer to get the number of pages from
+ * @cpu: The cpu of the ring_buffer to get the number of pages from
+ *
+ * Returns the number of pages that have content in the ring buffer.
+ */
+size_t ring_buffer_nr_dirty_pages(struct ring_buffer *buffer, int cpu)
+{
+	size_t read;
+	size_t cnt;
+
+	read = local_read(&buffer->buffers[cpu]->pages_read);
+	cnt = local_read(&buffer->buffers[cpu]->pages_touched);
+	/* The reader can read an empty page, but not more than that */
+	if (cnt < read) {
+		WARN_ON_ONCE(read > cnt + 1);
+		return 0;
+	}
+
+	return cnt - read;
+}
+
 /*
  * rb_wake_up_waiters - wake up tasks waiting for ring buffer input
  *
@@ -556,7 +594,7 @@ static void rb_wake_up_waiters(struct irq_work *work)
  * as data is added to any of the @buffer's cpu buffers. Otherwise
  * it will wait for data to be added to a specific cpu buffer.
  */
-int ring_buffer_wait(struct ring_buffer *buffer, int cpu, bool full)
+int ring_buffer_wait(struct ring_buffer *buffer, int cpu, int full)
 {
 	struct ring_buffer_per_cpu *uninitialized_var(cpu_buffer);
 	DEFINE_WAIT(wait);
@@ -571,7 +609,7 @@ int ring_buffer_wait(struct ring_buffer *buffer, int cpu, bool full)
 	if (cpu == RING_BUFFER_ALL_CPUS) {
 		work = &buffer->irq_work;
 		/* Full only makes sense on per cpu reads */
-		full = false;
+		full = 0;
 	} else {
 		if (!cpumask_test_cpu(cpu, buffer->cpumask))
 			return -ENODEV;
@@ -623,15 +661,22 @@ int ring_buffer_wait(struct ring_buffer *buffer, int cpu, bool full)
 		    !ring_buffer_empty_cpu(buffer, cpu)) {
 			unsigned long flags;
 			bool pagebusy;
+			size_t nr_pages;
+			size_t dirty;
 
 			if (!full)
 				break;
 
 			raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
 			pagebusy = cpu_buffer->reader_page == cpu_buffer->commit_page;
+			nr_pages = cpu_buffer->nr_pages;
+			dirty = ring_buffer_nr_dirty_pages(buffer, cpu);
+			if (!cpu_buffer->shortest_full ||
+			    cpu_buffer->shortest_full < full)
+				cpu_buffer->shortest_full = full;
 			raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
-
-			if (!pagebusy)
+			if (!pagebusy &&
+			    (!nr_pages || (dirty * 100) > full * nr_pages))
 				break;
 		}
 
@@ -1054,6 +1099,7 @@ static void rb_tail_page_update(struct ring_buffer_per_cpu *cpu_buffer,
 	old_write = local_add_return(RB_WRITE_INTCNT, &next_page->write);
 	old_entries = local_add_return(RB_WRITE_INTCNT, &next_page->entries);
 
+	local_inc(&cpu_buffer->pages_touched);
 	/*
 	 * Just make sure we have seen our old_write and synchronize
 	 * with any interrupts that come in.
@@ -2603,6 +2649,16 @@ rb_wakeups(struct ring_buffer *buffer, struct ring_buffer_per_cpu *cpu_buffer)
 	pagebusy = cpu_buffer->reader_page == cpu_buffer->commit_page;
 
 	if (!pagebusy && cpu_buffer->irq_work.full_waiters_pending) {
+		size_t nr_pages;
+		size_t dirty;
+		size_t full;
+
+		full = cpu_buffer->shortest_full;
+		nr_pages = cpu_buffer->nr_pages;
+		dirty = ring_buffer_nr_dirty_pages(buffer, cpu_buffer->cpu);
+		if (full && nr_pages && (dirty * 100) <= full * nr_pages)
+			return;
+
 		cpu_buffer->irq_work.wakeup_full = true;
 		cpu_buffer->irq_work.full_waiters_pending = false;
 		/* irq_work_queue() supplies it's own memory barriers */
@@ -3732,13 +3788,15 @@ rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer)
 		goto spin;
 
 	/*
-	 * Yeah! We succeeded in replacing the page.
+	 * Yay! We succeeded in replacing the page.
 	 *
 	 * Now make the new head point back to the reader page.
 	 */
 	rb_list_head(reader->list.next)->prev = &cpu_buffer->reader_page->list;
 	rb_inc_page(cpu_buffer, &cpu_buffer->head_page);
 
+	local_inc(&cpu_buffer->pages_read);
+
 	/* Finally update the reader page to the new head */
 	cpu_buffer->reader_page = reader;
 	cpu_buffer->reader_page->read = 0;
@@ -4334,6 +4392,9 @@ rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer)
 	local_set(&cpu_buffer->entries, 0);
 	local_set(&cpu_buffer->committing, 0);
 	local_set(&cpu_buffer->commits, 0);
+	local_set(&cpu_buffer->pages_touched, 0);
+	local_set(&cpu_buffer->pages_read, 0);
+	cpu_buffer->shortest_full = 0;
 	cpu_buffer->read = 0;
 	cpu_buffer->read_bytes = 0;
 
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index ff1c4b20cd0a..48d5eb22ff33 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1431,7 +1431,7 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
 }
 #endif /* CONFIG_TRACER_MAX_TRACE */
 
-static int wait_on_pipe(struct trace_iterator *iter, bool full)
+static int wait_on_pipe(struct trace_iterator *iter, int full)
 {
 	/* Iterators are static, they should be filled or empty */
 	if (trace_buffer_iter(iter, iter->cpu_file))
@@ -5693,7 +5693,7 @@ static int tracing_wait_pipe(struct file *filp)
 
 		mutex_unlock(&iter->mutex);
 
-		ret = wait_on_pipe(iter, false);
+		ret = wait_on_pipe(iter, 0);
 
 		mutex_lock(&iter->mutex);
 
@@ -6751,7 +6751,7 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
 			if ((filp->f_flags & O_NONBLOCK))
 				return -EAGAIN;
 
-			ret = wait_on_pipe(iter, false);
+			ret = wait_on_pipe(iter, 0);
 			if (ret)
 				return ret;
 
@@ -6948,7 +6948,7 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
 		if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
 			goto out;
 
-		ret = wait_on_pipe(iter, true);
+		ret = wait_on_pipe(iter, 1);
 		if (ret)
 			goto out;
 
-- 
2.19.1

[for-next][PATCH 17/30] tracing: Add tracefs file buffer_percentage

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Add a "buffer_percentage" file, that allows users to specify how much of the
buffer (percentage of pages) need to be filled before waking up a task
blocked on a per cpu trace_pipe_raw file.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/ring_buffer.c | 39 ++++++++++++++++-----------
 kernel/trace/trace.c       | 54 +++++++++++++++++++++++++++++++++++++-
 kernel/trace/trace.h       |  1 +
 3 files changed, 77 insertions(+), 17 deletions(-)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 9edb628603ab..5434c16f2192 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -489,6 +489,7 @@ struct ring_buffer_per_cpu {
 	local_t				commits;
 	local_t				pages_touched;
 	local_t				pages_read;
+	long				last_pages_touch;
 	size_t				shortest_full;
 	unsigned long			read;
 	unsigned long			read_bytes;
@@ -2632,7 +2633,9 @@ static void rb_commit(struct ring_buffer_per_cpu *cpu_buffer,
 static __always_inline void
 rb_wakeups(struct ring_buffer *buffer, struct ring_buffer_per_cpu *cpu_buffer)
 {
-	bool pagebusy;
+	size_t nr_pages;
+	size_t dirty;
+	size_t full;
 
 	if (buffer->irq_work.waiters_pending) {
 		buffer->irq_work.waiters_pending = false;
@@ -2646,24 +2649,27 @@ rb_wakeups(struct ring_buffer *buffer, struct ring_buffer_per_cpu *cpu_buffer)
 		irq_work_queue(&cpu_buffer->irq_work.work);
 	}
 
-	pagebusy = cpu_buffer->reader_page == cpu_buffer->commit_page;
+	if (cpu_buffer->last_pages_touch == local_read(&cpu_buffer->pages_touched))
+		return;
 
-	if (!pagebusy && cpu_buffer->irq_work.full_waiters_pending) {
-		size_t nr_pages;
-		size_t dirty;
-		size_t full;
+	if (cpu_buffer->reader_page == cpu_buffer->commit_page)
+		return;
 
-		full = cpu_buffer->shortest_full;
-		nr_pages = cpu_buffer->nr_pages;
-		dirty = ring_buffer_nr_dirty_pages(buffer, cpu_buffer->cpu);
-		if (full && nr_pages && (dirty * 100) <= full * nr_pages)
-			return;
+	if (!cpu_buffer->irq_work.full_waiters_pending)
+		return;
 
-		cpu_buffer->irq_work.wakeup_full = true;
-		cpu_buffer->irq_work.full_waiters_pending = false;
-		/* irq_work_queue() supplies it's own memory barriers */
-		irq_work_queue(&cpu_buffer->irq_work.work);
-	}
+	cpu_buffer->last_pages_touch = local_read(&cpu_buffer->pages_touched);
+
+	full = cpu_buffer->shortest_full;
+	nr_pages = cpu_buffer->nr_pages;
+	dirty = ring_buffer_nr_dirty_pages(buffer, cpu_buffer->cpu);
+	if (full && nr_pages && (dirty * 100) <= full * nr_pages)
+		return;
+
+	cpu_buffer->irq_work.wakeup_full = true;
+	cpu_buffer->irq_work.full_waiters_pending = false;
+	/* irq_work_queue() supplies it's own memory barriers */
+	irq_work_queue(&cpu_buffer->irq_work.work);
 }
 
 /*
@@ -4394,6 +4400,7 @@ rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer)
 	local_set(&cpu_buffer->commits, 0);
 	local_set(&cpu_buffer->pages_touched, 0);
 	local_set(&cpu_buffer->pages_read, 0);
+	cpu_buffer->last_pages_touch = 0;
 	cpu_buffer->shortest_full = 0;
 	cpu_buffer->read = 0;
 	cpu_buffer->read_bytes = 0;
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 48d5eb22ff33..d382fd1aa4a6 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6948,7 +6948,7 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
 		if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
 			goto out;
 
-		ret = wait_on_pipe(iter, 1);
+		ret = wait_on_pipe(iter, iter->tr->buffer_percent);
 		if (ret)
 			goto out;
 
@@ -7662,6 +7662,53 @@ static const struct file_operations rb_simple_fops = {
 	.llseek		= default_llseek,
 };
 
+static ssize_t
+buffer_percent_read(struct file *filp, char __user *ubuf,
+		    size_t cnt, loff_t *ppos)
+{
+	struct trace_array *tr = filp->private_data;
+	char buf[64];
+	int r;
+
+	r = tr->buffer_percent;
+	r = sprintf(buf, "%d\n", r);
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+buffer_percent_write(struct file *filp, const char __user *ubuf,
+		     size_t cnt, loff_t *ppos)
+{
+	struct trace_array *tr = filp->private_data;
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
+		return ret;
+
+	if (val > 100)
+		return -EINVAL;
+
+	if (!val)
+		val = 1;
+
+	tr->buffer_percent = val;
+
+	(*ppos)++;
+
+	return cnt;
+}
+
+static const struct file_operations buffer_percent_fops = {
+	.open		= tracing_open_generic_tr,
+	.read		= buffer_percent_read,
+	.write		= buffer_percent_write,
+	.release	= tracing_release_generic_tr,
+	.llseek		= default_llseek,
+};
+
 struct dentry *trace_instance_dir;
 
 static void
@@ -7970,6 +8017,11 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
 	trace_create_file("timestamp_mode", 0444, d_tracer, tr,
 			  &trace_time_stamp_mode_fops);
 
+	tr->buffer_percent = 1;
+
+	trace_create_file("buffer_percent", 0444, d_tracer,
+			tr, &buffer_percent_fops);
+
 	create_trace_options_dir(tr);
 
 #if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index ab16eca76e59..08900828d282 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -247,6 +247,7 @@ struct trace_array {
 	int			clock_id;
 	int			nr_topts;
 	bool			clear_trace;
+	int			buffer_percent;
 	struct tracer		*current_trace;
 	unsigned int		trace_flags;
 	unsigned char		trace_flags_index[TRACE_FLAGS_MAX_SIZE];
-- 
2.19.1

[for-next][PATCH 18/30] tracing: Change default buffer_percent to 50

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

After running several tests, it appears that having the reader wait till
half the buffer is full before starting to read (and causing its own events
to fill up the ring buffer constantly), works well. It keeps trace-cmd (the
main user of this interface) from dominating the traces it records.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index d382fd1aa4a6..194c01838e3f 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -8017,7 +8017,7 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
 	trace_create_file("timestamp_mode", 0444, d_tracer, tr,
 			  &trace_time_stamp_mode_fops);
 
-	tr->buffer_percent = 1;
+	tr->buffer_percent = 50;
 
 	trace_create_file("buffer_percent", 0444, d_tracer,
 			tr, &buffer_percent_fops);
-- 
2.19.1

[for-next][PATCH 19/30] tracing/uprobes: Add busy check when cleanup all uprobes

[Steven Rostedt]

From: Masami Hiramatsu <mhiramat@kernel.org>

Add a busy check loop in cleanup_all_probes() before
trying to remove all events in uprobe_events, the same way
that kprobe_events does.

Without this change, writing null to uprobe_events will
try to remove events but if one of them is enabled, it will
stop there leaving some events cleared and others not clceared.

With this change, writing null to uprobe_events makes
sure all events are not enabled before removing events.
So, it clears all events, or returns an error (-EBUSY)
with keeping all events.

Link: http://lkml.kernel.org/r/154140841557.17322.12653952888762532401.stgit@devbox

Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_uprobe.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 31ea48eceda1..b708e4ff7ea7 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -587,12 +587,19 @@ static int cleanup_all_probes(void)
 	int ret = 0;
 
 	mutex_lock(&uprobe_lock);
+	/* Ensure no probe is in use. */
+	list_for_each_entry(tu, &uprobe_list, list)
+		if (trace_probe_is_enabled(&tu->tp)) {
+			ret = -EBUSY;
+			goto end;
+		}
 	while (!list_empty(&uprobe_list)) {
 		tu = list_entry(uprobe_list.next, struct trace_uprobe, list);
 		ret = unregister_trace_uprobe(tu);
 		if (ret)
 			break;
 	}
+end:
 	mutex_unlock(&uprobe_lock);
 	return ret;
 }
-- 
2.19.1

[for-next][PATCH 20/30] tracing: Lock event_mutex before synth_event_mutex

[Steven Rostedt]

From: Masami Hiramatsu <mhiramat@kernel.org>

synthetic event is using synth_event_mutex for protecting
synth_event_list, and event_trigger_write() path acquires
locks as below order.

event_trigger_write(event_mutex)
  ->trigger_process_regex(trigger_cmd_mutex)
    ->event_hist_trigger_func(synth_event_mutex)

On the other hand, synthetic event creation and deletion paths
call trace_add_event_call() and trace_remove_event_call()
which acquires event_mutex. In that case, if we keep the
synth_event_mutex locked while registering/unregistering synthetic
events, its dependency will be inversed.

To avoid this issue, current synthetic event is using a 2 phase
process to create/delete events. For example, it searches existing
events under synth_event_mutex to check for event-name conflicts, and
unlocks synth_event_mutex, then registers a new event under event_mutex
locked. Finally, it locks synth_event_mutex and tries to add the
new event to the list. But it can introduce complexity and a chance
for name conflicts.

To solve this simpler, this introduces trace_add_event_call_nolock()
and trace_remove_event_call_nolock() which don't acquire
event_mutex inside. synthetic event can lock event_mutex before
synth_event_mutex to solve the lock dependency issue simpler.

Link: http://lkml.kernel.org/r/154140844377.17322.13781091165954002713.stgit@devbox

Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/linux/trace_events.h     |  2 ++
 kernel/trace/trace_events.c      | 34 ++++++++++++++++++++++++++------
 kernel/trace/trace_events_hist.c | 24 ++++++++++------------
 3 files changed, 40 insertions(+), 20 deletions(-)

diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 4130a5497d40..3aa05593a53f 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -529,6 +529,8 @@ extern int trace_event_raw_init(struct trace_event_call *call);
 extern int trace_define_field(struct trace_event_call *call, const char *type,
 			      const char *name, int offset, int size,
 			      int is_signed, int filter_type);
+extern int trace_add_event_call_nolock(struct trace_event_call *call);
+extern int trace_remove_event_call_nolock(struct trace_event_call *call);
 extern int trace_add_event_call(struct trace_event_call *call);
 extern int trace_remove_event_call(struct trace_event_call *call);
 extern int trace_event_get_offsets(struct trace_event_call *call);
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index f94be0c2827b..a3b157f689ee 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2305,11 +2305,11 @@ __trace_early_add_new_event(struct trace_event_call *call,
 struct ftrace_module_file_ops;
 static void __add_event_to_tracers(struct trace_event_call *call);
 
-/* Add an additional event_call dynamically */
-int trace_add_event_call(struct trace_event_call *call)
+int trace_add_event_call_nolock(struct trace_event_call *call)
 {
 	int ret;
-	mutex_lock(&event_mutex);
+	lockdep_assert_held(&event_mutex);
+
 	mutex_lock(&trace_types_lock);
 
 	ret = __register_event(call, NULL);
@@ -2317,6 +2317,16 @@ int trace_add_event_call(struct trace_event_call *call)
 		__add_event_to_tracers(call);
 
 	mutex_unlock(&trace_types_lock);
+	return ret;
+}
+
+/* Add an additional event_call dynamically */
+int trace_add_event_call(struct trace_event_call *call)
+{
+	int ret;
+
+	mutex_lock(&event_mutex);
+	ret = trace_add_event_call_nolock(call);
 	mutex_unlock(&event_mutex);
 	return ret;
 }
@@ -2366,17 +2376,29 @@ static int probe_remove_event_call(struct trace_event_call *call)
 	return 0;
 }
 
-/* Remove an event_call */
-int trace_remove_event_call(struct trace_event_call *call)
+/* no event_mutex version */
+int trace_remove_event_call_nolock(struct trace_event_call *call)
 {
 	int ret;
 
-	mutex_lock(&event_mutex);
+	lockdep_assert_held(&event_mutex);
+
 	mutex_lock(&trace_types_lock);
 	down_write(&trace_event_sem);
 	ret = probe_remove_event_call(call);
 	up_write(&trace_event_sem);
 	mutex_unlock(&trace_types_lock);
+
+	return ret;
+}
+
+/* Remove an event_call */
+int trace_remove_event_call(struct trace_event_call *call)
+{
+	int ret;
+
+	mutex_lock(&event_mutex);
+	ret = trace_remove_event_call_nolock(call);
 	mutex_unlock(&event_mutex);
 
 	return ret;
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index eb908ef2ecec..1670c65389fe 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -912,7 +912,7 @@ static int register_synth_event(struct synth_event *event)
 	call->data = event;
 	call->tp = event->tp;
 
-	ret = trace_add_event_call(call);
+	ret = trace_add_event_call_nolock(call);
 	if (ret) {
 		pr_warn("Failed to register synthetic event: %s\n",
 			trace_event_name(call));
@@ -936,7 +936,7 @@ static int unregister_synth_event(struct synth_event *event)
 	struct trace_event_call *call = &event->call;
 	int ret;
 
-	ret = trace_remove_event_call(call);
+	ret = trace_remove_event_call_nolock(call);
 
 	return ret;
 }
@@ -1013,12 +1013,10 @@ static void add_or_delete_synth_event(struct synth_event *event, int delete)
 	if (delete)
 		free_synth_event(event);
 	else {
-		mutex_lock(&synth_event_mutex);
 		if (!find_synth_event(event->name))
 			list_add(&event->list, &synth_event_list);
 		else
 			free_synth_event(event);
-		mutex_unlock(&synth_event_mutex);
 	}
 }
 
@@ -1030,6 +1028,7 @@ static int create_synth_event(int argc, char **argv)
 	int i, consumed = 0, n_fields = 0, ret = 0;
 	char *name;
 
+	mutex_lock(&event_mutex);
 	mutex_lock(&synth_event_mutex);
 
 	/*
@@ -1102,8 +1101,6 @@ static int create_synth_event(int argc, char **argv)
 		goto err;
 	}
  out:
-	mutex_unlock(&synth_event_mutex);
-
 	if (event) {
 		if (delete_event) {
 			ret = unregister_synth_event(event);
@@ -1113,10 +1110,13 @@ static int create_synth_event(int argc, char **argv)
 			add_or_delete_synth_event(event, ret);
 		}
 	}
+	mutex_unlock(&synth_event_mutex);
+	mutex_unlock(&event_mutex);
 
 	return ret;
  err:
 	mutex_unlock(&synth_event_mutex);
+	mutex_unlock(&event_mutex);
 
 	for (i = 0; i < n_fields; i++)
 		free_synth_field(fields[i]);
@@ -1127,12 +1127,10 @@ static int create_synth_event(int argc, char **argv)
 
 static int release_all_synth_events(void)
 {
-	struct list_head release_events;
 	struct synth_event *event, *e;
 	int ret = 0;
 
-	INIT_LIST_HEAD(&release_events);
-
+	mutex_lock(&event_mutex);
 	mutex_lock(&synth_event_mutex);
 
 	list_for_each_entry(event, &synth_event_list, list) {
@@ -1142,16 +1140,14 @@ static int release_all_synth_events(void)
 		}
 	}
 
-	list_splice_init(&event->list, &release_events);
-
-	mutex_unlock(&synth_event_mutex);
-
-	list_for_each_entry_safe(event, e, &release_events, list) {
+	list_for_each_entry_safe(event, e, &synth_event_list, list) {
 		list_del(&event->list);
 
 		ret = unregister_synth_event(event);
 		add_or_delete_synth_event(event, !ret);
 	}
+	mutex_unlock(&synth_event_mutex);
+	mutex_unlock(&event_mutex);
 
 	return ret;
 }
-- 
2.19.1

[for-next][PATCH 21/30] tracing: Simplify creation and deletion of synthetic events

[Steven Rostedt]

From: Masami Hiramatsu <mhiramat@kernel.org>

Since the event_mutex and synth_event_mutex ordering issue
is gone, we can skip existing event check when adding or
deleting events, and some redundant code in error path.

This changes release_all_synth_events() to abort the process
when it hits any error and returns the error code. It succeeds
only if it has no error.

Link: http://lkml.kernel.org/r/154140847194.17322.17960275728005067803.stgit@devbox

Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_events_hist.c | 53 +++++++++++---------------------
 1 file changed, 18 insertions(+), 35 deletions(-)

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 1670c65389fe..0feb7f460123 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -1008,18 +1008,6 @@ struct hist_var_data {
 	struct hist_trigger_data *hist_data;
 };
 
-static void add_or_delete_synth_event(struct synth_event *event, int delete)
-{
-	if (delete)
-		free_synth_event(event);
-	else {
-		if (!find_synth_event(event->name))
-			list_add(&event->list, &synth_event_list);
-		else
-			free_synth_event(event);
-	}
-}
-
 static int create_synth_event(int argc, char **argv)
 {
 	struct synth_field *field, *fields[SYNTH_FIELDS_MAX];
@@ -1052,15 +1040,16 @@ static int create_synth_event(int argc, char **argv)
 	if (event) {
 		if (delete_event) {
 			if (event->ref) {
-				event = NULL;
 				ret = -EBUSY;
 				goto out;
 			}
-			list_del(&event->list);
-			goto out;
-		}
-		event = NULL;
-		ret = -EEXIST;
+			ret = unregister_synth_event(event);
+			if (!ret) {
+				list_del(&event->list);
+				free_synth_event(event);
+			}
+		} else
+			ret = -EEXIST;
 		goto out;
 	} else if (delete_event) {
 		ret = -ENOENT;
@@ -1100,29 +1089,21 @@ static int create_synth_event(int argc, char **argv)
 		event = NULL;
 		goto err;
 	}
+	ret = register_synth_event(event);
+	if (!ret)
+		list_add(&event->list, &synth_event_list);
+	else
+		free_synth_event(event);
  out:
-	if (event) {
-		if (delete_event) {
-			ret = unregister_synth_event(event);
-			add_or_delete_synth_event(event, !ret);
-		} else {
-			ret = register_synth_event(event);
-			add_or_delete_synth_event(event, ret);
-		}
-	}
 	mutex_unlock(&synth_event_mutex);
 	mutex_unlock(&event_mutex);
 
 	return ret;
  err:
-	mutex_unlock(&synth_event_mutex);
-	mutex_unlock(&event_mutex);
-
 	for (i = 0; i < n_fields; i++)
 		free_synth_field(fields[i]);
-	free_synth_event(event);
 
-	return ret;
+	goto out;
 }
 
 static int release_all_synth_events(void)
@@ -1141,10 +1122,12 @@ static int release_all_synth_events(void)
 	}
 
 	list_for_each_entry_safe(event, e, &synth_event_list, list) {
-		list_del(&event->list);
-
 		ret = unregister_synth_event(event);
-		add_or_delete_synth_event(event, !ret);
+		if (!ret) {
+			list_del(&event->list);
+			free_synth_event(event);
+		} else
+			break;
 	}
 	mutex_unlock(&synth_event_mutex);
 	mutex_unlock(&event_mutex);
-- 
2.19.1

[for-next][PATCH 22/30] tracing: Integrate similar probe argument parsers

[Steven Rostedt]

From: Masami Hiramatsu <mhiramat@kernel.org>

Integrate similar argument parsers for kprobes and uprobes events
into traceprobe_parse_probe_arg().

Link: http://lkml.kernel.org/r/154140850016.17322.9836787731210512176.stgit@devbox

Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_kprobe.c | 48 ++-----------------------------------
 kernel/trace/trace_probe.c  | 47 +++++++++++++++++++++++++++++++++---
 kernel/trace/trace_probe.h  |  7 ++----
 kernel/trace/trace_uprobe.c | 44 ++--------------------------------
 4 files changed, 50 insertions(+), 96 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index fec67188c4d2..d313bcc259dc 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -548,7 +548,6 @@ static int create_trace_kprobe(int argc, char **argv)
 	bool is_return = false, is_delete = false;
 	char *symbol = NULL, *event = NULL, *group = NULL;
 	int maxactive = 0;
-	char *arg;
 	long offset = 0;
 	void *addr = NULL;
 	char buf[MAX_EVENT_NAME_LEN];
@@ -676,53 +675,10 @@ static int create_trace_kprobe(int argc, char **argv)
 	}
 
 	/* parse arguments */
-	ret = 0;
 	for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
-		struct probe_arg *parg = &tk->tp.args[i];
-
-		/* Increment count for freeing args in error case */
-		tk->tp.nr_args++;
-
-		/* Parse argument name */
-		arg = strchr(argv[i], '=');
-		if (arg) {
-			*arg++ = '\0';
-			parg->name = kstrdup(argv[i], GFP_KERNEL);
-		} else {
-			arg = argv[i];
-			/* If argument name is omitted, set "argN" */
-			snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
-			parg->name = kstrdup(buf, GFP_KERNEL);
-		}
-
-		if (!parg->name) {
-			pr_info("Failed to allocate argument[%d] name.\n", i);
-			ret = -ENOMEM;
-			goto error;
-		}
-
-		if (!is_good_name(parg->name)) {
-			pr_info("Invalid argument[%d] name: %s\n",
-				i, parg->name);
-			ret = -EINVAL;
-			goto error;
-		}
-
-		if (traceprobe_conflict_field_name(parg->name,
-							tk->tp.args, i)) {
-			pr_info("Argument[%d] name '%s' conflicts with "
-				"another field.\n", i, argv[i]);
-			ret = -EINVAL;
-			goto error;
-		}
-
-		/* Parse fetch argument */
-		ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
-						 flags);
-		if (ret) {
-			pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
+		ret = traceprobe_parse_probe_arg(&tk->tp, i, argv[i], flags);
+		if (ret)
 			goto error;
-		}
 	}
 
 	ret = register_trace_kprobe(tk);
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index bd30e9398d2a..449150c6a87f 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -348,7 +348,7 @@ static int __parse_bitfield_probe_arg(const char *bf,
 }
 
 /* String length checking wrapper */
-int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
+static int traceprobe_parse_probe_arg_body(char *arg, ssize_t *size,
 		struct probe_arg *parg, unsigned int flags)
 {
 	struct fetch_insn *code, *scode, *tmp = NULL;
@@ -491,8 +491,8 @@ int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
 }
 
 /* Return 1 if name is reserved or already used by another argument */
-int traceprobe_conflict_field_name(const char *name,
-			       struct probe_arg *args, int narg)
+static int traceprobe_conflict_field_name(const char *name,
+					  struct probe_arg *args, int narg)
 {
 	int i;
 
@@ -507,6 +507,47 @@ int traceprobe_conflict_field_name(const char *name,
 	return 0;
 }
 
+int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, char *arg,
+				unsigned int flags)
+{
+	struct probe_arg *parg = &tp->args[i];
+	char *body;
+	int ret;
+
+	/* Increment count for freeing args in error case */
+	tp->nr_args++;
+
+	body = strchr(arg, '=');
+	if (body) {
+		parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL);
+		body++;
+	} else {
+		/* If argument name is omitted, set "argN" */
+		parg->name = kasprintf(GFP_KERNEL, "arg%d", i + 1);
+		body = arg;
+	}
+	if (!parg->name)
+		return -ENOMEM;
+
+	if (!is_good_name(parg->name)) {
+		pr_info("Invalid argument[%d] name: %s\n",
+			i, parg->name);
+		return -EINVAL;
+	}
+
+	if (traceprobe_conflict_field_name(parg->name, tp->args, i)) {
+		pr_info("Argument[%d]: '%s' conflicts with another field.\n",
+			i, parg->name);
+		return -EINVAL;
+	}
+
+	/* Parse fetch argument */
+	ret = traceprobe_parse_probe_arg_body(body, &tp->size, parg, flags);
+	if (ret)
+		pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
+	return ret;
+}
+
 void traceprobe_free_probe_arg(struct probe_arg *arg)
 {
 	struct fetch_insn *code = arg->code;
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 974afc1a3e73..feeec261b356 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -272,11 +272,8 @@ find_event_file_link(struct trace_probe *tp, struct trace_event_file *file)
 #define TPARG_FL_FENTRY BIT(2)
 #define TPARG_FL_MASK	GENMASK(2, 0)
 
-extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
-		   struct probe_arg *parg, unsigned int flags);
-
-extern int traceprobe_conflict_field_name(const char *name,
-			       struct probe_arg *args, int narg);
+extern int traceprobe_parse_probe_arg(struct trace_probe *tp, int i,
+				char *arg, unsigned int flags);
 
 extern int traceprobe_update_arg(struct probe_arg *arg);
 extern void traceprobe_free_probe_arg(struct probe_arg *arg);
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index b708e4ff7ea7..6eaaa2150685 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -517,51 +517,11 @@ static int create_trace_uprobe(int argc, char **argv)
 	}
 
 	/* parse arguments */
-	ret = 0;
 	for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
-		struct probe_arg *parg = &tu->tp.args[i];
-
-		/* Increment count for freeing args in error case */
-		tu->tp.nr_args++;
-
-		/* Parse argument name */
-		arg = strchr(argv[i], '=');
-		if (arg) {
-			*arg++ = '\0';
-			parg->name = kstrdup(argv[i], GFP_KERNEL);
-		} else {
-			arg = argv[i];
-			/* If argument name is omitted, set "argN" */
-			snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
-			parg->name = kstrdup(buf, GFP_KERNEL);
-		}
-
-		if (!parg->name) {
-			pr_info("Failed to allocate argument[%d] name.\n", i);
-			ret = -ENOMEM;
-			goto error;
-		}
-
-		if (!is_good_name(parg->name)) {
-			pr_info("Invalid argument[%d] name: %s\n", i, parg->name);
-			ret = -EINVAL;
-			goto error;
-		}
-
-		if (traceprobe_conflict_field_name(parg->name, tu->tp.args, i)) {
-			pr_info("Argument[%d] name '%s' conflicts with "
-				"another field.\n", i, argv[i]);
-			ret = -EINVAL;
-			goto error;
-		}
-
-		/* Parse fetch argument */
-		ret = traceprobe_parse_probe_arg(arg, &tu->tp.size, parg,
+		ret = traceprobe_parse_probe_arg(&tu->tp, i, argv[i],
 					is_return ? TPARG_FL_RETURN : 0);
-		if (ret) {
-			pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
+		if (ret)
 			goto error;
-		}
 	}
 
 	ret = register_trace_uprobe(tu);
-- 
2.19.1

[for-next][PATCH 23/30] tracing: Add unified dynamic event framework

[Steven Rostedt]

From: Masami Hiramatsu <mhiramat@kernel.org>

Add unified dynamic event framework for ftrace kprobes, uprobes
and synthetic events. Those dynamic events can be co-exist on
same file because those syntax doesn't overlap.

This introduces a framework part which provides a unified tracefs
interface and operations.

Link: http://lkml.kernel.org/r/154140852824.17322.12250362185969352095.stgit@devbox

Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/Kconfig          |   3 +
 kernel/trace/Makefile         |   1 +
 kernel/trace/trace.c          |   4 +
 kernel/trace/trace_dynevent.c | 210 ++++++++++++++++++++++++++++++++++
 kernel/trace/trace_dynevent.h | 119 +++++++++++++++++++
 5 files changed, 337 insertions(+)
 create mode 100644 kernel/trace/trace_dynevent.c
 create mode 100644 kernel/trace/trace_dynevent.h

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 5e3de28c7677..bf2e8a5a91f1 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -518,6 +518,9 @@ config BPF_EVENTS
 	help
 	  This allows the user to attach BPF programs to kprobe events.
 
+config DYNAMIC_EVENTS
+	def_bool n
+
 config PROBE_EVENTS
 	def_bool n
 
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index c7ade7965464..c2b2148bb1d2 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -79,6 +79,7 @@ endif
 ifeq ($(CONFIG_TRACING),y)
 obj-$(CONFIG_KGDB_KDB) += trace_kdb.o
 endif
+obj-$(CONFIG_DYNAMIC_EVENTS) += trace_dynevent.o
 obj-$(CONFIG_PROBE_EVENTS) += trace_probe.o
 obj-$(CONFIG_UPROBE_EVENTS) += trace_uprobe.o
 
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 194c01838e3f..7e0332f90ed4 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4604,6 +4604,10 @@ static const char readme_msg[] =
 	"\t\t\t  traces\n"
 #endif
 #endif /* CONFIG_STACK_TRACER */
+#ifdef CONFIG_DYNAMIC_EVENTS
+	"  dynamic_events\t\t- Add/remove/show the generic dynamic events\n"
+	"\t\t\t  Write into this file to define/undefine new trace events.\n"
+#endif
 #ifdef CONFIG_KPROBE_EVENTS
 	"  kprobe_events\t\t- Add/remove/show the kernel dynamic events\n"
 	"\t\t\t  Write into this file to define/undefine new trace events.\n"
diff --git a/kernel/trace/trace_dynevent.c b/kernel/trace/trace_dynevent.c
new file mode 100644
index 000000000000..f17a887abb66
--- /dev/null
+++ b/kernel/trace/trace_dynevent.c
@@ -0,0 +1,210 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generic dynamic event control interface
+ *
+ * Copyright (C) 2018 Masami Hiramatsu <mhiramat@kernel.org>
+ */
+
+#include <linux/debugfs.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/mm.h>
+#include <linux/mutex.h>
+#include <linux/tracefs.h>
+
+#include "trace.h"
+#include "trace_dynevent.h"
+
+static DEFINE_MUTEX(dyn_event_ops_mutex);
+static LIST_HEAD(dyn_event_ops_list);
+
+int dyn_event_register(struct dyn_event_operations *ops)
+{
+	if (!ops || !ops->create || !ops->show || !ops->is_busy ||
+	    !ops->free || !ops->match)
+		return -EINVAL;
+
+	INIT_LIST_HEAD(&ops->list);
+	mutex_lock(&dyn_event_ops_mutex);
+	list_add_tail(&ops->list, &dyn_event_ops_list);
+	mutex_unlock(&dyn_event_ops_mutex);
+	return 0;
+}
+
+int dyn_event_release(int argc, char **argv, struct dyn_event_operations *type)
+{
+	struct dyn_event *pos, *n;
+	char *system = NULL, *event, *p;
+	int ret = -ENOENT;
+
+	if (argv[0][1] != ':')
+		return -EINVAL;
+
+	event = &argv[0][2];
+	p = strchr(event, '/');
+	if (p) {
+		system = event;
+		event = p + 1;
+		*p = '\0';
+	}
+	if (event[0] == '\0')
+		return -EINVAL;
+
+	mutex_lock(&event_mutex);
+	for_each_dyn_event_safe(pos, n) {
+		if (type && type != pos->ops)
+			continue;
+		if (pos->ops->match(system, event, pos)) {
+			ret = pos->ops->free(pos);
+			break;
+		}
+	}
+	mutex_unlock(&event_mutex);
+
+	return ret;
+}
+
+static int create_dyn_event(int argc, char **argv)
+{
+	struct dyn_event_operations *ops;
+	int ret;
+
+	if (argv[0][0] == '-')
+		return dyn_event_release(argc, argv, NULL);
+
+	mutex_lock(&dyn_event_ops_mutex);
+	list_for_each_entry(ops, &dyn_event_ops_list, list) {
+		ret = ops->create(argc, (const char **)argv);
+		if (!ret || ret != -ECANCELED)
+			break;
+	}
+	mutex_unlock(&dyn_event_ops_mutex);
+	if (ret == -ECANCELED)
+		ret = -EINVAL;
+
+	return ret;
+}
+
+/* Protected by event_mutex */
+LIST_HEAD(dyn_event_list);
+
+void *dyn_event_seq_start(struct seq_file *m, loff_t *pos)
+{
+	mutex_lock(&event_mutex);
+	return seq_list_start(&dyn_event_list, *pos);
+}
+
+void *dyn_event_seq_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	return seq_list_next(v, &dyn_event_list, pos);
+}
+
+void dyn_event_seq_stop(struct seq_file *m, void *v)
+{
+	mutex_unlock(&event_mutex);
+}
+
+static int dyn_event_seq_show(struct seq_file *m, void *v)
+{
+	struct dyn_event *ev = v;
+
+	if (ev && ev->ops)
+		return ev->ops->show(m, ev);
+
+	return 0;
+}
+
+static const struct seq_operations dyn_event_seq_op = {
+	.start	= dyn_event_seq_start,
+	.next	= dyn_event_seq_next,
+	.stop	= dyn_event_seq_stop,
+	.show	= dyn_event_seq_show
+};
+
+/*
+ * dyn_events_release_all - Release all specific events
+ * @type:	the dyn_event_operations * which filters releasing events
+ *
+ * This releases all events which ->ops matches @type. If @type is NULL,
+ * all events are released.
+ * Return -EBUSY if any of them are in use, and return other errors when
+ * it failed to free the given event. Except for -EBUSY, event releasing
+ * process will be aborted at that point and there may be some other
+ * releasable events on the list.
+ */
+int dyn_events_release_all(struct dyn_event_operations *type)
+{
+	struct dyn_event *ev, *tmp;
+	int ret = 0;
+
+	mutex_lock(&event_mutex);
+	for_each_dyn_event(ev) {
+		if (type && ev->ops != type)
+			continue;
+		if (ev->ops->is_busy(ev)) {
+			ret = -EBUSY;
+			goto out;
+		}
+	}
+	for_each_dyn_event_safe(ev, tmp) {
+		if (type && ev->ops != type)
+			continue;
+		ret = ev->ops->free(ev);
+		if (ret)
+			break;
+	}
+out:
+	mutex_unlock(&event_mutex);
+
+	return ret;
+}
+
+static int dyn_event_open(struct inode *inode, struct file *file)
+{
+	int ret;
+
+	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
+		ret = dyn_events_release_all(NULL);
+		if (ret < 0)
+			return ret;
+	}
+
+	return seq_open(file, &dyn_event_seq_op);
+}
+
+static ssize_t dyn_event_write(struct file *file, const char __user *buffer,
+				size_t count, loff_t *ppos)
+{
+	return trace_parse_run_command(file, buffer, count, ppos,
+				       create_dyn_event);
+}
+
+static const struct file_operations dynamic_events_ops = {
+	.owner          = THIS_MODULE,
+	.open           = dyn_event_open,
+	.read           = seq_read,
+	.llseek         = seq_lseek,
+	.release        = seq_release,
+	.write		= dyn_event_write,
+};
+
+/* Make a tracefs interface for controlling dynamic events */
+static __init int init_dynamic_event(void)
+{
+	struct dentry *d_tracer;
+	struct dentry *entry;
+
+	d_tracer = tracing_init_dentry();
+	if (IS_ERR(d_tracer))
+		return 0;
+
+	entry = tracefs_create_file("dynamic_events", 0644, d_tracer,
+				    NULL, &dynamic_events_ops);
+
+	/* Event list interface */
+	if (!entry)
+		pr_warn("Could not create tracefs 'dynamic_events' entry\n");
+
+	return 0;
+}
+fs_initcall(init_dynamic_event);
diff --git a/kernel/trace/trace_dynevent.h b/kernel/trace/trace_dynevent.h
new file mode 100644
index 000000000000..8c334064e4d6
--- /dev/null
+++ b/kernel/trace/trace_dynevent.h
@@ -0,0 +1,119 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Common header file for generic dynamic events.
+ */
+
+#ifndef _TRACE_DYNEVENT_H
+#define _TRACE_DYNEVENT_H
+
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/seq_file.h>
+
+#include "trace.h"
+
+struct dyn_event;
+
+/**
+ * struct dyn_event_operations - Methods for each type of dynamic events
+ *
+ * These methods must be set for each type, since there is no default method.
+ * Before using this for dyn_event_init(), it must be registered by
+ * dyn_event_register().
+ *
+ * @create: Parse and create event method. This is invoked when user passes
+ *  a event definition to dynamic_events interface. This must not destruct
+ *  the arguments and return -ECANCELED if given arguments doesn't match its
+ *  command prefix.
+ * @show: Showing method. This is invoked when user reads the event definitions
+ *  via dynamic_events interface.
+ * @is_busy: Check whether given event is busy so that it can not be deleted.
+ *  Return true if it is busy, otherwides false.
+ * @free: Delete the given event. Return 0 if success, otherwides error.
+ * @match: Check whether given event and system name match this event.
+ *  Return true if it matches, otherwides false.
+ *
+ * Except for @create, these methods are called under holding event_mutex.
+ */
+struct dyn_event_operations {
+	struct list_head	list;
+	int (*create)(int argc, const char *argv[]);
+	int (*show)(struct seq_file *m, struct dyn_event *ev);
+	bool (*is_busy)(struct dyn_event *ev);
+	int (*free)(struct dyn_event *ev);
+	bool (*match)(const char *system, const char *event,
+			struct dyn_event *ev);
+};
+
+/* Register new dyn_event type -- must be called at first */
+int dyn_event_register(struct dyn_event_operations *ops);
+
+/**
+ * struct dyn_event - Dynamic event list header
+ *
+ * The dyn_event structure encapsulates a list and a pointer to the operators
+ * for making a global list of dynamic events.
+ * User must includes this in each event structure, so that those events can
+ * be added/removed via dynamic_events interface.
+ */
+struct dyn_event {
+	struct list_head		list;
+	struct dyn_event_operations	*ops;
+};
+
+extern struct list_head dyn_event_list;
+
+static inline
+int dyn_event_init(struct dyn_event *ev, struct dyn_event_operations *ops)
+{
+	if (!ev || !ops)
+		return -EINVAL;
+
+	INIT_LIST_HEAD(&ev->list);
+	ev->ops = ops;
+	return 0;
+}
+
+static inline int dyn_event_add(struct dyn_event *ev)
+{
+	lockdep_assert_held(&event_mutex);
+
+	if (!ev || !ev->ops)
+		return -EINVAL;
+
+	list_add_tail(&ev->list, &dyn_event_list);
+	return 0;
+}
+
+static inline void dyn_event_remove(struct dyn_event *ev)
+{
+	lockdep_assert_held(&event_mutex);
+	list_del_init(&ev->list);
+}
+
+void *dyn_event_seq_start(struct seq_file *m, loff_t *pos);
+void *dyn_event_seq_next(struct seq_file *m, void *v, loff_t *pos);
+void dyn_event_seq_stop(struct seq_file *m, void *v);
+int dyn_events_release_all(struct dyn_event_operations *type);
+int dyn_event_release(int argc, char **argv, struct dyn_event_operations *type);
+
+/*
+ * for_each_dyn_event	-	iterate over the dyn_event list
+ * @pos:	the struct dyn_event * to use as a loop cursor
+ *
+ * This is just a basement of for_each macro. Wrap this for
+ * each actual event structure with ops filtering.
+ */
+#define for_each_dyn_event(pos)	\
+	list_for_each_entry(pos, &dyn_event_list, list)
+
+/*
+ * for_each_dyn_event	-	iterate over the dyn_event list safely
+ * @pos:	the struct dyn_event * to use as a loop cursor
+ * @n:		the struct dyn_event * to use as temporary storage
+ */
+#define for_each_dyn_event_safe(pos, n)	\
+	list_for_each_entry_safe(pos, n, &dyn_event_list, list)
+
+#endif
-- 
2.19.1

[for-next][PATCH 24/30] tracing/kprobes: Use dyn_event framework for kprobe events

[Steven Rostedt]

From: Masami Hiramatsu <mhiramat@kernel.org>

Use dyn_event framework for kprobe events. This shows
kprobe events on "tracing/dynamic_events" file.

User can also define new events via tracing/dynamic_events.

Link: http://lkml.kernel.org/r/154140855646.17322.6619219995865980392.stgit@devbox

Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 Documentation/trace/kprobetrace.rst |   3 +
 kernel/trace/Kconfig                |   1 +
 kernel/trace/trace_kprobe.c         | 319 +++++++++++++++-------------
 kernel/trace/trace_probe.c          |  27 +++
 kernel/trace/trace_probe.h          |   2 +
 5 files changed, 207 insertions(+), 145 deletions(-)

diff --git a/Documentation/trace/kprobetrace.rst b/Documentation/trace/kprobetrace.rst
index 47e765c2f2c3..235ce2ab131a 100644
--- a/Documentation/trace/kprobetrace.rst
+++ b/Documentation/trace/kprobetrace.rst
@@ -20,6 +20,9 @@ current_tracer. Instead of that, add probe points via
 /sys/kernel/debug/tracing/kprobe_events, and enable it via
 /sys/kernel/debug/tracing/events/kprobes/<EVENT>/enable.
 
+You can also use /sys/kernel/debug/tracing/dynamic_events instead of
+kprobe_events. That interface will provide unified access to other
+dynamic events too.
 
 Synopsis of kprobe_events
 -------------------------
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index bf2e8a5a91f1..c0f6b0105609 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -461,6 +461,7 @@ config KPROBE_EVENTS
 	bool "Enable kprobes-based dynamic events"
 	select TRACING
 	select PROBE_EVENTS
+	select DYNAMIC_EVENTS
 	default y
 	help
 	  This allows the user to add tracing events (similar to tracepoints)
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index d313bcc259dc..bdf8c2ad5152 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -12,6 +12,7 @@
 #include <linux/rculist.h>
 #include <linux/error-injection.h>
 
+#include "trace_dynevent.h"
 #include "trace_kprobe_selftest.h"
 #include "trace_probe.h"
 #include "trace_probe_tmpl.h"
@@ -19,17 +20,51 @@
 #define KPROBE_EVENT_SYSTEM "kprobes"
 #define KRETPROBE_MAXACTIVE_MAX 4096
 
+static int trace_kprobe_create(int argc, const char **argv);
+static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev);
+static int trace_kprobe_release(struct dyn_event *ev);
+static bool trace_kprobe_is_busy(struct dyn_event *ev);
+static bool trace_kprobe_match(const char *system, const char *event,
+			       struct dyn_event *ev);
+
+static struct dyn_event_operations trace_kprobe_ops = {
+	.create = trace_kprobe_create,
+	.show = trace_kprobe_show,
+	.is_busy = trace_kprobe_is_busy,
+	.free = trace_kprobe_release,
+	.match = trace_kprobe_match,
+};
+
 /**
  * Kprobe event core functions
  */
 struct trace_kprobe {
-	struct list_head	list;
+	struct dyn_event	devent;
 	struct kretprobe	rp;	/* Use rp.kp for kprobe use */
 	unsigned long __percpu *nhit;
 	const char		*symbol;	/* symbol name */
 	struct trace_probe	tp;
 };
 
+static bool is_trace_kprobe(struct dyn_event *ev)
+{
+	return ev->ops == &trace_kprobe_ops;
+}
+
+static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev)
+{
+	return container_of(ev, struct trace_kprobe, devent);
+}
+
+/**
+ * for_each_trace_kprobe - iterate over the trace_kprobe list
+ * @pos:	the struct trace_kprobe * for each entry
+ * @dpos:	the struct dyn_event * to use as a loop cursor
+ */
+#define for_each_trace_kprobe(pos, dpos)	\
+	for_each_dyn_event(dpos)		\
+		if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos)))
+
 #define SIZEOF_TRACE_KPROBE(n)				\
 	(offsetof(struct trace_kprobe, tp.args) +	\
 	(sizeof(struct probe_arg) * (n)))
@@ -81,6 +116,22 @@ static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
 	return ret;
 }
 
+static bool trace_kprobe_is_busy(struct dyn_event *ev)
+{
+	struct trace_kprobe *tk = to_trace_kprobe(ev);
+
+	return trace_probe_is_enabled(&tk->tp);
+}
+
+static bool trace_kprobe_match(const char *system, const char *event,
+			       struct dyn_event *ev)
+{
+	struct trace_kprobe *tk = to_trace_kprobe(ev);
+
+	return strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
+	    (!system || strcmp(tk->tp.call.class->system, system) == 0);
+}
+
 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
 {
 	unsigned long nhit = 0;
@@ -128,9 +179,6 @@ bool trace_kprobe_error_injectable(struct trace_event_call *call)
 static int register_kprobe_event(struct trace_kprobe *tk);
 static int unregister_kprobe_event(struct trace_kprobe *tk);
 
-static DEFINE_MUTEX(probe_lock);
-static LIST_HEAD(probe_list);
-
 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
 				struct pt_regs *regs);
@@ -192,7 +240,7 @@ static struct trace_kprobe *alloc_trace_kprobe(const char *group,
 	if (!tk->tp.class.system)
 		goto error;
 
-	INIT_LIST_HEAD(&tk->list);
+	dyn_event_init(&tk->devent, &trace_kprobe_ops);
 	INIT_LIST_HEAD(&tk->tp.files);
 	return tk;
 error:
@@ -207,6 +255,9 @@ static void free_trace_kprobe(struct trace_kprobe *tk)
 {
 	int i;
 
+	if (!tk)
+		return;
+
 	for (i = 0; i < tk->tp.nr_args; i++)
 		traceprobe_free_probe_arg(&tk->tp.args[i]);
 
@@ -220,9 +271,10 @@ static void free_trace_kprobe(struct trace_kprobe *tk)
 static struct trace_kprobe *find_trace_kprobe(const char *event,
 					      const char *group)
 {
+	struct dyn_event *pos;
 	struct trace_kprobe *tk;
 
-	list_for_each_entry(tk, &probe_list, list)
+	for_each_trace_kprobe(tk, pos)
 		if (strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
 		    strcmp(tk->tp.call.class->system, group) == 0)
 			return tk;
@@ -321,7 +373,7 @@ disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
 	 * created with perf_event_open. We don't need to wait for these
 	 * trace_kprobes
 	 */
-	if (list_empty(&tk->list))
+	if (list_empty(&tk->devent.list))
 		wait = 0;
  out:
 	if (wait) {
@@ -419,7 +471,7 @@ static void __unregister_trace_kprobe(struct trace_kprobe *tk)
 	}
 }
 
-/* Unregister a trace_probe and probe_event: call with locking probe_lock */
+/* Unregister a trace_probe and probe_event */
 static int unregister_trace_kprobe(struct trace_kprobe *tk)
 {
 	/* Enabled event can not be unregistered */
@@ -431,7 +483,7 @@ static int unregister_trace_kprobe(struct trace_kprobe *tk)
 		return -EBUSY;
 
 	__unregister_trace_kprobe(tk);
-	list_del(&tk->list);
+	dyn_event_remove(&tk->devent);
 
 	return 0;
 }
@@ -442,7 +494,7 @@ static int register_trace_kprobe(struct trace_kprobe *tk)
 	struct trace_kprobe *old_tk;
 	int ret;
 
-	mutex_lock(&probe_lock);
+	mutex_lock(&event_mutex);
 
 	/* Delete old (same name) event if exist */
 	old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call),
@@ -471,10 +523,10 @@ static int register_trace_kprobe(struct trace_kprobe *tk)
 	if (ret < 0)
 		unregister_kprobe_event(tk);
 	else
-		list_add_tail(&tk->list, &probe_list);
+		dyn_event_add(&tk->devent);
 
 end:
-	mutex_unlock(&probe_lock);
+	mutex_unlock(&event_mutex);
 	return ret;
 }
 
@@ -483,6 +535,7 @@ static int trace_kprobe_module_callback(struct notifier_block *nb,
 				       unsigned long val, void *data)
 {
 	struct module *mod = data;
+	struct dyn_event *pos;
 	struct trace_kprobe *tk;
 	int ret;
 
@@ -490,8 +543,8 @@ static int trace_kprobe_module_callback(struct notifier_block *nb,
 		return NOTIFY_DONE;
 
 	/* Update probes on coming module */
-	mutex_lock(&probe_lock);
-	list_for_each_entry(tk, &probe_list, list) {
+	mutex_lock(&event_mutex);
+	for_each_trace_kprobe(tk, pos) {
 		if (trace_kprobe_within_module(tk, mod)) {
 			/* Don't need to check busy - this should have gone. */
 			__unregister_trace_kprobe(tk);
@@ -502,7 +555,7 @@ static int trace_kprobe_module_callback(struct notifier_block *nb,
 					mod->name, ret);
 		}
 	}
-	mutex_unlock(&probe_lock);
+	mutex_unlock(&event_mutex);
 
 	return NOTIFY_DONE;
 }
@@ -520,7 +573,7 @@ static inline void sanitize_event_name(char *name)
 			*name = '_';
 }
 
-static int create_trace_kprobe(int argc, char **argv)
+static int trace_kprobe_create(int argc, const char *argv[])
 {
 	/*
 	 * Argument syntax:
@@ -544,9 +597,10 @@ static int create_trace_kprobe(int argc, char **argv)
 	 *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 	 */
 	struct trace_kprobe *tk;
-	int i, ret = 0;
-	bool is_return = false, is_delete = false;
-	char *symbol = NULL, *event = NULL, *group = NULL;
+	int i, len, ret = 0;
+	bool is_return = false;
+	char *symbol = NULL, *tmp = NULL;
+	const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
 	int maxactive = 0;
 	long offset = 0;
 	void *addr = NULL;
@@ -554,26 +608,26 @@ static int create_trace_kprobe(int argc, char **argv)
 	unsigned int flags = TPARG_FL_KERNEL;
 
 	/* argc must be >= 1 */
-	if (argv[0][0] == 'p')
-		is_return = false;
-	else if (argv[0][0] == 'r') {
+	if (argv[0][0] == 'r') {
 		is_return = true;
 		flags |= TPARG_FL_RETURN;
-	} else if (argv[0][0] == '-')
-		is_delete = true;
-	else {
-		pr_info("Probe definition must be started with 'p', 'r' or"
-			" '-'.\n");
-		return -EINVAL;
-	}
+	} else if (argv[0][0] != 'p' || argc < 2)
+		return -ECANCELED;
 
 	event = strchr(&argv[0][1], ':');
-	if (event) {
-		event[0] = '\0';
+	if (event)
 		event++;
-	}
+
 	if (is_return && isdigit(argv[0][1])) {
-		ret = kstrtouint(&argv[0][1], 0, &maxactive);
+		if (event)
+			len = event - &argv[0][1] - 1;
+		else
+			len = strlen(&argv[0][1]);
+		if (len > MAX_EVENT_NAME_LEN - 1)
+			return -E2BIG;
+		memcpy(buf, &argv[0][1], len);
+		buf[len] = '\0';
+		ret = kstrtouint(buf, 0, &maxactive);
 		if (ret) {
 			pr_info("Failed to parse maxactive.\n");
 			return ret;
@@ -588,74 +642,37 @@ static int create_trace_kprobe(int argc, char **argv)
 		}
 	}
 
-	if (event) {
-		char *slash;
-
-		slash = strchr(event, '/');
-		if (slash) {
-			group = event;
-			event = slash + 1;
-			slash[0] = '\0';
-			if (strlen(group) == 0) {
-				pr_info("Group name is not specified\n");
-				return -EINVAL;
-			}
-		}
-		if (strlen(event) == 0) {
-			pr_info("Event name is not specified\n");
-			return -EINVAL;
-		}
-	}
-	if (!group)
-		group = KPROBE_EVENT_SYSTEM;
-
-	if (is_delete) {
-		if (!event) {
-			pr_info("Delete command needs an event name.\n");
-			return -EINVAL;
-		}
-		mutex_lock(&probe_lock);
-		tk = find_trace_kprobe(event, group);
-		if (!tk) {
-			mutex_unlock(&probe_lock);
-			pr_info("Event %s/%s doesn't exist.\n", group, event);
-			return -ENOENT;
-		}
-		/* delete an event */
-		ret = unregister_trace_kprobe(tk);
-		if (ret == 0)
-			free_trace_kprobe(tk);
-		mutex_unlock(&probe_lock);
-		return ret;
-	}
-
-	if (argc < 2) {
-		pr_info("Probe point is not specified.\n");
-		return -EINVAL;
-	}
-
 	/* try to parse an address. if that fails, try to read the
 	 * input as a symbol. */
 	if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
+		/* Check whether uprobe event specified */
+		if (strchr(argv[1], '/') && strchr(argv[1], ':'))
+			return -ECANCELED;
 		/* a symbol specified */
-		symbol = argv[1];
+		symbol = kstrdup(argv[1], GFP_KERNEL);
+		if (!symbol)
+			return -ENOMEM;
 		/* TODO: support .init module functions */
 		ret = traceprobe_split_symbol_offset(symbol, &offset);
 		if (ret || offset < 0 || offset > UINT_MAX) {
 			pr_info("Failed to parse either an address or a symbol.\n");
-			return ret;
+			goto out;
 		}
 		if (kprobe_on_func_entry(NULL, symbol, offset))
 			flags |= TPARG_FL_FENTRY;
 		if (offset && is_return && !(flags & TPARG_FL_FENTRY)) {
 			pr_info("Given offset is not valid for return probe.\n");
-			return -EINVAL;
+			ret = -EINVAL;
+			goto out;
 		}
 	}
 	argc -= 2; argv += 2;
 
-	/* setup a probe */
-	if (!event) {
+	if (event) {
+		ret = traceprobe_parse_event_name(&event, &group, buf);
+		if (ret)
+			goto out;
+	} else {
 		/* Make a new event name */
 		if (symbol)
 			snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
@@ -666,17 +683,27 @@ static int create_trace_kprobe(int argc, char **argv)
 		sanitize_event_name(buf);
 		event = buf;
 	}
+
+	/* setup a probe */
 	tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
 			       argc, is_return);
 	if (IS_ERR(tk)) {
 		pr_info("Failed to allocate trace_probe.(%d)\n",
 			(int)PTR_ERR(tk));
-		return PTR_ERR(tk);
+		ret = PTR_ERR(tk);
+		goto out;
 	}
 
 	/* parse arguments */
 	for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
-		ret = traceprobe_parse_probe_arg(&tk->tp, i, argv[i], flags);
+		tmp = kstrdup(argv[i], GFP_KERNEL);
+		if (!tmp) {
+			ret = -ENOMEM;
+			goto error;
+		}
+
+		ret = traceprobe_parse_probe_arg(&tk->tp, i, tmp, flags);
+		kfree(tmp);
 		if (ret)
 			goto error;
 	}
@@ -684,60 +711,39 @@ static int create_trace_kprobe(int argc, char **argv)
 	ret = register_trace_kprobe(tk);
 	if (ret)
 		goto error;
-	return 0;
+out:
+	kfree(symbol);
+	return ret;
 
 error:
 	free_trace_kprobe(tk);
-	return ret;
+	goto out;
 }
 
-static int release_all_trace_kprobes(void)
+static int create_or_delete_trace_kprobe(int argc, char **argv)
 {
-	struct trace_kprobe *tk;
-	int ret = 0;
-
-	mutex_lock(&probe_lock);
-	/* Ensure no probe is in use. */
-	list_for_each_entry(tk, &probe_list, list)
-		if (trace_probe_is_enabled(&tk->tp)) {
-			ret = -EBUSY;
-			goto end;
-		}
-	/* TODO: Use batch unregistration */
-	while (!list_empty(&probe_list)) {
-		tk = list_entry(probe_list.next, struct trace_kprobe, list);
-		ret = unregister_trace_kprobe(tk);
-		if (ret)
-			goto end;
-		free_trace_kprobe(tk);
-	}
-
-end:
-	mutex_unlock(&probe_lock);
+	int ret;
 
-	return ret;
-}
+	if (argv[0][0] == '-')
+		return dyn_event_release(argc, argv, &trace_kprobe_ops);
 
-/* Probes listing interfaces */
-static void *probes_seq_start(struct seq_file *m, loff_t *pos)
-{
-	mutex_lock(&probe_lock);
-	return seq_list_start(&probe_list, *pos);
+	ret = trace_kprobe_create(argc, (const char **)argv);
+	return ret == -ECANCELED ? -EINVAL : ret;
 }
 
-static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
+static int trace_kprobe_release(struct dyn_event *ev)
 {
-	return seq_list_next(v, &probe_list, pos);
-}
+	struct trace_kprobe *tk = to_trace_kprobe(ev);
+	int ret = unregister_trace_kprobe(tk);
 
-static void probes_seq_stop(struct seq_file *m, void *v)
-{
-	mutex_unlock(&probe_lock);
+	if (!ret)
+		free_trace_kprobe(tk);
+	return ret;
 }
 
-static int probes_seq_show(struct seq_file *m, void *v)
+static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
 {
-	struct trace_kprobe *tk = v;
+	struct trace_kprobe *tk = to_trace_kprobe(ev);
 	int i;
 
 	seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
@@ -759,10 +765,20 @@ static int probes_seq_show(struct seq_file *m, void *v)
 	return 0;
 }
 
+static int probes_seq_show(struct seq_file *m, void *v)
+{
+	struct dyn_event *ev = v;
+
+	if (!is_trace_kprobe(ev))
+		return 0;
+
+	return trace_kprobe_show(m, ev);
+}
+
 static const struct seq_operations probes_seq_op = {
-	.start  = probes_seq_start,
-	.next   = probes_seq_next,
-	.stop   = probes_seq_stop,
+	.start  = dyn_event_seq_start,
+	.next   = dyn_event_seq_next,
+	.stop   = dyn_event_seq_stop,
 	.show   = probes_seq_show
 };
 
@@ -771,7 +787,7 @@ static int probes_open(struct inode *inode, struct file *file)
 	int ret;
 
 	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
-		ret = release_all_trace_kprobes();
+		ret = dyn_events_release_all(&trace_kprobe_ops);
 		if (ret < 0)
 			return ret;
 	}
@@ -783,7 +799,7 @@ static ssize_t probes_write(struct file *file, const char __user *buffer,
 			    size_t count, loff_t *ppos)
 {
 	return trace_parse_run_command(file, buffer, count, ppos,
-				       create_trace_kprobe);
+				       create_or_delete_trace_kprobe);
 }
 
 static const struct file_operations kprobe_events_ops = {
@@ -798,8 +814,13 @@ static const struct file_operations kprobe_events_ops = {
 /* Probes profiling interfaces */
 static int probes_profile_seq_show(struct seq_file *m, void *v)
 {
-	struct trace_kprobe *tk = v;
+	struct dyn_event *ev = v;
+	struct trace_kprobe *tk;
 
+	if (!is_trace_kprobe(ev))
+		return 0;
+
+	tk = to_trace_kprobe(ev);
 	seq_printf(m, "  %-44s %15lu %15lu\n",
 		   trace_event_name(&tk->tp.call),
 		   trace_kprobe_nhit(tk),
@@ -809,9 +830,9 @@ static int probes_profile_seq_show(struct seq_file *m, void *v)
 }
 
 static const struct seq_operations profile_seq_op = {
-	.start  = probes_seq_start,
-	.next   = probes_seq_next,
-	.stop   = probes_seq_stop,
+	.start  = dyn_event_seq_start,
+	.next   = dyn_event_seq_next,
+	.stop   = dyn_event_seq_stop,
 	.show   = probes_profile_seq_show
 };
 
@@ -1332,7 +1353,7 @@ static int register_kprobe_event(struct trace_kprobe *tk)
 		kfree(call->print_fmt);
 		return -ENODEV;
 	}
-	ret = trace_add_event_call(call);
+	ret = trace_add_event_call_nolock(call);
 	if (ret) {
 		pr_info("Failed to register kprobe event: %s\n",
 			trace_event_name(call));
@@ -1347,7 +1368,7 @@ static int unregister_kprobe_event(struct trace_kprobe *tk)
 	int ret;
 
 	/* tp->event is unregistered in trace_remove_event_call() */
-	ret = trace_remove_event_call(&tk->tp.call);
+	ret = trace_remove_event_call_nolock(&tk->tp.call);
 	if (!ret)
 		kfree(tk->tp.call.print_fmt);
 	return ret;
@@ -1364,7 +1385,7 @@ create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
 	char *event;
 
 	/*
-	 * local trace_kprobes are not added to probe_list, so they are never
+	 * local trace_kprobes are not added to dyn_event, so they are never
 	 * searched in find_trace_kprobe(). Therefore, there is no concern of
 	 * duplicated name here.
 	 */
@@ -1422,6 +1443,11 @@ static __init int init_kprobe_trace(void)
 {
 	struct dentry *d_tracer;
 	struct dentry *entry;
+	int ret;
+
+	ret = dyn_event_register(&trace_kprobe_ops);
+	if (ret)
+		return ret;
 
 	if (register_module_notifier(&trace_kprobe_module_nb))
 		return -EINVAL;
@@ -1479,9 +1505,8 @@ static __init int kprobe_trace_self_tests_init(void)
 
 	pr_info("Testing kprobe tracing: ");
 
-	ret = trace_run_command("p:testprobe kprobe_trace_selftest_target "
-				"$stack $stack0 +0($stack)",
-				create_trace_kprobe);
+	ret = trace_run_command("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)",
+				create_or_delete_trace_kprobe);
 	if (WARN_ON_ONCE(ret)) {
 		pr_warn("error on probing function entry.\n");
 		warn++;
@@ -1501,8 +1526,8 @@ static __init int kprobe_trace_self_tests_init(void)
 		}
 	}
 
-	ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target "
-				"$retval", create_trace_kprobe);
+	ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target $retval",
+				create_or_delete_trace_kprobe);
 	if (WARN_ON_ONCE(ret)) {
 		pr_warn("error on probing function return.\n");
 		warn++;
@@ -1572,20 +1597,24 @@ static __init int kprobe_trace_self_tests_init(void)
 			disable_trace_kprobe(tk, file);
 	}
 
-	ret = trace_run_command("-:testprobe", create_trace_kprobe);
+	ret = trace_run_command("-:testprobe", create_or_delete_trace_kprobe);
 	if (WARN_ON_ONCE(ret)) {
 		pr_warn("error on deleting a probe.\n");
 		warn++;
 	}
 
-	ret = trace_run_command("-:testprobe2", create_trace_kprobe);
+	ret = trace_run_command("-:testprobe2", create_or_delete_trace_kprobe);
 	if (WARN_ON_ONCE(ret)) {
 		pr_warn("error on deleting a probe.\n");
 		warn++;
 	}
 
 end:
-	release_all_trace_kprobes();
+	ret = dyn_events_release_all(&trace_kprobe_ops);
+	if (WARN_ON_ONCE(ret)) {
+		pr_warn("error on cleaning up probes.\n");
+		warn++;
+	}
 	/*
 	 * Wait for the optimizer work to finish. Otherwise it might fiddle
 	 * with probes in already freed __init text.
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 449150c6a87f..ff86417c0149 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -154,6 +154,33 @@ int traceprobe_split_symbol_offset(char *symbol, long *offset)
 	return 0;
 }
 
+/* @buf must has MAX_EVENT_NAME_LEN size */
+int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
+				char *buf)
+{
+	const char *slash, *event = *pevent;
+
+	slash = strchr(event, '/');
+	if (slash) {
+		if (slash == event) {
+			pr_info("Group name is not specified\n");
+			return -EINVAL;
+		}
+		if (slash - event + 1 > MAX_EVENT_NAME_LEN) {
+			pr_info("Group name is too long\n");
+			return -E2BIG;
+		}
+		strlcpy(buf, event, slash - event + 1);
+		*pgroup = buf;
+		*pevent = slash + 1;
+	}
+	if (strlen(event) == 0) {
+		pr_info("Event name is not specified\n");
+		return -EINVAL;
+	}
+	return 0;
+}
+
 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
 
 static int parse_probe_vars(char *arg, const struct fetch_type *t,
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index feeec261b356..8a63f8bc01bc 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -279,6 +279,8 @@ extern int traceprobe_update_arg(struct probe_arg *arg);
 extern void traceprobe_free_probe_arg(struct probe_arg *arg);
 
 extern int traceprobe_split_symbol_offset(char *symbol, long *offset);
+extern int traceprobe_parse_event_name(const char **pevent,
+				       const char **pgroup, char *buf);
 
 extern int traceprobe_set_print_fmt(struct trace_probe *tp, bool is_return);
 
-- 
2.19.1

[for-next][PATCH 25/30] tracing/uprobes: Use dyn_event framework for uprobe events

[Steven Rostedt]

From: Masami Hiramatsu <mhiramat@kernel.org>

Use dyn_event framework for uprobe events. This shows
uprobe events on "dynamic_events" file.
User can also define new uprobe events via dynamic_events.

Link: http://lkml.kernel.org/r/154140858481.17322.9091293846515154065.stgit@devbox

Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 Documentation/trace/uprobetracer.rst |   4 +
 kernel/trace/Kconfig                 |   1 +
 kernel/trace/trace_uprobe.c          | 278 ++++++++++++++-------------
 3 files changed, 153 insertions(+), 130 deletions(-)

diff --git a/Documentation/trace/uprobetracer.rst b/Documentation/trace/uprobetracer.rst
index d0822811527a..4c3bfde2ba47 100644
--- a/Documentation/trace/uprobetracer.rst
+++ b/Documentation/trace/uprobetracer.rst
@@ -18,6 +18,10 @@ current_tracer. Instead of that, add probe points via
 However unlike kprobe-event tracer, the uprobe event interface expects the
 user to calculate the offset of the probepoint in the object.
 
+You can also use /sys/kernel/debug/tracing/dynamic_events instead of
+uprobe_events. That interface will provide unified access to other
+dynamic events too.
+
 Synopsis of uprobe_tracer
 -------------------------
 ::
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index c0f6b0105609..2cab3c5dfe2c 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -501,6 +501,7 @@ config UPROBE_EVENTS
 	depends on PERF_EVENTS
 	select UPROBES
 	select PROBE_EVENTS
+	select DYNAMIC_EVENTS
 	select TRACING
 	default y
 	help
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 6eaaa2150685..4a7b21c891f3 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -7,6 +7,7 @@
  */
 #define pr_fmt(fmt)	"trace_kprobe: " fmt
 
+#include <linux/ctype.h>
 #include <linux/module.h>
 #include <linux/uaccess.h>
 #include <linux/uprobes.h>
@@ -14,6 +15,7 @@
 #include <linux/string.h>
 #include <linux/rculist.h>
 
+#include "trace_dynevent.h"
 #include "trace_probe.h"
 #include "trace_probe_tmpl.h"
 
@@ -37,11 +39,26 @@ struct trace_uprobe_filter {
 	struct list_head	perf_events;
 };
 
+static int trace_uprobe_create(int argc, const char **argv);
+static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev);
+static int trace_uprobe_release(struct dyn_event *ev);
+static bool trace_uprobe_is_busy(struct dyn_event *ev);
+static bool trace_uprobe_match(const char *system, const char *event,
+			       struct dyn_event *ev);
+
+static struct dyn_event_operations trace_uprobe_ops = {
+	.create = trace_uprobe_create,
+	.show = trace_uprobe_show,
+	.is_busy = trace_uprobe_is_busy,
+	.free = trace_uprobe_release,
+	.match = trace_uprobe_match,
+};
+
 /*
  * uprobe event core functions
  */
 struct trace_uprobe {
-	struct list_head		list;
+	struct dyn_event		devent;
 	struct trace_uprobe_filter	filter;
 	struct uprobe_consumer		consumer;
 	struct path			path;
@@ -53,6 +70,25 @@ struct trace_uprobe {
 	struct trace_probe		tp;
 };
 
+static bool is_trace_uprobe(struct dyn_event *ev)
+{
+	return ev->ops == &trace_uprobe_ops;
+}
+
+static struct trace_uprobe *to_trace_uprobe(struct dyn_event *ev)
+{
+	return container_of(ev, struct trace_uprobe, devent);
+}
+
+/**
+ * for_each_trace_uprobe - iterate over the trace_uprobe list
+ * @pos:	the struct trace_uprobe * for each entry
+ * @dpos:	the struct dyn_event * to use as a loop cursor
+ */
+#define for_each_trace_uprobe(pos, dpos)	\
+	for_each_dyn_event(dpos)		\
+		if (is_trace_uprobe(dpos) && (pos = to_trace_uprobe(dpos)))
+
 #define SIZEOF_TRACE_UPROBE(n)				\
 	(offsetof(struct trace_uprobe, tp.args) +	\
 	(sizeof(struct probe_arg) * (n)))
@@ -60,9 +96,6 @@ struct trace_uprobe {
 static int register_uprobe_event(struct trace_uprobe *tu);
 static int unregister_uprobe_event(struct trace_uprobe *tu);
 
-static DEFINE_MUTEX(uprobe_lock);
-static LIST_HEAD(uprobe_list);
-
 struct uprobe_dispatch_data {
 	struct trace_uprobe	*tu;
 	unsigned long		bp_addr;
@@ -209,6 +242,22 @@ static inline bool is_ret_probe(struct trace_uprobe *tu)
 	return tu->consumer.ret_handler != NULL;
 }
 
+static bool trace_uprobe_is_busy(struct dyn_event *ev)
+{
+	struct trace_uprobe *tu = to_trace_uprobe(ev);
+
+	return trace_probe_is_enabled(&tu->tp);
+}
+
+static bool trace_uprobe_match(const char *system, const char *event,
+			       struct dyn_event *ev)
+{
+	struct trace_uprobe *tu = to_trace_uprobe(ev);
+
+	return strcmp(trace_event_name(&tu->tp.call), event) == 0 &&
+		(!system || strcmp(tu->tp.call.class->system, system) == 0);
+}
+
 /*
  * Allocate new trace_uprobe and initialize it (including uprobes).
  */
@@ -236,7 +285,7 @@ alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
 	if (!tu->tp.class.system)
 		goto error;
 
-	INIT_LIST_HEAD(&tu->list);
+	dyn_event_init(&tu->devent, &trace_uprobe_ops);
 	INIT_LIST_HEAD(&tu->tp.files);
 	tu->consumer.handler = uprobe_dispatcher;
 	if (is_ret)
@@ -255,6 +304,9 @@ static void free_trace_uprobe(struct trace_uprobe *tu)
 {
 	int i;
 
+	if (!tu)
+		return;
+
 	for (i = 0; i < tu->tp.nr_args; i++)
 		traceprobe_free_probe_arg(&tu->tp.args[i]);
 
@@ -267,9 +319,10 @@ static void free_trace_uprobe(struct trace_uprobe *tu)
 
 static struct trace_uprobe *find_probe_event(const char *event, const char *group)
 {
+	struct dyn_event *pos;
 	struct trace_uprobe *tu;
 
-	list_for_each_entry(tu, &uprobe_list, list)
+	for_each_trace_uprobe(tu, pos)
 		if (strcmp(trace_event_name(&tu->tp.call), event) == 0 &&
 		    strcmp(tu->tp.call.class->system, group) == 0)
 			return tu;
@@ -277,7 +330,7 @@ static struct trace_uprobe *find_probe_event(const char *event, const char *grou
 	return NULL;
 }
 
-/* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */
+/* Unregister a trace_uprobe and probe_event */
 static int unregister_trace_uprobe(struct trace_uprobe *tu)
 {
 	int ret;
@@ -286,7 +339,7 @@ static int unregister_trace_uprobe(struct trace_uprobe *tu)
 	if (ret)
 		return ret;
 
-	list_del(&tu->list);
+	dyn_event_remove(&tu->devent);
 	free_trace_uprobe(tu);
 	return 0;
 }
@@ -302,13 +355,14 @@ static int unregister_trace_uprobe(struct trace_uprobe *tu)
  */
 static struct trace_uprobe *find_old_trace_uprobe(struct trace_uprobe *new)
 {
+	struct dyn_event *pos;
 	struct trace_uprobe *tmp, *old = NULL;
 	struct inode *new_inode = d_real_inode(new->path.dentry);
 
 	old = find_probe_event(trace_event_name(&new->tp.call),
 				new->tp.call.class->system);
 
-	list_for_each_entry(tmp, &uprobe_list, list) {
+	for_each_trace_uprobe(tmp, pos) {
 		if ((old ? old != tmp : true) &&
 		    new_inode == d_real_inode(tmp->path.dentry) &&
 		    new->offset == tmp->offset &&
@@ -326,7 +380,7 @@ static int register_trace_uprobe(struct trace_uprobe *tu)
 	struct trace_uprobe *old_tu;
 	int ret;
 
-	mutex_lock(&uprobe_lock);
+	mutex_lock(&event_mutex);
 
 	/* register as an event */
 	old_tu = find_old_trace_uprobe(tu);
@@ -348,10 +402,10 @@ static int register_trace_uprobe(struct trace_uprobe *tu)
 		goto end;
 	}
 
-	list_add_tail(&tu->list, &uprobe_list);
+	dyn_event_add(&tu->devent);
 
 end:
-	mutex_unlock(&uprobe_lock);
+	mutex_unlock(&event_mutex);
 
 	return ret;
 }
@@ -362,91 +416,49 @@ static int register_trace_uprobe(struct trace_uprobe *tu)
  *
  *  - Remove uprobe: -:[GRP/]EVENT
  */
-static int create_trace_uprobe(int argc, char **argv)
+static int trace_uprobe_create(int argc, const char **argv)
 {
 	struct trace_uprobe *tu;
-	char *arg, *event, *group, *filename, *rctr, *rctr_end;
+	const char *event = NULL, *group = UPROBE_EVENT_SYSTEM;
+	char *arg, *filename, *rctr, *rctr_end, *tmp;
 	char buf[MAX_EVENT_NAME_LEN];
 	struct path path;
 	unsigned long offset, ref_ctr_offset;
-	bool is_delete, is_return;
+	bool is_return = false;
 	int i, ret;
 
 	ret = 0;
-	is_delete = false;
-	is_return = false;
-	event = NULL;
-	group = NULL;
 	ref_ctr_offset = 0;
 
 	/* argc must be >= 1 */
-	if (argv[0][0] == '-')
-		is_delete = true;
-	else if (argv[0][0] == 'r')
+	if (argv[0][0] == 'r')
 		is_return = true;
-	else if (argv[0][0] != 'p') {
-		pr_info("Probe definition must be started with 'p', 'r' or '-'.\n");
-		return -EINVAL;
-	}
+	else if (argv[0][0] != 'p' || argc < 2)
+		return -ECANCELED;
 
-	if (argv[0][1] == ':') {
+	if (argv[0][1] == ':')
 		event = &argv[0][2];
-		arg = strchr(event, '/');
 
-		if (arg) {
-			group = event;
-			event = arg + 1;
-			event[-1] = '\0';
+	if (!strchr(argv[1], '/'))
+		return -ECANCELED;
 
-			if (strlen(group) == 0) {
-				pr_info("Group name is not specified\n");
-				return -EINVAL;
-			}
-		}
-		if (strlen(event) == 0) {
-			pr_info("Event name is not specified\n");
-			return -EINVAL;
-		}
-	}
-	if (!group)
-		group = UPROBE_EVENT_SYSTEM;
-
-	if (is_delete) {
-		int ret;
-
-		if (!event) {
-			pr_info("Delete command needs an event name.\n");
-			return -EINVAL;
-		}
-		mutex_lock(&uprobe_lock);
-		tu = find_probe_event(event, group);
-
-		if (!tu) {
-			mutex_unlock(&uprobe_lock);
-			pr_info("Event %s/%s doesn't exist.\n", group, event);
-			return -ENOENT;
-		}
-		/* delete an event */
-		ret = unregister_trace_uprobe(tu);
-		mutex_unlock(&uprobe_lock);
-		return ret;
-	}
+	filename = kstrdup(argv[1], GFP_KERNEL);
+	if (!filename)
+		return -ENOMEM;
 
-	if (argc < 2) {
-		pr_info("Probe point is not specified.\n");
-		return -EINVAL;
-	}
 	/* Find the last occurrence, in case the path contains ':' too. */
-	arg = strrchr(argv[1], ':');
-	if (!arg)
-		return -EINVAL;
+	arg = strrchr(filename, ':');
+	if (!arg || !isdigit(arg[1])) {
+		kfree(filename);
+		return -ECANCELED;
+	}
 
 	*arg++ = '\0';
-	filename = argv[1];
 	ret = kern_path(filename, LOOKUP_FOLLOW, &path);
-	if (ret)
+	if (ret) {
+		kfree(filename);
 		return ret;
-
+	}
 	if (!d_is_reg(path.dentry)) {
 		ret = -EINVAL;
 		goto fail_address_parse;
@@ -480,7 +492,11 @@ static int create_trace_uprobe(int argc, char **argv)
 	argv += 2;
 
 	/* setup a probe */
-	if (!event) {
+	if (event) {
+		ret = traceprobe_parse_event_name(&event, &group, buf);
+		if (ret)
+			goto fail_address_parse;
+	} else {
 		char *tail;
 		char *ptr;
 
@@ -508,18 +524,19 @@ static int create_trace_uprobe(int argc, char **argv)
 	tu->offset = offset;
 	tu->ref_ctr_offset = ref_ctr_offset;
 	tu->path = path;
-	tu->filename = kstrdup(filename, GFP_KERNEL);
-
-	if (!tu->filename) {
-		pr_info("Failed to allocate filename.\n");
-		ret = -ENOMEM;
-		goto error;
-	}
+	tu->filename = filename;
 
 	/* parse arguments */
 	for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
-		ret = traceprobe_parse_probe_arg(&tu->tp, i, argv[i],
+		tmp = kstrdup(argv[i], GFP_KERNEL);
+		if (!tmp) {
+			ret = -ENOMEM;
+			goto error;
+		}
+
+		ret = traceprobe_parse_probe_arg(&tu->tp, i, tmp,
 					is_return ? TPARG_FL_RETURN : 0);
+		kfree(tmp);
 		if (ret)
 			goto error;
 	}
@@ -535,55 +552,35 @@ static int create_trace_uprobe(int argc, char **argv)
 
 fail_address_parse:
 	path_put(&path);
+	kfree(filename);
 
 	pr_info("Failed to parse address or file.\n");
 
 	return ret;
 }
 
-static int cleanup_all_probes(void)
+static int create_or_delete_trace_uprobe(int argc, char **argv)
 {
-	struct trace_uprobe *tu;
-	int ret = 0;
+	int ret;
 
-	mutex_lock(&uprobe_lock);
-	/* Ensure no probe is in use. */
-	list_for_each_entry(tu, &uprobe_list, list)
-		if (trace_probe_is_enabled(&tu->tp)) {
-			ret = -EBUSY;
-			goto end;
-		}
-	while (!list_empty(&uprobe_list)) {
-		tu = list_entry(uprobe_list.next, struct trace_uprobe, list);
-		ret = unregister_trace_uprobe(tu);
-		if (ret)
-			break;
-	}
-end:
-	mutex_unlock(&uprobe_lock);
-	return ret;
-}
+	if (argv[0][0] == '-')
+		return dyn_event_release(argc, argv, &trace_uprobe_ops);
 
-/* Probes listing interfaces */
-static void *probes_seq_start(struct seq_file *m, loff_t *pos)
-{
-	mutex_lock(&uprobe_lock);
-	return seq_list_start(&uprobe_list, *pos);
+	ret = trace_uprobe_create(argc, (const char **)argv);
+	return ret == -ECANCELED ? -EINVAL : ret;
 }
 
-static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
+static int trace_uprobe_release(struct dyn_event *ev)
 {
-	return seq_list_next(v, &uprobe_list, pos);
-}
+	struct trace_uprobe *tu = to_trace_uprobe(ev);
 
-static void probes_seq_stop(struct seq_file *m, void *v)
-{
-	mutex_unlock(&uprobe_lock);
+	return unregister_trace_uprobe(tu);
 }
 
-static int probes_seq_show(struct seq_file *m, void *v)
+/* Probes listing interfaces */
+static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev)
 {
-	struct trace_uprobe *tu = v;
+	struct trace_uprobe *tu = to_trace_uprobe(ev);
 	char c = is_ret_probe(tu) ? 'r' : 'p';
 	int i;
 
@@ -601,11 +598,21 @@ static int probes_seq_show(struct seq_file *m, void *v)
 	return 0;
 }
 
+static int probes_seq_show(struct seq_file *m, void *v)
+{
+	struct dyn_event *ev = v;
+
+	if (!is_trace_uprobe(ev))
+		return 0;
+
+	return trace_uprobe_show(m, ev);
+}
+
 static const struct seq_operations probes_seq_op = {
-	.start	= probes_seq_start,
-	.next	= probes_seq_next,
-	.stop	= probes_seq_stop,
-	.show	= probes_seq_show
+	.start  = dyn_event_seq_start,
+	.next   = dyn_event_seq_next,
+	.stop   = dyn_event_seq_stop,
+	.show   = probes_seq_show
 };
 
 static int probes_open(struct inode *inode, struct file *file)
@@ -613,7 +620,7 @@ static int probes_open(struct inode *inode, struct file *file)
 	int ret;
 
 	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
-		ret = cleanup_all_probes();
+		ret = dyn_events_release_all(&trace_uprobe_ops);
 		if (ret)
 			return ret;
 	}
@@ -624,7 +631,8 @@ static int probes_open(struct inode *inode, struct file *file)
 static ssize_t probes_write(struct file *file, const char __user *buffer,
 			    size_t count, loff_t *ppos)
 {
-	return trace_parse_run_command(file, buffer, count, ppos, create_trace_uprobe);
+	return trace_parse_run_command(file, buffer, count, ppos,
+					create_or_delete_trace_uprobe);
 }
 
 static const struct file_operations uprobe_events_ops = {
@@ -639,17 +647,22 @@ static const struct file_operations uprobe_events_ops = {
 /* Probes profiling interfaces */
 static int probes_profile_seq_show(struct seq_file *m, void *v)
 {
-	struct trace_uprobe *tu = v;
+	struct dyn_event *ev = v;
+	struct trace_uprobe *tu;
+
+	if (!is_trace_uprobe(ev))
+		return 0;
 
+	tu = to_trace_uprobe(ev);
 	seq_printf(m, "  %s %-44s %15lu\n", tu->filename,
 			trace_event_name(&tu->tp.call), tu->nhit);
 	return 0;
 }
 
 static const struct seq_operations profile_seq_op = {
-	.start	= probes_seq_start,
-	.next	= probes_seq_next,
-	.stop	= probes_seq_stop,
+	.start  = dyn_event_seq_start,
+	.next   = dyn_event_seq_next,
+	.stop   = dyn_event_seq_stop,
 	.show	= probes_profile_seq_show
 };
 
@@ -1307,7 +1320,7 @@ static int register_uprobe_event(struct trace_uprobe *tu)
 		return -ENODEV;
 	}
 
-	ret = trace_add_event_call(call);
+	ret = trace_add_event_call_nolock(call);
 
 	if (ret) {
 		pr_info("Failed to register uprobe event: %s\n",
@@ -1324,7 +1337,7 @@ static int unregister_uprobe_event(struct trace_uprobe *tu)
 	int ret;
 
 	/* tu->event is unregistered in trace_remove_event_call() */
-	ret = trace_remove_event_call(&tu->tp.call);
+	ret = trace_remove_event_call_nolock(&tu->tp.call);
 	if (ret)
 		return ret;
 	kfree(tu->tp.call.print_fmt);
@@ -1351,7 +1364,7 @@ create_local_trace_uprobe(char *name, unsigned long offs,
 	}
 
 	/*
-	 * local trace_kprobes are not added to probe_list, so they are never
+	 * local trace_kprobes are not added to dyn_event, so they are never
 	 * searched in find_trace_kprobe(). Therefore, there is no concern of
 	 * duplicated name "DUMMY_EVENT" here.
 	 */
@@ -1399,6 +1412,11 @@ void destroy_local_trace_uprobe(struct trace_event_call *event_call)
 static __init int init_uprobe_trace(void)
 {
 	struct dentry *d_tracer;
+	int ret;
+
+	ret = dyn_event_register(&trace_uprobe_ops);
+	if (ret)
+		return ret;
 
 	d_tracer = tracing_init_dentry();
 	if (IS_ERR(d_tracer))
-- 
2.19.1

[for-next][PATCH 26/30] tracing: Use dyn_event framework for synthetic events

[Steven Rostedt]

From: Masami Hiramatsu <mhiramat@kernel.org>

Use dyn_event framework for synthetic events. This shows
synthetic events on "tracing/dynamic_events" file in addition
to tracing/synthetic_events interface.

User can also define new events via tracing/dynamic_events
with "s:" prefix. So, the new syntax is below;

  s:[synthetic/]EVENT_NAME TYPE ARG; [TYPE ARG;]...

To remove events via tracing/dynamic_events, you can use
"-:" prefix as same as other events.

Link: http://lkml.kernel.org/r/154140861301.17322.15454611233735614508.stgit@devbox

Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/Kconfig             |   1 +
 kernel/trace/trace.c             |   8 +
 kernel/trace/trace_events_hist.c | 265 +++++++++++++++++++------------
 3 files changed, 176 insertions(+), 98 deletions(-)

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 2cab3c5dfe2c..fa8b1fe824f3 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -635,6 +635,7 @@ config HIST_TRIGGERS
 	depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select TRACING_MAP
 	select TRACING
+	select DYNAMIC_EVENTS
 	default n
 	help
 	  Hist triggers allow one or more arbitrary trace event fields
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 7e0332f90ed4..911470ad9e94 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4620,6 +4620,9 @@ static const char readme_msg[] =
 	"\t  accepts: event-definitions (one definition per line)\n"
 	"\t   Format: p[:[<group>/]<event>] <place> [<args>]\n"
 	"\t           r[maxactive][:[<group>/]<event>] <place> [<args>]\n"
+#ifdef CONFIG_HIST_TRIGGERS
+	"\t           s:[synthetic/]<event> <field> [<field>]\n"
+#endif
 	"\t           -:[<group>/]<event>\n"
 #ifdef CONFIG_KPROBE_EVENTS
 	"\t    place: [<module>:]<symbol>[+<offset>]|<memaddr>\n"
@@ -4638,6 +4641,11 @@ static const char readme_msg[] =
 	"\t     type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string, symbol,\n"
 	"\t           b<bit-width>@<bit-offset>/<container-size>,\n"
 	"\t           <type>\\[<array-size>\\]\n"
+#ifdef CONFIG_HIST_TRIGGERS
+	"\t    field: <stype> <name>;\n"
+	"\t    stype: u8/u16/u32/u64, s8/s16/s32/s64, pid_t,\n"
+	"\t           [unsigned] char/int/long\n"
+#endif
 #endif
 	"  events/\t\t- Directory containing all trace event subsystems:\n"
 	"      enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 0feb7f460123..414aabd67d1f 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -15,6 +15,7 @@
 
 #include "tracing_map.h"
 #include "trace.h"
+#include "trace_dynevent.h"
 
 #define SYNTH_SYSTEM		"synthetic"
 #define SYNTH_FIELDS_MAX	16
@@ -292,6 +293,21 @@ struct hist_trigger_data {
 	unsigned int			n_max_var_str;
 };
 
+static int synth_event_create(int argc, const char **argv);
+static int synth_event_show(struct seq_file *m, struct dyn_event *ev);
+static int synth_event_release(struct dyn_event *ev);
+static bool synth_event_is_busy(struct dyn_event *ev);
+static bool synth_event_match(const char *system, const char *event,
+			      struct dyn_event *ev);
+
+static struct dyn_event_operations synth_event_ops = {
+	.create = synth_event_create,
+	.show = synth_event_show,
+	.is_busy = synth_event_is_busy,
+	.free = synth_event_release,
+	.match = synth_event_match,
+};
+
 struct synth_field {
 	char *type;
 	char *name;
@@ -301,7 +317,7 @@ struct synth_field {
 };
 
 struct synth_event {
-	struct list_head			list;
+	struct dyn_event			devent;
 	int					ref;
 	char					*name;
 	struct synth_field			**fields;
@@ -312,6 +328,32 @@ struct synth_event {
 	struct tracepoint			*tp;
 };
 
+static bool is_synth_event(struct dyn_event *ev)
+{
+	return ev->ops == &synth_event_ops;
+}
+
+static struct synth_event *to_synth_event(struct dyn_event *ev)
+{
+	return container_of(ev, struct synth_event, devent);
+}
+
+static bool synth_event_is_busy(struct dyn_event *ev)
+{
+	struct synth_event *event = to_synth_event(ev);
+
+	return event->ref != 0;
+}
+
+static bool synth_event_match(const char *system, const char *event,
+			      struct dyn_event *ev)
+{
+	struct synth_event *sev = to_synth_event(ev);
+
+	return strcmp(sev->name, event) == 0 &&
+		(!system || strcmp(system, SYNTH_SYSTEM) == 0);
+}
+
 struct action_data;
 
 typedef void (*action_fn_t) (struct hist_trigger_data *hist_data,
@@ -402,7 +444,6 @@ static bool have_hist_err(void)
 	return false;
 }
 
-static LIST_HEAD(synth_event_list);
 static DEFINE_MUTEX(synth_event_mutex);
 
 struct synth_trace_event {
@@ -738,14 +779,12 @@ static void free_synth_field(struct synth_field *field)
 	kfree(field);
 }
 
-static struct synth_field *parse_synth_field(int argc, char **argv,
+static struct synth_field *parse_synth_field(int argc, const char **argv,
 					     int *consumed)
 {
 	struct synth_field *field;
-	const char *prefix = NULL;
-	char *field_type = argv[0], *field_name;
+	const char *prefix = NULL, *field_type = argv[0], *field_name, *array;
 	int len, ret = 0;
-	char *array;
 
 	if (field_type[0] == ';')
 		field_type++;
@@ -762,20 +801,31 @@ static struct synth_field *parse_synth_field(int argc, char **argv,
 		*consumed = 2;
 	}
 
-	len = strlen(field_name);
-	if (field_name[len - 1] == ';')
-		field_name[len - 1] = '\0';
-
 	field = kzalloc(sizeof(*field), GFP_KERNEL);
 	if (!field)
 		return ERR_PTR(-ENOMEM);
 
-	len = strlen(field_type) + 1;
+	len = strlen(field_name);
 	array = strchr(field_name, '[');
+	if (array)
+		len -= strlen(array);
+	else if (field_name[len - 1] == ';')
+		len--;
+
+	field->name = kmemdup_nul(field_name, len, GFP_KERNEL);
+	if (!field->name) {
+		ret = -ENOMEM;
+		goto free;
+	}
+
+	if (field_type[0] == ';')
+		field_type++;
+	len = strlen(field_type) + 1;
 	if (array)
 		len += strlen(array);
 	if (prefix)
 		len += strlen(prefix);
+
 	field->type = kzalloc(len, GFP_KERNEL);
 	if (!field->type) {
 		ret = -ENOMEM;
@@ -786,7 +836,8 @@ static struct synth_field *parse_synth_field(int argc, char **argv,
 	strcat(field->type, field_type);
 	if (array) {
 		strcat(field->type, array);
-		*array = '\0';
+		if (field->type[len - 1] == ';')
+			field->type[len - 1] = '\0';
 	}
 
 	field->size = synth_field_size(field->type);
@@ -800,11 +851,6 @@ static struct synth_field *parse_synth_field(int argc, char **argv,
 
 	field->is_signed = synth_field_signed(field->type);
 
-	field->name = kstrdup(field_name, GFP_KERNEL);
-	if (!field->name) {
-		ret = -ENOMEM;
-		goto free;
-	}
  out:
 	return field;
  free:
@@ -868,9 +914,13 @@ static inline void trace_synth(struct synth_event *event, u64 *var_ref_vals,
 
 static struct synth_event *find_synth_event(const char *name)
 {
+	struct dyn_event *pos;
 	struct synth_event *event;
 
-	list_for_each_entry(event, &synth_event_list, list) {
+	for_each_dyn_event(pos) {
+		if (!is_synth_event(pos))
+			continue;
+		event = to_synth_event(pos);
 		if (strcmp(event->name, name) == 0)
 			return event;
 	}
@@ -921,7 +971,7 @@ static int register_synth_event(struct synth_event *event)
 
 	ret = set_synth_event_print_fmt(call);
 	if (ret < 0) {
-		trace_remove_event_call(call);
+		trace_remove_event_call_nolock(call);
 		goto err;
 	}
  out:
@@ -959,7 +1009,7 @@ static void free_synth_event(struct synth_event *event)
 	kfree(event);
 }
 
-static struct synth_event *alloc_synth_event(char *event_name, int n_fields,
+static struct synth_event *alloc_synth_event(const char *name, int n_fields,
 					     struct synth_field **fields)
 {
 	struct synth_event *event;
@@ -971,7 +1021,7 @@ static struct synth_event *alloc_synth_event(char *event_name, int n_fields,
 		goto out;
 	}
 
-	event->name = kstrdup(event_name, GFP_KERNEL);
+	event->name = kstrdup(name, GFP_KERNEL);
 	if (!event->name) {
 		kfree(event);
 		event = ERR_PTR(-ENOMEM);
@@ -985,6 +1035,8 @@ static struct synth_event *alloc_synth_event(char *event_name, int n_fields,
 		goto out;
 	}
 
+	dyn_event_init(&event->devent, &synth_event_ops);
+
 	for (i = 0; i < n_fields; i++)
 		event->fields[i] = fields[i];
 
@@ -1008,16 +1060,11 @@ struct hist_var_data {
 	struct hist_trigger_data *hist_data;
 };
 
-static int create_synth_event(int argc, char **argv)
+static int __create_synth_event(int argc, const char *name, const char **argv)
 {
 	struct synth_field *field, *fields[SYNTH_FIELDS_MAX];
 	struct synth_event *event = NULL;
-	bool delete_event = false;
 	int i, consumed = 0, n_fields = 0, ret = 0;
-	char *name;
-
-	mutex_lock(&event_mutex);
-	mutex_lock(&synth_event_mutex);
 
 	/*
 	 * Argument syntax:
@@ -1025,43 +1072,20 @@ static int create_synth_event(int argc, char **argv)
 	 *  - Remove synthetic event: !<event_name> field[;field] ...
 	 *      where 'field' = type field_name
 	 */
-	if (argc < 1) {
-		ret = -EINVAL;
-		goto out;
-	}
 
-	name = argv[0];
-	if (name[0] == '!') {
-		delete_event = true;
-		name++;
-	}
+	if (name[0] == '\0' || argc < 1)
+		return -EINVAL;
+
+	mutex_lock(&event_mutex);
+	mutex_lock(&synth_event_mutex);
 
 	event = find_synth_event(name);
 	if (event) {
-		if (delete_event) {
-			if (event->ref) {
-				ret = -EBUSY;
-				goto out;
-			}
-			ret = unregister_synth_event(event);
-			if (!ret) {
-				list_del(&event->list);
-				free_synth_event(event);
-			}
-		} else
-			ret = -EEXIST;
-		goto out;
-	} else if (delete_event) {
-		ret = -ENOENT;
+		ret = -EEXIST;
 		goto out;
 	}
 
-	if (argc < 2) {
-		ret = -EINVAL;
-		goto out;
-	}
-
-	for (i = 1; i < argc - 1; i++) {
+	for (i = 0; i < argc - 1; i++) {
 		if (strcmp(argv[i], ";") == 0)
 			continue;
 		if (n_fields == SYNTH_FIELDS_MAX) {
@@ -1091,7 +1115,7 @@ static int create_synth_event(int argc, char **argv)
 	}
 	ret = register_synth_event(event);
 	if (!ret)
-		list_add(&event->list, &synth_event_list);
+		dyn_event_add(&event->devent);
 	else
 		free_synth_event(event);
  out:
@@ -1106,57 +1130,77 @@ static int create_synth_event(int argc, char **argv)
 	goto out;
 }
 
-static int release_all_synth_events(void)
+static int create_or_delete_synth_event(int argc, char **argv)
 {
-	struct synth_event *event, *e;
-	int ret = 0;
-
-	mutex_lock(&event_mutex);
-	mutex_lock(&synth_event_mutex);
-
-	list_for_each_entry(event, &synth_event_list, list) {
-		if (event->ref) {
-			mutex_unlock(&synth_event_mutex);
-			return -EBUSY;
-		}
-	}
+	const char *name = argv[0];
+	struct synth_event *event = NULL;
+	int ret;
 
-	list_for_each_entry_safe(event, e, &synth_event_list, list) {
-		ret = unregister_synth_event(event);
-		if (!ret) {
-			list_del(&event->list);
-			free_synth_event(event);
+	/* trace_run_command() ensures argc != 0 */
+	if (name[0] == '!') {
+		mutex_lock(&event_mutex);
+		mutex_lock(&synth_event_mutex);
+		event = find_synth_event(name + 1);
+		if (event) {
+			if (event->ref)
+				ret = -EBUSY;
+			else {
+				ret = unregister_synth_event(event);
+				if (!ret) {
+					dyn_event_remove(&event->devent);
+					free_synth_event(event);
+				}
+			}
 		} else
-			break;
+			ret = -ENOENT;
+		mutex_unlock(&synth_event_mutex);
+		mutex_unlock(&event_mutex);
+		return ret;
 	}
-	mutex_unlock(&synth_event_mutex);
-	mutex_unlock(&event_mutex);
 
-	return ret;
+	ret = __create_synth_event(argc - 1, name, (const char **)argv + 1);
+	return ret == -ECANCELED ? -EINVAL : ret;
 }
 
-
-static void *synth_events_seq_start(struct seq_file *m, loff_t *pos)
+static int synth_event_create(int argc, const char **argv)
 {
-	mutex_lock(&synth_event_mutex);
+	const char *name = argv[0];
+	int len;
 
-	return seq_list_start(&synth_event_list, *pos);
-}
+	if (name[0] != 's' || name[1] != ':')
+		return -ECANCELED;
+	name += 2;
 
-static void *synth_events_seq_next(struct seq_file *m, void *v, loff_t *pos)
-{
-	return seq_list_next(v, &synth_event_list, pos);
+	/* This interface accepts group name prefix */
+	if (strchr(name, '/')) {
+		len = sizeof(SYNTH_SYSTEM "/") - 1;
+		if (strncmp(name, SYNTH_SYSTEM "/", len))
+			return -EINVAL;
+		name += len;
+	}
+	return __create_synth_event(argc - 1, name, argv + 1);
 }
 
-static void synth_events_seq_stop(struct seq_file *m, void *v)
+static int synth_event_release(struct dyn_event *ev)
 {
-	mutex_unlock(&synth_event_mutex);
+	struct synth_event *event = to_synth_event(ev);
+	int ret;
+
+	if (event->ref)
+		return -EBUSY;
+
+	ret = unregister_synth_event(event);
+	if (ret)
+		return ret;
+
+	dyn_event_remove(ev);
+	free_synth_event(event);
+	return 0;
 }
 
-static int synth_events_seq_show(struct seq_file *m, void *v)
+static int __synth_event_show(struct seq_file *m, struct synth_event *event)
 {
 	struct synth_field *field;
-	struct synth_event *event = v;
 	unsigned int i;
 
 	seq_printf(m, "%s\t", event->name);
@@ -1174,11 +1218,30 @@ static int synth_events_seq_show(struct seq_file *m, void *v)
 	return 0;
 }
 
+static int synth_event_show(struct seq_file *m, struct dyn_event *ev)
+{
+	struct synth_event *event = to_synth_event(ev);
+
+	seq_printf(m, "s:%s/", event->class.system);
+
+	return __synth_event_show(m, event);
+}
+
+static int synth_events_seq_show(struct seq_file *m, void *v)
+{
+	struct dyn_event *ev = v;
+
+	if (!is_synth_event(ev))
+		return 0;
+
+	return __synth_event_show(m, to_synth_event(ev));
+}
+
 static const struct seq_operations synth_events_seq_op = {
-	.start  = synth_events_seq_start,
-	.next   = synth_events_seq_next,
-	.stop   = synth_events_seq_stop,
-	.show   = synth_events_seq_show
+	.start	= dyn_event_seq_start,
+	.next	= dyn_event_seq_next,
+	.stop	= dyn_event_seq_stop,
+	.show	= synth_events_seq_show,
 };
 
 static int synth_events_open(struct inode *inode, struct file *file)
@@ -1186,7 +1249,7 @@ static int synth_events_open(struct inode *inode, struct file *file)
 	int ret;
 
 	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
-		ret = release_all_synth_events();
+		ret = dyn_events_release_all(&synth_event_ops);
 		if (ret < 0)
 			return ret;
 	}
@@ -1199,7 +1262,7 @@ static ssize_t synth_events_write(struct file *file,
 				  size_t count, loff_t *ppos)
 {
 	return trace_parse_run_command(file, buffer, count, ppos,
-				       create_synth_event);
+				       create_or_delete_synth_event);
 }
 
 static const struct file_operations synth_events_fops = {
@@ -5791,6 +5854,12 @@ static __init int trace_events_hist_init(void)
 	struct dentry *d_tracer;
 	int err = 0;
 
+	err = dyn_event_register(&synth_event_ops);
+	if (err) {
+		pr_warn("Could not register synth_event_ops\n");
+		return err;
+	}
+
 	d_tracer = tracing_init_dentry();
 	if (IS_ERR(d_tracer)) {
 		err = PTR_ERR(d_tracer);
-- 
2.19.1

[for-next][PATCH 27/30] tracing: Remove unneeded synth_event_mutex

[Steven Rostedt]

From: Masami Hiramatsu <mhiramat@kernel.org>

Rmove unneeded synth_event_mutex. This mutex protects the reference
count in synth_event, however, those operational points are already
protected by event_mutex.

1. In __create_synth_event() and create_or_delete_synth_event(),
 those synth_event_mutex clearly obtained right after event_mutex.

2. event_hist_trigger_func() is trigger_hist_cmd.func() which is
 called by trigger_process_regex(), which is a part of
 event_trigger_regex_write() and this function takes event_mutex.

3. hist_unreg_all() is trigger_hist_cmd.unreg_all() which is called
 by event_trigger_regex_open() and it takes event_mutex.

4. onmatch_destroy() and onmatch_create() have long call tree,
 but both are finally invoked from event_trigger_regex_write()
 and event_trace_del_tracer(), former takes event_mutex, and latter
 ensures called under event_mutex locked.

Finally, I ensured there is no resource conflict. For safety,
I added lockdep_assert_held(&event_mutex) for each function.

Link: http://lkml.kernel.org/r/154140864134.17322.4796059721306031894.stgit@devbox

Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_events_hist.c | 30 +++++++-----------------------
 1 file changed, 7 insertions(+), 23 deletions(-)

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 414aabd67d1f..21e4954375a1 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -444,8 +444,6 @@ static bool have_hist_err(void)
 	return false;
 }
 
-static DEFINE_MUTEX(synth_event_mutex);
-
 struct synth_trace_event {
 	struct trace_entry	ent;
 	u64			fields[];
@@ -1077,7 +1075,6 @@ static int __create_synth_event(int argc, const char *name, const char **argv)
 		return -EINVAL;
 
 	mutex_lock(&event_mutex);
-	mutex_lock(&synth_event_mutex);
 
 	event = find_synth_event(name);
 	if (event) {
@@ -1119,7 +1116,6 @@ static int __create_synth_event(int argc, const char *name, const char **argv)
 	else
 		free_synth_event(event);
  out:
-	mutex_unlock(&synth_event_mutex);
 	mutex_unlock(&event_mutex);
 
 	return ret;
@@ -1139,7 +1135,6 @@ static int create_or_delete_synth_event(int argc, char **argv)
 	/* trace_run_command() ensures argc != 0 */
 	if (name[0] == '!') {
 		mutex_lock(&event_mutex);
-		mutex_lock(&synth_event_mutex);
 		event = find_synth_event(name + 1);
 		if (event) {
 			if (event->ref)
@@ -1153,7 +1148,6 @@ static int create_or_delete_synth_event(int argc, char **argv)
 			}
 		} else
 			ret = -ENOENT;
-		mutex_unlock(&synth_event_mutex);
 		mutex_unlock(&event_mutex);
 		return ret;
 	}
@@ -3535,7 +3529,7 @@ static void onmatch_destroy(struct action_data *data)
 {
 	unsigned int i;
 
-	mutex_lock(&synth_event_mutex);
+	lockdep_assert_held(&event_mutex);
 
 	kfree(data->onmatch.match_event);
 	kfree(data->onmatch.match_event_system);
@@ -3548,8 +3542,6 @@ static void onmatch_destroy(struct action_data *data)
 		data->onmatch.synth_event->ref--;
 
 	kfree(data);
-
-	mutex_unlock(&synth_event_mutex);
 }
 
 static void destroy_field_var(struct field_var *field_var)
@@ -3700,15 +3692,14 @@ static int onmatch_create(struct hist_trigger_data *hist_data,
 	struct synth_event *event;
 	int ret = 0;
 
-	mutex_lock(&synth_event_mutex);
+	lockdep_assert_held(&event_mutex);
+
 	event = find_synth_event(data->onmatch.synth_event_name);
 	if (!event) {
 		hist_err("onmatch: Couldn't find synthetic event: ", data->onmatch.synth_event_name);
-		mutex_unlock(&synth_event_mutex);
 		return -EINVAL;
 	}
 	event->ref++;
-	mutex_unlock(&synth_event_mutex);
 
 	var_ref_idx = hist_data->n_var_refs;
 
@@ -3782,9 +3773,7 @@ static int onmatch_create(struct hist_trigger_data *hist_data,
  out:
 	return ret;
  err:
-	mutex_lock(&synth_event_mutex);
 	event->ref--;
-	mutex_unlock(&synth_event_mutex);
 
 	goto out;
 }
@@ -5492,6 +5481,8 @@ static void hist_unreg_all(struct trace_event_file *file)
 	struct synth_event *se;
 	const char *se_name;
 
+	lockdep_assert_held(&event_mutex);
+
 	if (hist_file_check_refs(file))
 		return;
 
@@ -5501,12 +5492,10 @@ static void hist_unreg_all(struct trace_event_file *file)
 			list_del_rcu(&test->list);
 			trace_event_trigger_enable_disable(file, 0);
 
-			mutex_lock(&synth_event_mutex);
 			se_name = trace_event_name(file->event_call);
 			se = find_synth_event(se_name);
 			if (se)
 				se->ref--;
-			mutex_unlock(&synth_event_mutex);
 
 			update_cond_flag(file);
 			if (hist_data->enable_timestamps)
@@ -5532,6 +5521,8 @@ static int event_hist_trigger_func(struct event_command *cmd_ops,
 	char *trigger, *p;
 	int ret = 0;
 
+	lockdep_assert_held(&event_mutex);
+
 	if (glob && strlen(glob)) {
 		last_cmd_set(param);
 		hist_err_clear();
@@ -5622,14 +5613,10 @@ static int event_hist_trigger_func(struct event_command *cmd_ops,
 		}
 
 		cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
-
-		mutex_lock(&synth_event_mutex);
 		se_name = trace_event_name(file->event_call);
 		se = find_synth_event(se_name);
 		if (se)
 			se->ref--;
-		mutex_unlock(&synth_event_mutex);
-
 		ret = 0;
 		goto out_free;
 	}
@@ -5665,13 +5652,10 @@ static int event_hist_trigger_func(struct event_command *cmd_ops,
 	if (ret)
 		goto out_unreg;
 
-	mutex_lock(&synth_event_mutex);
 	se_name = trace_event_name(file->event_call);
 	se = find_synth_event(se_name);
 	if (se)
 		se->ref++;
-	mutex_unlock(&synth_event_mutex);
-
 	/* Just return zero, not the number of registered triggers */
 	ret = 0;
  out:
-- 
2.19.1

[for-next][PATCH 28/30] tracing: Consolidate trace_add/remove_event_call back to the nolock functions

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

The trace_add/remove_event_call_nolock() functions were added to allow
the tace_add/remove_event_call() code be called when the event_mutex
lock was already taken. Now that all callers are done within the
event_mutex, there's no reason to have two different interfaces.

Remove the current wrapper trace_add/remove_event_call()s and rename the
_nolock versions back to the original names.

Link: http://lkml.kernel.org/r/154140866955.17322.2081425494660638846.stgit@devbox

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/linux/trace_events.h     |  2 --
 kernel/trace/trace_events.c      | 30 ++++--------------------------
 kernel/trace/trace_events_hist.c |  6 +++---
 kernel/trace/trace_kprobe.c      |  4 ++--
 kernel/trace/trace_uprobe.c      |  4 ++--
 5 files changed, 11 insertions(+), 35 deletions(-)

diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 3aa05593a53f..4130a5497d40 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -529,8 +529,6 @@ extern int trace_event_raw_init(struct trace_event_call *call);
 extern int trace_define_field(struct trace_event_call *call, const char *type,
 			      const char *name, int offset, int size,
 			      int is_signed, int filter_type);
-extern int trace_add_event_call_nolock(struct trace_event_call *call);
-extern int trace_remove_event_call_nolock(struct trace_event_call *call);
 extern int trace_add_event_call(struct trace_event_call *call);
 extern int trace_remove_event_call(struct trace_event_call *call);
 extern int trace_event_get_offsets(struct trace_event_call *call);
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index a3b157f689ee..bd0162c0467c 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2305,7 +2305,8 @@ __trace_early_add_new_event(struct trace_event_call *call,
 struct ftrace_module_file_ops;
 static void __add_event_to_tracers(struct trace_event_call *call);
 
-int trace_add_event_call_nolock(struct trace_event_call *call)
+/* Add an additional event_call dynamically */
+int trace_add_event_call(struct trace_event_call *call)
 {
 	int ret;
 	lockdep_assert_held(&event_mutex);
@@ -2320,17 +2321,6 @@ int trace_add_event_call_nolock(struct trace_event_call *call)
 	return ret;
 }
 
-/* Add an additional event_call dynamically */
-int trace_add_event_call(struct trace_event_call *call)
-{
-	int ret;
-
-	mutex_lock(&event_mutex);
-	ret = trace_add_event_call_nolock(call);
-	mutex_unlock(&event_mutex);
-	return ret;
-}
-
 /*
  * Must be called under locking of trace_types_lock, event_mutex and
  * trace_event_sem.
@@ -2376,8 +2366,8 @@ static int probe_remove_event_call(struct trace_event_call *call)
 	return 0;
 }
 
-/* no event_mutex version */
-int trace_remove_event_call_nolock(struct trace_event_call *call)
+/* Remove an event_call */
+int trace_remove_event_call(struct trace_event_call *call)
 {
 	int ret;
 
@@ -2392,18 +2382,6 @@ int trace_remove_event_call_nolock(struct trace_event_call *call)
 	return ret;
 }
 
-/* Remove an event_call */
-int trace_remove_event_call(struct trace_event_call *call)
-{
-	int ret;
-
-	mutex_lock(&event_mutex);
-	ret = trace_remove_event_call_nolock(call);
-	mutex_unlock(&event_mutex);
-
-	return ret;
-}
-
 #define for_each_event(event, start, end)			\
 	for (event = start;					\
 	     (unsigned long)event < (unsigned long)end;		\
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 21e4954375a1..82e72c48a5a9 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -960,7 +960,7 @@ static int register_synth_event(struct synth_event *event)
 	call->data = event;
 	call->tp = event->tp;
 
-	ret = trace_add_event_call_nolock(call);
+	ret = trace_add_event_call(call);
 	if (ret) {
 		pr_warn("Failed to register synthetic event: %s\n",
 			trace_event_name(call));
@@ -969,7 +969,7 @@ static int register_synth_event(struct synth_event *event)
 
 	ret = set_synth_event_print_fmt(call);
 	if (ret < 0) {
-		trace_remove_event_call_nolock(call);
+		trace_remove_event_call(call);
 		goto err;
 	}
  out:
@@ -984,7 +984,7 @@ static int unregister_synth_event(struct synth_event *event)
 	struct trace_event_call *call = &event->call;
 	int ret;
 
-	ret = trace_remove_event_call_nolock(call);
+	ret = trace_remove_event_call(call);
 
 	return ret;
 }
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index bdf8c2ad5152..0e0f7b8024fb 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1353,7 +1353,7 @@ static int register_kprobe_event(struct trace_kprobe *tk)
 		kfree(call->print_fmt);
 		return -ENODEV;
 	}
-	ret = trace_add_event_call_nolock(call);
+	ret = trace_add_event_call(call);
 	if (ret) {
 		pr_info("Failed to register kprobe event: %s\n",
 			trace_event_name(call));
@@ -1368,7 +1368,7 @@ static int unregister_kprobe_event(struct trace_kprobe *tk)
 	int ret;
 
 	/* tp->event is unregistered in trace_remove_event_call() */
-	ret = trace_remove_event_call_nolock(&tk->tp.call);
+	ret = trace_remove_event_call(&tk->tp.call);
 	if (!ret)
 		kfree(tk->tp.call.print_fmt);
 	return ret;
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 4a7b21c891f3..e335576b9411 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -1320,7 +1320,7 @@ static int register_uprobe_event(struct trace_uprobe *tu)
 		return -ENODEV;
 	}
 
-	ret = trace_add_event_call_nolock(call);
+	ret = trace_add_event_call(call);
 
 	if (ret) {
 		pr_info("Failed to register uprobe event: %s\n",
@@ -1337,7 +1337,7 @@ static int unregister_uprobe_event(struct trace_uprobe *tu)
 	int ret;
 
 	/* tu->event is unregistered in trace_remove_event_call() */
-	ret = trace_remove_event_call_nolock(&tu->tp.call);
+	ret = trace_remove_event_call(&tu->tp.call);
 	if (ret)
 		return ret;
 	kfree(tu->tp.call.print_fmt);
-- 
2.19.1

[for-next][PATCH 29/30] tracing: Add generic event-name based remove event method

[Steven Rostedt]

From: Masami Hiramatsu <mhiramat@kernel.org>

Add a generic method to remove event from dynamic event
list. This is same as other system under ftrace. You
just need to pass the event name with '!', e.g.

  # echo p:new_grp/new_event _do_fork > dynamic_events

This creates an event, and

  # echo '!p:new_grp/new_event _do_fork' > dynamic_events

Or,

  # echo '!p:new_grp/new_event' > dynamic_events

will remove new_grp/new_event event.

Note that this doesn't check the event prefix (e.g. "p:")
strictly, because the "group/event" name must be unique.

Link: http://lkml.kernel.org/r/154140869774.17322.8887303560398645347.stgit@devbox

Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_dynevent.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/trace_dynevent.c b/kernel/trace/trace_dynevent.c
index f17a887abb66..dd1f43588d70 100644
--- a/kernel/trace/trace_dynevent.c
+++ b/kernel/trace/trace_dynevent.c
@@ -37,10 +37,17 @@ int dyn_event_release(int argc, char **argv, struct dyn_event_operations *type)
 	char *system = NULL, *event, *p;
 	int ret = -ENOENT;
 
-	if (argv[0][1] != ':')
-		return -EINVAL;
+	if (argv[0][0] == '-') {
+		if (argv[0][1] != ':')
+			return -EINVAL;
+		event = &argv[0][2];
+	} else {
+		event = strchr(argv[0], ':');
+		if (!event)
+			return -EINVAL;
+		event++;
+	}
 
-	event = &argv[0][2];
 	p = strchr(event, '/');
 	if (p) {
 		system = event;
@@ -69,7 +76,7 @@ static int create_dyn_event(int argc, char **argv)
 	struct dyn_event_operations *ops;
 	int ret;
 
-	if (argv[0][0] == '-')
+	if (argv[0][0] == '-' || argv[0][0] == '!')
 		return dyn_event_release(argc, argv, NULL);
 
 	mutex_lock(&dyn_event_ops_mutex);
-- 
2.19.1

[for-next][PATCH 30/30] selftests/ftrace: Add testcases for dynamic event

[Steven Rostedt]

From: Masami Hiramatsu <mhiramat@kernel.org>

Add common testcases for dynamic_events interface.
 - Add/remove kprobe events via dynamic_events
 - Add/remove synthetic events via dynamic_events
 - Selective clear events (clear events other interfaces)
 - Genelic clear events ("!LINE" syntax)

Link: http://lkml.kernel.org/r/154140872590.17322.10394440849261743052.stgit@devbox

Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 .../test.d/dynevent/add_remove_kprobe.tc      | 30 +++++++++++
 .../test.d/dynevent/add_remove_synth.tc       | 27 ++++++++++
 .../test.d/dynevent/clear_select_events.tc    | 50 +++++++++++++++++++
 .../test.d/dynevent/generic_clear_event.tc    | 49 ++++++++++++++++++
 4 files changed, 156 insertions(+)
 create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/add_remove_kprobe.tc
 create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/add_remove_synth.tc
 create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/clear_select_events.tc
 create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/generic_clear_event.tc

diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_kprobe.tc b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_kprobe.tc
new file mode 100644
index 000000000000..c6d8387dbbb8
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_kprobe.tc
@@ -0,0 +1,30 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Generic dynamic event - add/remove kprobe events
+
+[ -f dynamic_events ] || exit_unsupported
+
+grep -q "place: \[<module>:\]<symbol>" README || exit_unsupported
+grep -q "place (kretprobe): \[<module>:\]<symbol>" README || exit_unsupported
+
+echo 0 > events/enable
+echo > dynamic_events
+
+PLACE=_do_fork
+
+echo "p:myevent1 $PLACE" >> dynamic_events
+echo "r:myevent2 $PLACE" >> dynamic_events
+
+grep -q myevent1 dynamic_events
+grep -q myevent2 dynamic_events
+test -d events/kprobes/myevent1
+test -d events/kprobes/myevent2
+
+echo "-:myevent2" >> dynamic_events
+
+grep -q myevent1 dynamic_events
+! grep -q myevent2 dynamic_events
+
+echo > dynamic_events
+
+clear_trace
diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_synth.tc b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_synth.tc
new file mode 100644
index 000000000000..62b77b5941d0
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_synth.tc
@@ -0,0 +1,27 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Generic dynamic event - add/remove synthetic events
+
+[ -f dynamic_events ] || exit_unsupported
+
+grep -q "s:\[synthetic/\]" README || exit_unsupported
+
+echo 0 > events/enable
+echo > dynamic_events
+
+echo "s:latency1 u64 lat; pid_t pid;" >> dynamic_events
+echo "s:latency2 u64 lat; pid_t pid;" >> dynamic_events
+
+grep -q latency1 dynamic_events
+grep -q latency2 dynamic_events
+test -d events/synthetic/latency1
+test -d events/synthetic/latency2
+
+echo "-:synthetic/latency2" >> dynamic_events
+
+grep -q latency1 dynamic_events
+! grep -q latency2 dynamic_events
+
+echo > dynamic_events
+
+clear_trace
diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/clear_select_events.tc b/tools/testing/selftests/ftrace/test.d/dynevent/clear_select_events.tc
new file mode 100644
index 000000000000..e0842109cb57
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/dynevent/clear_select_events.tc
@@ -0,0 +1,50 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Generic dynamic event - selective clear (compatibility)
+
+[ -f dynamic_events ] || exit_unsupported
+
+grep -q "place: \[<module>:\]<symbol>" README || exit_unsupported
+grep -q "place (kretprobe): \[<module>:\]<symbol>" README || exit_unsupported
+
+grep -q "s:\[synthetic/\]" README || exit_unsupported
+
+[ -f synthetic_events ] || exit_unsupported
+[ -f kprobe_events ] || exit_unsupported
+
+echo 0 > events/enable
+echo > dynamic_events
+
+PLACE=_do_fork
+
+setup_events() {
+echo "p:myevent1 $PLACE" >> dynamic_events
+echo "s:latency1 u64 lat; pid_t pid;" >> dynamic_events
+echo "r:myevent2 $PLACE" >> dynamic_events
+echo "s:latency2 u64 lat; pid_t pid;" >> dynamic_events
+
+grep -q myevent1 dynamic_events
+grep -q myevent2 dynamic_events
+grep -q latency1 dynamic_events
+grep -q latency2 dynamic_events
+}
+
+setup_events
+echo > synthetic_events
+
+grep -q myevent1 dynamic_events
+grep -q myevent2 dynamic_events
+! grep -q latency1 dynamic_events
+! grep -q latency2 dynamic_events
+
+echo > dynamic_events
+
+setup_events
+echo > kprobe_events
+
+! grep -q myevent1 dynamic_events
+! grep -q myevent2 dynamic_events
+grep -q latency1 dynamic_events
+grep -q latency2 dynamic_events
+
+echo > dynamic_events
diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/generic_clear_event.tc b/tools/testing/selftests/ftrace/test.d/dynevent/generic_clear_event.tc
new file mode 100644
index 000000000000..901922e97878
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/dynevent/generic_clear_event.tc
@@ -0,0 +1,49 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Generic dynamic event - generic clear event
+
+[ -f dynamic_events ] || exit_unsupported
+
+grep -q "place: \[<module>:\]<symbol>" README || exit_unsupported
+grep -q "place (kretprobe): \[<module>:\]<symbol>" README || exit_unsupported
+
+grep -q "s:\[synthetic/\]" README || exit_unsupported
+
+echo 0 > events/enable
+echo > dynamic_events
+
+PLACE=_do_fork
+
+setup_events() {
+echo "p:myevent1 $PLACE" >> dynamic_events
+echo "s:latency1 u64 lat; pid_t pid;" >> dynamic_events
+echo "r:myevent2 $PLACE" >> dynamic_events
+echo "s:latency2 u64 lat; pid_t pid;" >> dynamic_events
+
+grep -q myevent1 dynamic_events
+grep -q myevent2 dynamic_events
+grep -q latency1 dynamic_events
+grep -q latency2 dynamic_events
+}
+
+setup_events
+
+echo "!p:myevent1 $PLACE" >> dynamic_events
+! grep -q myevent1 dynamic_events
+grep -q myevent2 dynamic_events
+grep -q latency1 dynamic_events
+grep -q latency2 dynamic_events
+
+echo "!s:latency1 u64 lat; pid_t pid;" >> dynamic_events
+grep -q myevent2 dynamic_events
+! grep -q latency1 dynamic_events
+grep -q latency2 dynamic_events
+
+echo "!r:myevent2 $PLACE" >> dynamic_events
+! grep -q myevent2 dynamic_events
+grep -q latency2 dynamic_events
+
+echo "!s:latency2 u64 lat; pid_t pid;" >> dynamic_events
+! grep -q latency2 dynamic_events
+
+echo > dynamic_events
-- 
2.19.1

Re: [for-next][PATCH 05/30] arm64: function_graph: Remove use of FTRACE_NOTRACE_DEPTH

[Steven Rostedt]

On Wed, 05 Dec 2018 18:47:54 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:

> From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> 
> Functions in the set_graph_notrace no longer subtract FTRACE_NOTRACE_DEPTH
> from curr_ret_stack, as that is now implemented via the trace_recursion
> flags. Access to curr_ret_stack no longer needs to worry about checking for
> this. curr_ret_stack is still initialized to -1, when there's not a shadow
> stack allocated.
> 
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will.deacon@arm.com>

I haven't pushed this to Linux next yet. I tested the entire tree as
well as crossed compiled it against arm64.

Can you give me an ack for this patch?

Thanks!

-- Steve

> Cc: linux-arm-kernel@lists.infradead.org
> Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> ---
>  arch/arm64/kernel/stacktrace.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
> index 4989f7ea1e59..7723dadf25be 100644
> --- a/arch/arm64/kernel/stacktrace.c
> +++ b/arch/arm64/kernel/stacktrace.c
> @@ -61,9 +61,6 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
>  			(frame->pc == (unsigned long)return_to_handler)) {
>  		if (WARN_ON_ONCE(frame->graph == -1))
>  			return -EINVAL;
> -		if (frame->graph < -1)
> -			frame->graph += FTRACE_NOTRACE_DEPTH;
> -
>  		/*
>  		 * This is a case where function graph tracer has
>  		 * modified a return address (LR) in a stack frame

Re: [for-next][PATCH 05/30] arm64: function_graph: Remove use of FTRACE_NOTRACE_DEPTH

[Will Deacon]

On Wed, Dec 05, 2018 at 06:47:54PM -0500, Steven Rostedt wrote:
> From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> 
> Functions in the set_graph_notrace no longer subtract FTRACE_NOTRACE_DEPTH
> from curr_ret_stack, as that is now implemented via the trace_recursion
> flags. Access to curr_ret_stack no longer needs to worry about checking for
> this. curr_ret_stack is still initialized to -1, when there's not a shadow
> stack allocated.
> 
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: linux-arm-kernel@lists.infradead.org
> Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> ---
>  arch/arm64/kernel/stacktrace.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
> index 4989f7ea1e59..7723dadf25be 100644
> --- a/arch/arm64/kernel/stacktrace.c
> +++ b/arch/arm64/kernel/stacktrace.c
> @@ -61,9 +61,6 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
>  			(frame->pc == (unsigned long)return_to_handler)) {
>  		if (WARN_ON_ONCE(frame->graph == -1))
>  			return -EINVAL;
> -		if (frame->graph < -1)
> -			frame->graph += FTRACE_NOTRACE_DEPTH;
> -

Acked-by: Will Deacon <will.deacon@arm.com>

Will

Re: [for-next][PATCH 05/30] arm64: function_graph: Remove use of FTRACE_NOTRACE_DEPTH

[Steven Rostedt]

On Thu, 6 Dec 2018 15:49:32 +0000
Will Deacon <will.deacon@arm.com> wrote:

> On Wed, Dec 05, 2018 at 06:47:54PM -0500, Steven Rostedt wrote:
> > From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> > 
> > Functions in the set_graph_notrace no longer subtract FTRACE_NOTRACE_DEPTH
> > from curr_ret_stack, as that is now implemented via the trace_recursion
> > flags. Access to curr_ret_stack no longer needs to worry about checking for
> > this. curr_ret_stack is still initialized to -1, when there's not a shadow
> > stack allocated.
> > 
> > Cc: Catalin Marinas <catalin.marinas@arm.com>
> > Cc: Will Deacon <will.deacon@arm.com>
> > Cc: linux-arm-kernel@lists.infradead.org
> > Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
> > Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> > ---
> >  arch/arm64/kernel/stacktrace.c | 3 ---
> >  1 file changed, 3 deletions(-)
> > 
> > diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
> > index 4989f7ea1e59..7723dadf25be 100644
> > --- a/arch/arm64/kernel/stacktrace.c
> > +++ b/arch/arm64/kernel/stacktrace.c
> > @@ -61,9 +61,6 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
> >  			(frame->pc == (unsigned long)return_to_handler)) {
> >  		if (WARN_ON_ONCE(frame->graph == -1))
> >  			return -EINVAL;
> > -		if (frame->graph < -1)
> > -			frame->graph += FTRACE_NOTRACE_DEPTH;
> > -  
> 
> Acked-by: Will Deacon <will.deacon@arm.com>
> 

Thanks Will!

-- Steve