[for-next][PATCH 00/34] tracing: My official queue finally passed testing and ready for linux-next

[for-next][PATCH 00/34] tracing: My official queue finally passed testing and ready for linux-next

[Steven Rostedt]

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

Head SHA1: f8a79d5c7ef47c62d97a30e16064caf2ef91f648


Colin Ian King (1):
      ftrace: Remove unused pointer ftrace_swapper_pid

Erica Bugden (1):
      ftrace: Add missing check for existing hwlat thread

Francis Deslauriers (1):
      selftest/ftrace: Move kprobe selftest function to separate compile unit

Gustavo A. R. Silva (1):
      ftrace: Use true and false for boolean values in ops_references_rec()

Joel Fernandes (Google) (9):
      srcu: Add notrace variant of srcu_dereference
      tracing/irqsoff: Split reset into separate functions
      lib: Add module for testing preemptoff/irqsoff latency tracers
      kselftests: Add tests for the preemptoff and irqsoff tracers
      lockdep: Use this_cpu_ptr instead of get_cpu_var stats
      tracepoint: Make rcuidle tracepoint callers use SRCU
      tracing: Centralize preemptirq tracepoints and unify their usage
      trace: Use rcu_dereference_raw for hooks from trace-event subsystem
      tracing: irqsoff: Account for additional preempt_disable

Masami Hiramatsu (5):
      tracing: Remove orphaned function using_ftrace_ops_list_func().
      tracing: Remove orphaned function ftrace_nr_registered_ops()
      tracing: kprobes: Prohibit probing on notrace function
      selftests/ftrace: Fix kprobe string testcase to not probe notrace function
      tracing/kprobes: Fix within_notrace_func() to check only notrace functions

Paul McKenney (1):
      srcu: Add notrace variants of srcu_read_{lock,unlock}

Steven Rostedt (VMware) (13):
      tracing: Make unregister_trigger() static
      tracing/kprobes: Simplify the logic of enable_trace_kprobe()
      tracing: Do not call start/stop() functions when tracing_on does not change
      tracing: Do a WARN_ON() if start_thread() in hwlat is called when thread exists
      tracing: Make tracer_tracing_is_on() return bool
      ring-buffer: Make ring_buffer_record_is_on() return bool
      ring-buffer: Make ring_buffer_record_is_set_on() return bool
      tracing: Partial revert of "tracing: Centralize preemptirq tracepoints and unify their usage"
      tracing/irqsoff: Handle preempt_count for different configs
      tracing: More reverting of "tracing: Centralize preemptirq tracepoints and unify their usage"
      tracing: Fix synchronizing to event changes with tracepoint_synchronize_unregister()
      uprobes: Use synchronize_rcu() not synchronize_sched()
      tracepoints: Free early tracepoints after RCU is initialized

Zubin Mithra (1):
      tracefs: Annotate tracefs_ops with __ro_after_init

kbuild test robot (1):
      tracing: preemptirq_delay_run() can be static

----
 fs/tracefs/inode.c                                 |   5 +-
 include/linux/ftrace.h                             |  17 +-
 include/linux/irqflags.h                           |  15 +-
 include/linux/lockdep.h                            |   6 +-
 include/linux/preempt.h                            |   2 +-
 include/linux/ring_buffer.h                        |   4 +-
 include/linux/srcu.h                               |  22 ++
 include/linux/tracepoint.h                         |  40 ++-
 include/trace/events/preemptirq.h                  |  23 +-
 init/main.c                                        |   3 +-
 kernel/locking/lockdep.c                           |  35 +--
 kernel/sched/core.c                                |   2 +-
 kernel/trace/Kconfig                               |  57 ++++-
 kernel/trace/Makefile                              |   8 +-
 kernel/trace/ftrace.c                              |  41 +---
 kernel/trace/preemptirq_delay_test.c               |  72 ++++++
 kernel/trace/ring_buffer.c                         |   4 +-
 kernel/trace/trace.c                               |   6 +-
 kernel/trace/trace.h                               |  21 +-
 kernel/trace/trace_events.c                        |  12 +-
 kernel/trace/trace_events_filter.c                 |  15 +-
 kernel/trace/trace_events_hist.c                   |   2 +-
 kernel/trace/trace_events_trigger.c                |  12 +-
 kernel/trace/trace_hwlat.c                         |   3 +
 kernel/trace/trace_irqsoff.c                       | 269 +++++++--------------
 kernel/trace/trace_kprobe.c                        | 103 +++++---
 kernel/trace/trace_kprobe_selftest.c               |  10 +
 kernel/trace/trace_kprobe_selftest.h               |   7 +
 kernel/trace/trace_preemptirq.c                    |  89 +++++++
 kernel/trace/trace_uprobe.c                        |   2 +-
 kernel/tracepoint.c                                |  48 +++-
 tools/testing/selftests/ftrace/config              |   3 +
 .../ftrace/test.d/kprobe/kprobe_args_string.tc     |  30 +--
 .../selftests/ftrace/test.d/kprobe/probepoint.tc   |   2 +-
 .../ftrace/test.d/preemptirq/irqsoff_tracer.tc     |  73 ++++++
 35 files changed, 670 insertions(+), 393 deletions(-)
 create mode 100644 kernel/trace/preemptirq_delay_test.c
 create mode 100644 kernel/trace/trace_kprobe_selftest.c
 create mode 100644 kernel/trace/trace_kprobe_selftest.h
 create mode 100644 kernel/trace/trace_preemptirq.c
 create mode 100644 tools/testing/selftests/ftrace/test.d/preemptirq/irqsoff_tracer.tc

[for-next][PATCH 01/34] srcu: Add notrace variants of srcu_read_{lock,unlock}

[Steven Rostedt]

From: Paul McKenney <paulmck@linux.vnet.ibm.com>

This is needed for a future tracepoint patch that uses srcu, and to make
sure it doesn't call into lockdep.

tracepoint code already calls notrace variants for rcu_read_lock_sched
so this patch does the same for srcu which will be used in a later
patch. Keeps it consistent with rcu-sched.

[Joel: Added commit message]
Link: http://lkml.kernel.org/r/20180628182149.226164-2-joel@joelfernandes.org

Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Paul McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/linux/srcu.h | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/include/linux/srcu.h b/include/linux/srcu.h
index 91494d7e8e41..3e72a291c401 100644
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h
@@ -195,6 +195,16 @@ static inline int srcu_read_lock(struct srcu_struct *sp) __acquires(sp)
 	return retval;
 }
 
+/* Used by tracing, cannot be traced and cannot invoke lockdep. */
+static inline notrace int
+srcu_read_lock_notrace(struct srcu_struct *sp) __acquires(sp)
+{
+	int retval;
+
+	retval = __srcu_read_lock(sp);
+	return retval;
+}
+
 /**
  * srcu_read_unlock - unregister a old reader from an SRCU-protected structure.
  * @sp: srcu_struct in which to unregister the old reader.
@@ -209,6 +219,13 @@ static inline void srcu_read_unlock(struct srcu_struct *sp, int idx)
 	__srcu_read_unlock(sp, idx);
 }
 
+/* Used by tracing, cannot be traced and cannot call lockdep. */
+static inline notrace void
+srcu_read_unlock_notrace(struct srcu_struct *sp, int idx) __releases(sp)
+{
+	__srcu_read_unlock(sp, idx);
+}
+
 /**
  * smp_mb__after_srcu_read_unlock - ensure full ordering after srcu_read_unlock
  *
-- 
2.18.0

[for-next][PATCH 02/34] srcu: Add notrace variant of srcu_dereference

[Steven Rostedt]

From: "Joel Fernandes (Google)" <joel@joelfernandes.org>

In the last patch in this series, we are making lockdep register hooks
onto the irq_{disable,enable} tracepoints. These tracepoints use the
_rcuidle tracepoint variant. In this series we switch the _rcuidle
tracepoint callers to use SRCU instead of sched-RCU. Inorder to
dereference the pointer to the probe functions, we could call
srcu_dereference, however this API will call back into lockdep to check
if the lock is held *before* the lockdep probe hooks have a chance to
run and annotate the IRQ enabled/disabled state.

For this reason we need a notrace variant of srcu_dereference since
otherwise we get lockdep splats. This patch adds the needed
srcu_dereference_notrace variant.

Link: http://lkml.kernel.org/r/20180628182149.226164-3-joel@joelfernandes.org

Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/linux/srcu.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/linux/srcu.h b/include/linux/srcu.h
index 3e72a291c401..67135d4a8a30 100644
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h
@@ -169,6 +169,11 @@ static inline int srcu_read_lock_held(const struct srcu_struct *sp)
  */
 #define srcu_dereference(p, sp) srcu_dereference_check((p), (sp), 0)
 
+/**
+ * srcu_dereference_notrace - no tracing and no lockdep calls from here
+ */
+#define srcu_dereference_notrace(p, sp) srcu_dereference_check((p), (sp), 1)
+
 /**
  * srcu_read_lock - register a new reader for an SRCU-protected structure.
  * @sp: srcu_struct in which to register the new reader.
-- 
2.18.0

[for-next][PATCH 03/34] tracing/irqsoff: Split reset into separate functions

[Steven Rostedt]

From: "Joel Fernandes (Google)" <joel@joelfernandes.org>

Split reset functions into seperate functions in preparation
of future patches that need to do tracer specific reset.

Link: http://lkml.kernel.org/r/20180628182149.226164-4-joel@joelfernandes.org

Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_irqsoff.c | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 03ecb4465ee4..f8daa754cce2 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -634,7 +634,7 @@ static int __irqsoff_tracer_init(struct trace_array *tr)
 	return 0;
 }
 
-static void irqsoff_tracer_reset(struct trace_array *tr)
+static void __irqsoff_tracer_reset(struct trace_array *tr)
 {
 	int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
 	int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
@@ -665,6 +665,12 @@ static int irqsoff_tracer_init(struct trace_array *tr)
 
 	return __irqsoff_tracer_init(tr);
 }
+
+static void irqsoff_tracer_reset(struct trace_array *tr)
+{
+	__irqsoff_tracer_reset(tr);
+}
+
 static struct tracer irqsoff_tracer __read_mostly =
 {
 	.name		= "irqsoff",
@@ -697,11 +703,16 @@ static int preemptoff_tracer_init(struct trace_array *tr)
 	return __irqsoff_tracer_init(tr);
 }
 
+static void preemptoff_tracer_reset(struct trace_array *tr)
+{
+	__irqsoff_tracer_reset(tr);
+}
+
 static struct tracer preemptoff_tracer __read_mostly =
 {
 	.name		= "preemptoff",
 	.init		= preemptoff_tracer_init,
-	.reset		= irqsoff_tracer_reset,
+	.reset		= preemptoff_tracer_reset,
 	.start		= irqsoff_tracer_start,
 	.stop		= irqsoff_tracer_stop,
 	.print_max	= true,
@@ -731,11 +742,16 @@ static int preemptirqsoff_tracer_init(struct trace_array *tr)
 	return __irqsoff_tracer_init(tr);
 }
 
+static void preemptirqsoff_tracer_reset(struct trace_array *tr)
+{
+	__irqsoff_tracer_reset(tr);
+}
+
 static struct tracer preemptirqsoff_tracer __read_mostly =
 {
 	.name		= "preemptirqsoff",
 	.init		= preemptirqsoff_tracer_init,
-	.reset		= irqsoff_tracer_reset,
+	.reset		= preemptirqsoff_tracer_reset,
 	.start		= irqsoff_tracer_start,
 	.stop		= irqsoff_tracer_stop,
 	.print_max	= true,
-- 
2.18.0

[for-next][PATCH 04/34] lib: Add module for testing preemptoff/irqsoff latency tracers

[Steven Rostedt]

From: "Joel Fernandes (Google)" <joel@joelfernandes.org>

Here we introduce a test module for introducing a long preempt or irq
disable delay in the kernel which the preemptoff or irqsoff tracers can
detect. This module is to be used only for test purposes and is default
disabled.

Following is the expected output (only briefly shown) that can be parsed
to verify that the tracers are working correctly. We will use this from
the kselftests in future patches.

For the preemptoff tracer:

echo preemptoff > /d/tracing/current_tracer
sleep 1
insmod ./preemptirq_delay_test.ko test_mode=preempt delay=500000
sleep 1
bash-4.3# cat /d/tracing/trace
preempt -1066    2...2    0us@: preemptirq_delay_run <-preemptirq_delay_run
preempt -1066    2...2 500002us : preemptirq_delay_run <-preemptirq_delay_run
preempt -1066    2...2 500004us : tracer_preempt_on <-preemptirq_delay_run
preempt -1066    2...2 500012us : <stack trace>
 => kthread
 => ret_from_fork

For the irqsoff tracer:

echo irqsoff > /d/tracing/current_tracer
sleep 1
insmod ./preemptirq_delay_test.ko test_mode=irq delay=500000
sleep 1
bash-4.3# cat /d/tracing/trace
irq dis -1069    1d..1    0us@: preemptirq_delay_run
irq dis -1069    1d..1 500001us : preemptirq_delay_run
irq dis -1069    1d..1 500002us : tracer_hardirqs_on <-preemptirq_delay_run
irq dis -1069    1d..1 500005us : <stack trace>
 => ret_from_fork

Link: http://lkml.kernel.org/r/20180712213611.GA8743@joelaf.mtv.corp.google.com

Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Julia Cartwright <julia@ni.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Glexiner <tglx@linutronix.de>
Cc: Todd Kjos <tkjos@google.com>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
[ Erick is a co-developer of this commit ]
Signed-off-by: Erick Reyes <erickreyes@google.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/Kconfig                 | 15 ++++++
 kernel/trace/Makefile                |  1 +
 kernel/trace/preemptirq_delay_test.c | 72 ++++++++++++++++++++++++++++
 3 files changed, 88 insertions(+)
 create mode 100644 kernel/trace/preemptirq_delay_test.c

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index dcc0166d1997..e15fadbe5dfb 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -687,6 +687,21 @@ config RING_BUFFER_STARTUP_TEST
 
 	 If unsure, say N
 
+config PREEMPTIRQ_DELAY_TEST
+	tristate "Preempt / IRQ disable delay thread to test latency tracers"
+	depends on m
+	help
+	  Select this option to build a test module that can help test latency
+	  tracers by executing a preempt or irq disable section with a user
+	  configurable delay. The module busy waits for the duration of the
+	  critical section.
+
+	  For example, the following invocation forces a one-time irq-disabled
+	  critical section for 500us:
+	  modprobe preemptirq_delay_test test_mode=irq delay=500000
+
+	  If unsure, say N
+
 config TRACE_EVAL_MAP_FILE
        bool "Show eval mappings for trace events"
        depends on TRACING
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index e2538c7638d4..31c6b524c260 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -33,6 +33,7 @@ obj-$(CONFIG_TRACING) += trace_seq.o
 obj-$(CONFIG_TRACING) += trace_stat.o
 obj-$(CONFIG_TRACING) += trace_printk.o
 obj-$(CONFIG_TRACING_MAP) += tracing_map.o
+obj-$(CONFIG_PREEMPTIRQ_DELAY_TEST) += preemptirq_delay_test.o
 obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
 obj-$(CONFIG_FUNCTION_TRACER) += trace_functions.o
 obj-$(CONFIG_PREEMPTIRQ_EVENTS) += trace_irqsoff.o
diff --git a/kernel/trace/preemptirq_delay_test.c b/kernel/trace/preemptirq_delay_test.c
new file mode 100644
index 000000000000..c97a026c0720
--- /dev/null
+++ b/kernel/trace/preemptirq_delay_test.c
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Preempt / IRQ disable delay thread to test latency tracers
+ *
+ * Copyright (C) 2018 Joel Fernandes (Google) <joel@joelfernandes.org>
+ */
+
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/kthread.h>
+#include <linux/ktime.h>
+#include <linux/module.h>
+#include <linux/printk.h>
+#include <linux/string.h>
+
+static ulong delay = 100;
+static char test_mode[10] = "irq";
+
+module_param_named(delay, delay, ulong, S_IRUGO);
+module_param_string(test_mode, test_mode, 10, S_IRUGO);
+MODULE_PARM_DESC(delay, "Period in microseconds (100 uS default)");
+MODULE_PARM_DESC(test_mode, "Mode of the test such as preempt or irq (default irq)");
+
+static void busy_wait(ulong time)
+{
+	ktime_t start, end;
+	start = ktime_get();
+	do {
+		end = ktime_get();
+		if (kthread_should_stop())
+			break;
+	} while (ktime_to_ns(ktime_sub(end, start)) < (time * 1000));
+}
+
+int preemptirq_delay_run(void *data)
+{
+	unsigned long flags;
+
+	if (!strcmp(test_mode, "irq")) {
+		local_irq_save(flags);
+		busy_wait(delay);
+		local_irq_restore(flags);
+	} else if (!strcmp(test_mode, "preempt")) {
+		preempt_disable();
+		busy_wait(delay);
+		preempt_enable();
+	}
+
+	return 0;
+}
+
+static int __init preemptirq_delay_init(void)
+{
+	char task_name[50];
+	struct task_struct *test_task;
+
+	snprintf(task_name, sizeof(task_name), "%s_test", test_mode);
+
+	test_task = kthread_run(preemptirq_delay_run, NULL, task_name);
+	return PTR_ERR_OR_ZERO(test_task);
+}
+
+static void __exit preemptirq_delay_exit(void)
+{
+	return;
+}
+
+module_init(preemptirq_delay_init)
+module_exit(preemptirq_delay_exit)
+MODULE_LICENSE("GPL v2");
-- 
2.18.0

[for-next][PATCH 05/34] kselftests: Add tests for the preemptoff and irqsoff tracers

[Steven Rostedt]

From: "Joel Fernandes (Google)" <joel@joelfernandes.org>

Here we add unit tests for the preemptoff and irqsoff tracer by using a
kernel module introduced previously to trigger long preempt or irq
disabled sections in the kernel.

Link: http://lkml.kernel.org/r/20180711063540.91101-3-joel@joelfernandes.org

Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 tools/testing/selftests/ftrace/config         |  3 +
 .../test.d/preemptirq/irqsoff_tracer.tc       | 73 +++++++++++++++++++
 2 files changed, 76 insertions(+)
 create mode 100644 tools/testing/selftests/ftrace/test.d/preemptirq/irqsoff_tracer.tc

diff --git a/tools/testing/selftests/ftrace/config b/tools/testing/selftests/ftrace/config
index b01924c71c09..07db5ab09cc7 100644
--- a/tools/testing/selftests/ftrace/config
+++ b/tools/testing/selftests/ftrace/config
@@ -4,3 +4,6 @@ CONFIG_FUNCTION_PROFILER=y
 CONFIG_TRACER_SNAPSHOT=y
 CONFIG_STACK_TRACER=y
 CONFIG_HIST_TRIGGERS=y
+CONFIG_PREEMPT_TRACER=y
+CONFIG_IRQSOFF_TRACER=y
+CONFIG_PREEMPTIRQ_DELAY_TEST=m
diff --git a/tools/testing/selftests/ftrace/test.d/preemptirq/irqsoff_tracer.tc b/tools/testing/selftests/ftrace/test.d/preemptirq/irqsoff_tracer.tc
new file mode 100644
index 000000000000..cbd174334a48
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/preemptirq/irqsoff_tracer.tc
@@ -0,0 +1,73 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: test for the preemptirqsoff tracer
+
+MOD=preemptirq_delay_test
+
+fail() {
+    reset_tracer
+    rmmod $MOD || true
+    exit_fail
+}
+
+unsup() { #msg
+    reset_tracer
+    rmmod $MOD || true
+    echo $1
+    exit_unsupported
+}
+
+modprobe $MOD || unsup "$MOD module not available"
+rmmod $MOD
+
+grep -q "preemptoff" available_tracers || unsup "preemptoff tracer not enabled"
+grep -q "irqsoff" available_tracers || unsup "irqsoff tracer not enabled"
+
+reset_tracer
+
+# Simulate preemptoff section for half a second couple of times
+echo preemptoff > current_tracer
+sleep 1
+modprobe $MOD test_mode=preempt delay=500000 || fail
+rmmod $MOD || fail
+modprobe $MOD test_mode=preempt delay=500000 || fail
+rmmod $MOD || fail
+modprobe $MOD test_mode=preempt delay=500000 || fail
+rmmod $MOD || fail
+
+cat trace
+
+# Confirm which tracer
+grep -q "tracer: preemptoff" trace || fail
+
+# Check the end of the section
+egrep -q "5.....us : <stack trace>" trace || fail
+
+# Check for 500ms of latency
+egrep -q "latency: 5..... us" trace || fail
+
+reset_tracer
+
+# Simulate irqsoff section for half a second couple of times
+echo irqsoff > current_tracer
+sleep 1
+modprobe $MOD test_mode=irq delay=500000 || fail
+rmmod $MOD || fail
+modprobe $MOD test_mode=irq delay=500000 || fail
+rmmod $MOD || fail
+modprobe $MOD test_mode=irq delay=500000 || fail
+rmmod $MOD || fail
+
+cat trace
+
+# Confirm which tracer
+grep -q "tracer: irqsoff" trace || fail
+
+# Check the end of the section
+egrep -q "5.....us : <stack trace>" trace || fail
+
+# Check for 500ms of latency
+egrep -q "latency: 5..... us" trace || fail
+
+reset_tracer
+exit 0
-- 
2.18.0

[for-next][PATCH 06/34] tracing: Make unregister_trigger() static

[Steven Rostedt]

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

Nothing uses unregister_trigger() outside of trace_events_trigger.c file,
thus it should be static. Not sure why this was ever converted, because
its counter part, register_trigger(), was always static.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace.h                | 3 ---
 kernel/trace/trace_events_trigger.c | 6 +++---
 2 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index f8f86231ad90..3f9d9acc69e6 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1533,9 +1533,6 @@ extern int event_trigger_init(struct event_trigger_ops *ops,
 extern int trace_event_trigger_enable_disable(struct trace_event_file *file,
 					      int trigger_enable);
 extern void update_cond_flag(struct trace_event_file *file);
-extern void unregister_trigger(char *glob, struct event_trigger_ops *ops,
-			       struct event_trigger_data *test,
-			       struct trace_event_file *file);
 extern int set_trigger_filter(char *filter_str,
 			      struct event_trigger_data *trigger_data,
 			      struct trace_event_file *file);
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index 5dea177cef53..58d21fd52932 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -579,9 +579,9 @@ static int register_trigger(char *glob, struct event_trigger_ops *ops,
  * Usually used directly as the @unreg method in event command
  * implementations.
  */
-void unregister_trigger(char *glob, struct event_trigger_ops *ops,
-			struct event_trigger_data *test,
-			struct trace_event_file *file)
+static void unregister_trigger(char *glob, struct event_trigger_ops *ops,
+			       struct event_trigger_data *test,
+			       struct trace_event_file *file)
 {
 	struct event_trigger_data *data;
 	bool unregistered = false;
-- 
2.18.0

[for-next][PATCH 07/34] tracing: Remove orphaned function using_ftrace_ops_list_func().

[Steven Rostedt]

From: Masami Hiramatsu <mhiramat@kernel.org>

Remove using_ftrace_ops_list_func() since it is no longer used.

Using ftrace_ops_list_func() has been introduced by commit 7eea4fce0246
("tracing/stack_trace: Skip 4 instead of 3 when using ftrace_ops_list_func")
as a helper function, but its caller has been removed by commit 72ac426a5bb0
("tracing: Clean up stack tracing and fix fentry updates").  So it is not
called anymore.

Link: http://lkml.kernel.org/r/153260904427.12474.9952096317439329851.stgit@devbox

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c | 5 -----
 kernel/trace/trace.h  | 1 -
 2 files changed, 6 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index caf9cbf35816..b8b3324ca1c8 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -313,11 +313,6 @@ static void update_ftrace_function(void)
 	ftrace_trace_function = func;
 }
 
-int using_ftrace_ops_list_func(void)
-{
-	return ftrace_trace_function == ftrace_ops_list_func;
-}
-
 static void add_ftrace_ops(struct ftrace_ops __rcu **list,
 			   struct ftrace_ops *ops)
 {
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 3f9d9acc69e6..e1c8a1d6f240 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -937,7 +937,6 @@ void ftrace_destroy_function_files(struct trace_array *tr);
 void ftrace_init_global_array_ops(struct trace_array *tr);
 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func);
 void ftrace_reset_array_ops(struct trace_array *tr);
-int using_ftrace_ops_list_func(void);
 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer);
 void ftrace_init_tracefs_toplevel(struct trace_array *tr,
 				  struct dentry *d_tracer);
-- 
2.18.0

[for-next][PATCH 08/34] tracing: Remove orphaned function ftrace_nr_registered_ops()

[Steven Rostedt]

From: Masami Hiramatsu <mhiramat@kernel.org>

Remove ftrace_nr_registered_ops() because it is no longer used.

ftrace_nr_registered_ops() has been introduced by commit ea701f11da44
("ftrace: Add selftest to test function trace recursion protection"), but
its caller has been removed by commit 05cbbf643b8e ("tracing: Fix selftest
function recursion accounting"). So it is not called anymore.

Link: http://lkml.kernel.org/r/153260907227.12474.5234899025934963683.stgit@devbox

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/linux/ftrace.h |  6 ------
 kernel/trace/ftrace.c  | 24 ------------------------
 2 files changed, 30 deletions(-)

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index ebb77674be90..63af5eb0ff46 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -234,10 +234,6 @@ extern void ftrace_stub(unsigned long a0, unsigned long a1,
  */
 #define register_ftrace_function(ops) ({ 0; })
 #define unregister_ftrace_function(ops) ({ 0; })
-static inline int ftrace_nr_registered_ops(void)
-{
-	return 0;
-}
 static inline void ftrace_kill(void) { }
 static inline void ftrace_free_init_mem(void) { }
 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }
@@ -328,8 +324,6 @@ struct seq_file;
 
 extern int ftrace_text_reserved(const void *start, const void *end);
 
-extern int ftrace_nr_registered_ops(void);
-
 struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr);
 
 bool is_ftrace_trampoline(unsigned long addr);
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index b8b3324ca1c8..0d380a98a880 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -157,30 +157,6 @@ static inline void ftrace_ops_init(struct ftrace_ops *ops)
 #endif
 }
 
-/**
- * ftrace_nr_registered_ops - return number of ops registered
- *
- * Returns the number of ftrace_ops registered and tracing functions
- */
-int ftrace_nr_registered_ops(void)
-{
-	struct ftrace_ops *ops;
-	int cnt = 0;
-
-	mutex_lock(&ftrace_lock);
-
-	for (ops = rcu_dereference_protected(ftrace_ops_list,
-					     lockdep_is_held(&ftrace_lock));
-	     ops != &ftrace_list_end;
-	     ops = rcu_dereference_protected(ops->next,
-					     lockdep_is_held(&ftrace_lock)))
-		cnt++;
-
-	mutex_unlock(&ftrace_lock);
-
-	return cnt;
-}
-
 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
 			    struct ftrace_ops *op, struct pt_regs *regs)
 {
-- 
2.18.0

[for-next][PATCH 09/34] tracing/kprobes: Simplify the logic of enable_trace_kprobe()

[Steven Rostedt]

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

The function enable_trace_kprobe() performs slightly differently if the file
parameter is passed in as NULL on non-NULL. Instead of checking file twice,
move the code between the two tests into a static inline helper function to
make the code easier to follow.

Link: http://lkml.kernel.org/r/20180725224728.7b1d5db2@vmware.local.home
Link: http://lkml.kernel.org/r/20180726121152.4dd54330@gandalf.local.home

Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_kprobe.c | 42 +++++++++++++++++++++----------------
 1 file changed, 24 insertions(+), 18 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 6b71860f3998..0534eb8b7640 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -393,6 +393,20 @@ static struct trace_kprobe *find_trace_kprobe(const char *event,
 	return NULL;
 }
 
+static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
+{
+	int ret = 0;
+
+	if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
+		if (trace_kprobe_is_return(tk))
+			ret = enable_kretprobe(&tk->rp);
+		else
+			ret = enable_kprobe(&tk->rp.kp);
+	}
+
+	return ret;
+}
+
 /*
  * Enable trace_probe
  * if the file is NULL, enable "perf" handler, or enable "trace" handler.
@@ -400,7 +414,7 @@ static struct trace_kprobe *find_trace_kprobe(const char *event,
 static int
 enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
 {
-	struct event_file_link *link = NULL;
+	struct event_file_link *link;
 	int ret = 0;
 
 	if (file) {
@@ -414,26 +428,18 @@ enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
 		list_add_tail_rcu(&link->list, &tk->tp.files);
 
 		tk->tp.flags |= TP_FLAG_TRACE;
-	} else
-		tk->tp.flags |= TP_FLAG_PROFILE;
-
-	if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
-		if (trace_kprobe_is_return(tk))
-			ret = enable_kretprobe(&tk->rp);
-		else
-			ret = enable_kprobe(&tk->rp.kp);
-	}
-
-	if (ret) {
-		if (file) {
-			/* Notice the if is true on not WARN() */
-			if (!WARN_ON_ONCE(!link))
-				list_del_rcu(&link->list);
+		ret = __enable_trace_kprobe(tk);
+		if (ret) {
+			list_del_rcu(&link->list);
 			kfree(link);
 			tk->tp.flags &= ~TP_FLAG_TRACE;
-		} else {
-			tk->tp.flags &= ~TP_FLAG_PROFILE;
 		}
+
+	} else {
+		tk->tp.flags |= TP_FLAG_PROFILE;
+		ret = __enable_trace_kprobe(tk);
+		if (ret)
+			tk->tp.flags &= ~TP_FLAG_PROFILE;
 	}
  out:
 	return ret;
-- 
2.18.0

[for-next][PATCH 10/34] tracing: preemptirq_delay_run() can be static

[Steven Rostedt]

From: kbuild test robot <fengguang.wu@intel.com>

Automatically found by kbuild test robot.

Fixes: ffdc73a3b2ad ("lib: Add module for testing preemptoff/irqsoff latency tracers")
Signed-off-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/preemptirq_delay_test.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/preemptirq_delay_test.c b/kernel/trace/preemptirq_delay_test.c
index c97a026c0720..f704390db9fc 100644
--- a/kernel/trace/preemptirq_delay_test.c
+++ b/kernel/trace/preemptirq_delay_test.c
@@ -34,7 +34,7 @@ static void busy_wait(ulong time)
 	} while (ktime_to_ns(ktime_sub(end, start)) < (time * 1000));
 }
 
-int preemptirq_delay_run(void *data)
+static int preemptirq_delay_run(void *data)
 {
 	unsigned long flags;
 
-- 
2.18.0

[for-next][PATCH 11/34] tracing: kprobes: Prohibit probing on notrace function

[Steven Rostedt]

From: Masami Hiramatsu <mhiramat@kernel.org>

Prohibit kprobe-events probing on notrace functions.  Since probing on a
notrace function can cause a recursive event call. In most cases those are just
skipped, but in some cases it falls into an infinite recursive call.

This protection can be disabled by the kconfig
CONFIG_KPROBE_EVENTS_ON_NOTRACE=y, but it is highly recommended to keep it
"n" for normal kernel builds.  Note that this is only available if "kprobes on
ftrace" has been implemented on the target arch and CONFIG_KPROBES_ON_FTRACE=y.

Link: http://lkml.kernel.org/r/153294601436.32740.10557881188933661239.stgit@devbox

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Francis Deslauriers <francis.deslauriers@efficios.com>
[ Slight grammar and spelling fixes ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/Kconfig        | 20 ++++++++++++++++
 kernel/trace/trace_kprobe.c | 47 ++++++++++++++++++++++++++++++-------
 2 files changed, 58 insertions(+), 9 deletions(-)

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index e15fadbe5dfb..4d4eb15cc7fd 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -456,6 +456,26 @@ config KPROBE_EVENTS
 	  This option is also required by perf-probe subcommand of perf tools.
 	  If you want to use perf tools, this option is strongly recommended.
 
+config KPROBE_EVENTS_ON_NOTRACE
+	bool "Do NOT protect notrace function from kprobe events"
+	depends on KPROBE_EVENTS
+	depends on KPROBES_ON_FTRACE
+	default n
+	help
+	  This is only for the developers who want to debug ftrace itself
+	  using kprobe events.
+
+	  If kprobes can use ftrace instead of breakpoint, ftrace related
+	  functions are protected from kprobe-events to prevent an infinit
+	  recursion or any unexpected execution path which leads to a kernel
+	  crash.
+
+	  This option disables such protection and allows you to put kprobe
+	  events on ftrace functions for debugging ftrace by itself.
+	  Note that this might let you shoot yourself in the foot.
+
+	  If unsure, say N.
+
 config UPROBE_EVENTS
 	bool "Enable uprobes-based dynamic events"
 	depends on ARCH_SUPPORTS_UPROBES
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 0534eb8b7640..25662a780fdf 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -87,6 +87,21 @@ static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
 	return nhit;
 }
 
+static nokprobe_inline
+unsigned long trace_kprobe_address(struct trace_kprobe *tk)
+{
+	unsigned long addr;
+
+	if (tk->symbol) {
+		addr = (unsigned long)
+			kallsyms_lookup_name(trace_kprobe_symbol(tk));
+		addr += tk->rp.kp.offset;
+	} else {
+		addr = (unsigned long)tk->rp.kp.addr;
+	}
+	return addr;
+}
+
 bool trace_kprobe_on_func_entry(struct trace_event_call *call)
 {
 	struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
@@ -99,16 +114,8 @@ bool trace_kprobe_on_func_entry(struct trace_event_call *call)
 bool trace_kprobe_error_injectable(struct trace_event_call *call)
 {
 	struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
-	unsigned long addr;
 
-	if (tk->symbol) {
-		addr = (unsigned long)
-			kallsyms_lookup_name(trace_kprobe_symbol(tk));
-		addr += tk->rp.kp.offset;
-	} else {
-		addr = (unsigned long)tk->rp.kp.addr;
-	}
-	return within_error_injection_list(addr);
+	return within_error_injection_list(trace_kprobe_address(tk));
 }
 
 static int register_kprobe_event(struct trace_kprobe *tk);
@@ -504,6 +511,22 @@ disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
 	return ret;
 }
 
+#if defined(CONFIG_KPROBES_ON_FTRACE) && \
+	!defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
+static bool within_notrace_func(struct trace_kprobe *tk)
+{
+	unsigned long offset, size, addr;
+
+	addr = trace_kprobe_address(tk);
+	if (!kallsyms_lookup_size_offset(addr, &size, &offset))
+		return true;	/* Out of range. */
+
+	return !ftrace_location_range(addr - offset, addr - offset + size);
+}
+#else
+#define within_notrace_func(tk)	(false)
+#endif
+
 /* Internal register function - just handle k*probes and flags */
 static int __register_trace_kprobe(struct trace_kprobe *tk)
 {
@@ -512,6 +535,12 @@ static int __register_trace_kprobe(struct trace_kprobe *tk)
 	if (trace_probe_is_registered(&tk->tp))
 		return -EINVAL;
 
+	if (within_notrace_func(tk)) {
+		pr_warn("Could not probe notrace function %s\n",
+			trace_kprobe_symbol(tk));
+		return -EINVAL;
+	}
+
 	for (i = 0; i < tk->tp.nr_args; i++)
 		traceprobe_update_arg(&tk->tp.args[i]);
 
-- 
2.18.0

[for-next][PATCH 12/34] selftest/ftrace: Move kprobe selftest function to separate compile unit

[Steven Rostedt]

From: Francis Deslauriers <francis.deslauriers@efficios.com>

Move selftest function to its own compile unit so it can be compiled
with the ftrace cflags (CC_FLAGS_FTRACE) allowing it to be probed
during the ftrace startup tests.

Link: http://lkml.kernel.org/r/153294604271.32740.16490677128630177030.stgit@devbox

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/Makefile                |  5 +++++
 kernel/trace/trace_kprobe.c          | 12 +-----------
 kernel/trace/trace_kprobe_selftest.c | 10 ++++++++++
 kernel/trace/trace_kprobe_selftest.h |  7 +++++++
 4 files changed, 23 insertions(+), 11 deletions(-)
 create mode 100644 kernel/trace/trace_kprobe_selftest.c
 create mode 100644 kernel/trace/trace_kprobe_selftest.h

diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 31c6b524c260..81902a79e049 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -13,6 +13,11 @@ obj-y += trace_selftest_dynamic.o
 endif
 endif
 
+ifdef CONFIG_FTRACE_STARTUP_TEST
+CFLAGS_trace_kprobe_selftest.o = $(CC_FLAGS_FTRACE)
+obj-$(CONFIG_KPROBE_EVENTS) += trace_kprobe_selftest.o
+endif
+
 # If unlikely tracing is enabled, do not trace these files
 ifdef CONFIG_TRACING_BRANCHES
 KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 25662a780fdf..deeb03ae21e1 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -23,6 +23,7 @@
 #include <linux/rculist.h>
 #include <linux/error-injection.h>
 
+#include "trace_kprobe_selftest.h"
 #include "trace_probe.h"
 
 #define KPROBE_EVENT_SYSTEM "kprobes"
@@ -1587,17 +1588,6 @@ fs_initcall(init_kprobe_trace);
 
 
 #ifdef CONFIG_FTRACE_STARTUP_TEST
-/*
- * The "__used" keeps gcc from removing the function symbol
- * from the kallsyms table. 'noinline' makes sure that there
- * isn't an inlined version used by the test method below
- */
-static __used __init noinline int
-kprobe_trace_selftest_target(int a1, int a2, int a3, int a4, int a5, int a6)
-{
-	return a1 + a2 + a3 + a4 + a5 + a6;
-}
-
 static __init struct trace_event_file *
 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
 {
diff --git a/kernel/trace/trace_kprobe_selftest.c b/kernel/trace/trace_kprobe_selftest.c
new file mode 100644
index 000000000000..16548ee4c8c6
--- /dev/null
+++ b/kernel/trace/trace_kprobe_selftest.c
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Function used during the kprobe self test. This function is in a separate
+ * compile unit so it can be compile with CC_FLAGS_FTRACE to ensure that it
+ * can be probed by the selftests.
+ */
+int kprobe_trace_selftest_target(int a1, int a2, int a3, int a4, int a5, int a6)
+{
+	return a1 + a2 + a3 + a4 + a5 + a6;
+}
diff --git a/kernel/trace/trace_kprobe_selftest.h b/kernel/trace/trace_kprobe_selftest.h
new file mode 100644
index 000000000000..4e10ec41c013
--- /dev/null
+++ b/kernel/trace/trace_kprobe_selftest.h
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Function used during the kprobe self test. This function is in a separate
+ * compile unit so it can be compile with CC_FLAGS_FTRACE to ensure that it
+ * can be probed by the selftests.
+ */
+int kprobe_trace_selftest_target(int a1, int a2, int a3, int a4, int a5, int a6);
-- 
2.18.0

[for-next][PATCH 13/34] selftests/ftrace: Fix kprobe string testcase to not probe notrace function

[Steven Rostedt]

From: Masami Hiramatsu <mhiramat@kernel.org>

Fix kprobe string argument testcase to not probe notrace
function. Instead, it probes tracefs function which must
be available with ftrace.

Link: http://lkml.kernel.org/r/153294607107.32740.1664854684396589624.stgit@devbox

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 .../test.d/kprobe/kprobe_args_string.tc       | 30 ++++++++-----------
 .../ftrace/test.d/kprobe/probepoint.tc        |  2 +-
 2 files changed, 13 insertions(+), 19 deletions(-)

diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_string.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_string.tc
index a0002563e9ee..1ad70cdaf442 100644
--- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_string.tc
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_string.tc
@@ -9,28 +9,22 @@ echo > kprobe_events
 
 case `uname -m` in
 x86_64)
-  ARG2=%si
-  OFFS=8
+  ARG1=%di
 ;;
 i[3456]86)
-  ARG2=%cx
-  OFFS=4
+  ARG1=%ax
 ;;
 aarch64)
-  ARG2=%x1
-  OFFS=8
+  ARG1=%x0
 ;;
 arm*)
-  ARG2=%r1
-  OFFS=4
+  ARG1=%r0
 ;;
 ppc64*)
-  ARG2=%r4
-  OFFS=8
+  ARG1=%r3
 ;;
 ppc*)
-  ARG2=%r4
-  OFFS=4
+  ARG1=%r3
 ;;
 *)
   echo "Please implement other architecture here"
@@ -38,17 +32,17 @@ ppc*)
 esac
 
 : "Test get argument (1)"
-echo "p:testprobe create_trace_kprobe arg1=+0(+0(${ARG2})):string" > kprobe_events
+echo "p:testprobe tracefs_create_dir arg1=+0(${ARG1}):string" > kprobe_events
 echo 1 > events/kprobes/testprobe/enable
-! echo test >> kprobe_events
-tail -n 1 trace | grep -qe "testprobe.* arg1=\"test\""
+echo "p:test _do_fork" >> kprobe_events
+grep -qe "testprobe.* arg1=\"test\"" trace
 
 echo 0 > events/kprobes/testprobe/enable
 : "Test get argument (2)"
-echo "p:testprobe create_trace_kprobe arg1=+0(+0(${ARG2})):string arg2=+0(+${OFFS}(${ARG2})):string" > kprobe_events
+echo "p:testprobe tracefs_create_dir arg1=+0(${ARG1}):string arg2=+0(${ARG1}):string" > kprobe_events
 echo 1 > events/kprobes/testprobe/enable
-! echo test1 test2 >> kprobe_events
-tail -n 1 trace | grep -qe "testprobe.* arg1=\"test1\" arg2=\"test2\""
+echo "p:test _do_fork" >> kprobe_events
+grep -qe "testprobe.* arg1=\"test\" arg2=\"test\"" trace
 
 echo 0 > events/enable
 echo > kprobe_events
diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/probepoint.tc b/tools/testing/selftests/ftrace/test.d/kprobe/probepoint.tc
index 4fda01a08da4..519d2763f5d2 100644
--- a/tools/testing/selftests/ftrace/test.d/kprobe/probepoint.tc
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/probepoint.tc
@@ -4,7 +4,7 @@
 
 [ -f kprobe_events ] || exit_unsupported # this is configurable
 
-TARGET_FUNC=create_trace_kprobe
+TARGET_FUNC=tracefs_create_dir
 
 dec_addr() { # hexaddr
   printf "%d" "0x"`echo $1 | tail -c 8`
-- 
2.18.0

[for-next][PATCH 14/34] lockdep: Use this_cpu_ptr instead of get_cpu_var stats

[Steven Rostedt]

From: "Joel Fernandes (Google)" <joel@joelfernandes.org>

get_cpu_var disables preemption which has the potential to call into the
preemption disable trace points causing some complications. There's also
no need to disable preemption in uses of get_lock_stats anyway since
preempt is already disabled. So lets simplify the code.

Link: http://lkml.kernel.org/r/20180730222423.196630-2-joel@joelfernandes.org

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/locking/lockdep.c | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 5fa4d3138bf1..fbbb79d5cfa0 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -248,12 +248,7 @@ void clear_lock_stats(struct lock_class *class)
 
 static struct lock_class_stats *get_lock_stats(struct lock_class *class)
 {
-	return &get_cpu_var(cpu_lock_stats)[class - lock_classes];
-}
-
-static void put_lock_stats(struct lock_class_stats *stats)
-{
-	put_cpu_var(cpu_lock_stats);
+	return &this_cpu_ptr(cpu_lock_stats)[class - lock_classes];
 }
 
 static void lock_release_holdtime(struct held_lock *hlock)
@@ -271,7 +266,6 @@ static void lock_release_holdtime(struct held_lock *hlock)
 		lock_time_inc(&stats->read_holdtime, holdtime);
 	else
 		lock_time_inc(&stats->write_holdtime, holdtime);
-	put_lock_stats(stats);
 }
 #else
 static inline void lock_release_holdtime(struct held_lock *hlock)
@@ -4090,7 +4084,6 @@ __lock_contended(struct lockdep_map *lock, unsigned long ip)
 		stats->contending_point[contending_point]++;
 	if (lock->cpu != smp_processor_id())
 		stats->bounces[bounce_contended + !!hlock->read]++;
-	put_lock_stats(stats);
 }
 
 static void
@@ -4138,7 +4131,6 @@ __lock_acquired(struct lockdep_map *lock, unsigned long ip)
 	}
 	if (lock->cpu != cpu)
 		stats->bounces[bounce_acquired + !!hlock->read]++;
-	put_lock_stats(stats);
 
 	lock->cpu = cpu;
 	lock->ip = ip;
-- 
2.18.0

[for-next][PATCH 15/34] tracepoint: Make rcuidle tracepoint callers use SRCU

[Steven Rostedt]

From: "Joel Fernandes (Google)" <joel@joelfernandes.org>

In recent tests with IRQ on/off tracepoints, a large performance
overhead ~10% is noticed when running hackbench. This is root caused to
calls to rcu_irq_enter_irqson and rcu_irq_exit_irqson from the
tracepoint code. Following a long discussion on the list [1] about this,
we concluded that srcu is a better alternative for use during rcu idle.
Although it does involve extra barriers, its lighter than the sched-rcu
version which has to do additional RCU calls to notify RCU idle about
entry into RCU sections.

In this patch, we change the underlying implementation of the
trace_*_rcuidle API to use SRCU. This has shown to improve performance
alot for the high frequency irq enable/disable tracepoints.

Test: Tested idle and preempt/irq tracepoints.

Here are some performance numbers:

With a run of the following 30 times on a single core x86 Qemu instance
with 1GB memory:
hackbench -g 4 -f 2 -l 3000

Completion times in seconds. CONFIG_PROVE_LOCKING=y.

No patches (without this series)
Mean: 3.048
Median: 3.025
Std Dev: 0.064

With Lockdep using irq tracepoints with RCU implementation:
Mean: 3.451   (-11.66 %)
Median: 3.447 (-12.22%)
Std Dev: 0.049

With Lockdep using irq tracepoints with SRCU implementation (this series):
Mean: 3.020   (I would consider the improvement against the "without
	       this series" case as just noise).
Median: 3.013
Std Dev: 0.033

[1] https://patchwork.kernel.org/patch/10344297/

[remove rcu_read_lock_sched_notrace as its the equivalent of
preempt_disable_notrace and is unnecessary to call in tracepoint code]
Link: http://lkml.kernel.org/r/20180730222423.196630-3-joel@joelfernandes.org

Cleaned-up-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
[ Simplified WARN_ON_ONCE() ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/linux/tracepoint.h | 40 ++++++++++++++++++++++++++++++--------
 kernel/tracepoint.c        | 16 ++++++++++++++-
 2 files changed, 47 insertions(+), 9 deletions(-)

diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 19a690b559ca..d9a084c72541 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -15,6 +15,7 @@
  */
 
 #include <linux/smp.h>
+#include <linux/srcu.h>
 #include <linux/errno.h>
 #include <linux/types.h>
 #include <linux/cpumask.h>
@@ -33,6 +34,8 @@ struct trace_eval_map {
 
 #define TRACEPOINT_DEFAULT_PRIO	10
 
+extern struct srcu_struct tracepoint_srcu;
+
 extern int
 tracepoint_probe_register(struct tracepoint *tp, void *probe, void *data);
 extern int
@@ -75,10 +78,16 @@ int unregister_tracepoint_module_notifier(struct notifier_block *nb)
  * probe unregistration and the end of module exit to make sure there is no
  * caller executing a probe when it is freed.
  */
+#ifdef CONFIG_TRACEPOINTS
 static inline void tracepoint_synchronize_unregister(void)
 {
+	synchronize_srcu(&tracepoint_srcu);
 	synchronize_sched();
 }
+#else
+static inline void tracepoint_synchronize_unregister(void)
+{ }
+#endif
 
 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
 extern int syscall_regfunc(void);
@@ -129,18 +138,31 @@ extern void syscall_unregfunc(void);
  * as "(void *, void)". The DECLARE_TRACE_NOARGS() will pass in just
  * "void *data", where as the DECLARE_TRACE() will pass in "void *data, proto".
  */
-#define __DO_TRACE(tp, proto, args, cond, rcucheck)			\
+#define __DO_TRACE(tp, proto, args, cond, rcuidle)			\
 	do {								\
 		struct tracepoint_func *it_func_ptr;			\
 		void *it_func;						\
 		void *__data;						\
+		int __maybe_unused idx = 0;				\
 									\
 		if (!(cond))						\
 			return;						\
-		if (rcucheck)						\
-			rcu_irq_enter_irqson();				\
-		rcu_read_lock_sched_notrace();				\
-		it_func_ptr = rcu_dereference_sched((tp)->funcs);	\
+									\
+		/* srcu can't be used from NMI */			\
+		WARN_ON_ONCE(rcuidle && in_nmi());			\
+									\
+		/* keep srcu and sched-rcu usage consistent */		\
+		preempt_disable_notrace();				\
+									\
+		/*							\
+		 * For rcuidle callers, use srcu since sched-rcu	\
+		 * doesn't work from the idle path.			\
+		 */							\
+		if (rcuidle)						\
+			idx = srcu_read_lock_notrace(&tracepoint_srcu);	\
+									\
+		it_func_ptr = rcu_dereference_raw((tp)->funcs);		\
+									\
 		if (it_func_ptr) {					\
 			do {						\
 				it_func = (it_func_ptr)->func;		\
@@ -148,9 +170,11 @@ extern void syscall_unregfunc(void);
 				((void(*)(proto))(it_func))(args);	\
 			} while ((++it_func_ptr)->func);		\
 		}							\
-		rcu_read_unlock_sched_notrace();			\
-		if (rcucheck)						\
-			rcu_irq_exit_irqson();				\
+									\
+		if (rcuidle)						\
+			srcu_read_unlock_notrace(&tracepoint_srcu, idx);\
+									\
+		preempt_enable_notrace();				\
 	} while (0)
 
 #ifndef MODULE
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 6dc6356c3327..955148d91b74 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -31,6 +31,9 @@
 extern struct tracepoint * const __start___tracepoints_ptrs[];
 extern struct tracepoint * const __stop___tracepoints_ptrs[];
 
+DEFINE_SRCU(tracepoint_srcu);
+EXPORT_SYMBOL_GPL(tracepoint_srcu);
+
 /* Set to 1 to enable tracepoint debug output */
 static const int tracepoint_debug;
 
@@ -67,16 +70,27 @@ static inline void *allocate_probes(int count)
 	return p == NULL ? NULL : p->probes;
 }
 
-static void rcu_free_old_probes(struct rcu_head *head)
+static void srcu_free_old_probes(struct rcu_head *head)
 {
 	kfree(container_of(head, struct tp_probes, rcu));
 }
 
+static void rcu_free_old_probes(struct rcu_head *head)
+{
+	call_srcu(&tracepoint_srcu, head, srcu_free_old_probes);
+}
+
 static inline void release_probes(struct tracepoint_func *old)
 {
 	if (old) {
 		struct tp_probes *tp_probes = container_of(old,
 			struct tp_probes, probes[0]);
+		/*
+		 * Tracepoint probes are protected by both sched RCU and SRCU,
+		 * by calling the SRCU callback in the sched RCU callback we
+		 * cover both cases. So let us chain the SRCU and sched RCU
+		 * callbacks to wait for both grace periods.
+		 */
 		call_rcu_sched(&tp_probes->rcu, rcu_free_old_probes);
 	}
 }
-- 
2.18.0

[for-next][PATCH 16/34] tracing: Centralize preemptirq tracepoints and unify their usage

[Steven Rostedt]

From: "Joel Fernandes (Google)" <joel@joelfernandes.org>

This patch detaches the preemptirq tracepoints from the tracers and
keeps it separate.

Advantages:
* Lockdep and irqsoff event can now run in parallel since they no longer
have their own calls.

* This unifies the usecase of adding hooks to an irqsoff and irqson
event, and a preemptoff and preempton event.
  3 users of the events exist:
  - Lockdep
  - irqsoff and preemptoff tracers
  - irqs and preempt trace events

The unification cleans up several ifdefs and makes the code in preempt
tracer and irqsoff tracers simpler. It gets rid of all the horrific
ifdeferry around PROVE_LOCKING and makes configuration of the different
users of the tracepoints more easy and understandable. It also gets rid
of the time_* function calls from the lockdep hooks used to call into
the preemptirq tracer which is not needed anymore. The negative delta in
lines of code in this patch is quite large too.

In the patch we introduce a new CONFIG option PREEMPTIRQ_TRACEPOINTS
as a single point for registering probes onto the tracepoints. With
this,
the web of config options for preempt/irq toggle tracepoints and its
users becomes:

 PREEMPT_TRACER   PREEMPTIRQ_EVENTS  IRQSOFF_TRACER PROVE_LOCKING
       |                 |     \         |           |
       \    (selects)    /      \        \ (selects) /
      TRACE_PREEMPT_TOGGLE       ----> TRACE_IRQFLAGS
                      \                  /
                       \ (depends on)   /
                     PREEMPTIRQ_TRACEPOINTS

Other than the performance tests mentioned in the previous patch, I also
ran the locking API test suite. I verified that all tests cases are
passing.

I also injected issues by not registering lockdep probes onto the
tracepoints and I see failures to confirm that the probes are indeed
working.

This series + lockdep probes not registered (just to inject errors):
[    0.000000]      hard-irqs-on + irq-safe-A/21:  ok  |  ok  |  ok  |
[    0.000000]      soft-irqs-on + irq-safe-A/21:  ok  |  ok  |  ok  |
[    0.000000]        sirq-safe-A => hirqs-on/12:FAILED|FAILED|  ok  |
[    0.000000]        sirq-safe-A => hirqs-on/21:FAILED|FAILED|  ok  |
[    0.000000]          hard-safe-A + irqs-on/12:FAILED|FAILED|  ok  |
[    0.000000]          soft-safe-A + irqs-on/12:FAILED|FAILED|  ok  |
[    0.000000]          hard-safe-A + irqs-on/21:FAILED|FAILED|  ok  |
[    0.000000]          soft-safe-A + irqs-on/21:FAILED|FAILED|  ok  |
[    0.000000]     hard-safe-A + unsafe-B #1/123:  ok  |  ok  |  ok  |
[    0.000000]     soft-safe-A + unsafe-B #1/123:  ok  |  ok  |  ok  |

With this series + lockdep probes registered, all locking tests pass:

[    0.000000]      hard-irqs-on + irq-safe-A/21:  ok  |  ok  |  ok  |
[    0.000000]      soft-irqs-on + irq-safe-A/21:  ok  |  ok  |  ok  |
[    0.000000]        sirq-safe-A => hirqs-on/12:  ok  |  ok  |  ok  |
[    0.000000]        sirq-safe-A => hirqs-on/21:  ok  |  ok  |  ok  |
[    0.000000]          hard-safe-A + irqs-on/12:  ok  |  ok  |  ok  |
[    0.000000]          soft-safe-A + irqs-on/12:  ok  |  ok  |  ok  |
[    0.000000]          hard-safe-A + irqs-on/21:  ok  |  ok  |  ok  |
[    0.000000]          soft-safe-A + irqs-on/21:  ok  |  ok  |  ok  |
[    0.000000]     hard-safe-A + unsafe-B #1/123:  ok  |  ok  |  ok  |
[    0.000000]     soft-safe-A + unsafe-B #1/123:  ok  |  ok  |  ok  |

Link: http://lkml.kernel.org/r/20180730222423.196630-4-joel@joelfernandes.org

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/linux/ftrace.h            |  11 +-
 include/linux/irqflags.h          |  11 +-
 include/linux/lockdep.h           |   8 +-
 include/linux/preempt.h           |   2 +-
 include/trace/events/preemptirq.h |  23 +--
 init/main.c                       |   5 +-
 kernel/locking/lockdep.c          |  35 ++---
 kernel/sched/core.c               |   2 +-
 kernel/trace/Kconfig              |  22 ++-
 kernel/trace/Makefile             |   2 +-
 kernel/trace/trace_irqsoff.c      | 231 ++++++++----------------------
 kernel/trace/trace_preemptirq.c   |  72 ++++++++++
 12 files changed, 195 insertions(+), 229 deletions(-)
 create mode 100644 kernel/trace/trace_preemptirq.c

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 63af5eb0ff46..a397907e8d72 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -701,16 +701,7 @@ static inline unsigned long get_lock_parent_ip(void)
 	return CALLER_ADDR2;
 }
 
-#ifdef CONFIG_IRQSOFF_TRACER
-  extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
-  extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
-#else
-  static inline void time_hardirqs_on(unsigned long a0, unsigned long a1) { }
-  static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
-#endif
-
-#if defined(CONFIG_PREEMPT_TRACER) || \
-	(defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_PREEMPTIRQ_EVENTS))
+#ifdef CONFIG_TRACE_PREEMPT_TOGGLE
   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 #else
diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h
index 9700f00bbc04..50edb9cbbd26 100644
--- a/include/linux/irqflags.h
+++ b/include/linux/irqflags.h
@@ -15,9 +15,16 @@
 #include <linux/typecheck.h>
 #include <asm/irqflags.h>
 
-#ifdef CONFIG_TRACE_IRQFLAGS
+/* Currently trace_softirqs_on/off is used only by lockdep */
+#ifdef CONFIG_PROVE_LOCKING
   extern void trace_softirqs_on(unsigned long ip);
   extern void trace_softirqs_off(unsigned long ip);
+#else
+# define trace_softirqs_on(ip)	do { } while (0)
+# define trace_softirqs_off(ip)	do { } while (0)
+#endif
+
+#ifdef CONFIG_TRACE_IRQFLAGS
   extern void trace_hardirqs_on(void);
   extern void trace_hardirqs_off(void);
 # define trace_hardirq_context(p)	((p)->hardirq_context)
@@ -43,8 +50,6 @@ do {						\
 #else
 # define trace_hardirqs_on()		do { } while (0)
 # define trace_hardirqs_off()		do { } while (0)
-# define trace_softirqs_on(ip)		do { } while (0)
-# define trace_softirqs_off(ip)		do { } while (0)
 # define trace_hardirq_context(p)	0
 # define trace_softirq_context(p)	0
 # define trace_hardirqs_enabled(p)	0
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 6fc77d4dbdcd..a8113357ceeb 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -266,7 +266,8 @@ struct held_lock {
 /*
  * Initialization, self-test and debugging-output methods:
  */
-extern void lockdep_info(void);
+extern void lockdep_init(void);
+extern void lockdep_init_early(void);
 extern void lockdep_reset(void);
 extern void lockdep_reset_lock(struct lockdep_map *lock);
 extern void lockdep_free_key_range(void *start, unsigned long size);
@@ -406,7 +407,8 @@ static inline void lockdep_on(void)
 # define lock_downgrade(l, i)			do { } while (0)
 # define lock_set_class(l, n, k, s, i)		do { } while (0)
 # define lock_set_subclass(l, s, i)		do { } while (0)
-# define lockdep_info()				do { } while (0)
+# define lockdep_init()				do { } while (0)
+# define lockdep_init_early()			do { } while (0)
 # define lockdep_init_map(lock, name, key, sub) \
 		do { (void)(name); (void)(key); } while (0)
 # define lockdep_set_class(lock, key)		do { (void)(key); } while (0)
@@ -532,7 +534,7 @@ do {								\
 
 #endif /* CONFIG_LOCKDEP */
 
-#ifdef CONFIG_TRACE_IRQFLAGS
+#ifdef CONFIG_PROVE_LOCKING
 extern void print_irqtrace_events(struct task_struct *curr);
 #else
 static inline void print_irqtrace_events(struct task_struct *curr)
diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 5bd3f151da78..c01813c3fbe9 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -150,7 +150,7 @@
  */
 #define in_atomic_preempt_off() (preempt_count() != PREEMPT_DISABLE_OFFSET)
 
-#if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_PREEMPT_TRACER)
+#if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_TRACE_PREEMPT_TOGGLE)
 extern void preempt_count_add(int val);
 extern void preempt_count_sub(int val);
 #define preempt_count_dec_and_test() \
diff --git a/include/trace/events/preemptirq.h b/include/trace/events/preemptirq.h
index 9c4eb33c5a1d..9a0d4ceeb166 100644
--- a/include/trace/events/preemptirq.h
+++ b/include/trace/events/preemptirq.h
@@ -1,4 +1,4 @@
-#ifdef CONFIG_PREEMPTIRQ_EVENTS
+#ifdef CONFIG_PREEMPTIRQ_TRACEPOINTS
 
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM preemptirq
@@ -32,7 +32,7 @@ DECLARE_EVENT_CLASS(preemptirq_template,
 		  (void *)((unsigned long)(_stext) + __entry->parent_offs))
 );
 
-#ifndef CONFIG_PROVE_LOCKING
+#ifdef CONFIG_TRACE_IRQFLAGS
 DEFINE_EVENT(preemptirq_template, irq_disable,
 	     TP_PROTO(unsigned long ip, unsigned long parent_ip),
 	     TP_ARGS(ip, parent_ip));
@@ -40,9 +40,14 @@ DEFINE_EVENT(preemptirq_template, irq_disable,
 DEFINE_EVENT(preemptirq_template, irq_enable,
 	     TP_PROTO(unsigned long ip, unsigned long parent_ip),
 	     TP_ARGS(ip, parent_ip));
+#else
+#define trace_irq_enable(...)
+#define trace_irq_disable(...)
+#define trace_irq_enable_rcuidle(...)
+#define trace_irq_disable_rcuidle(...)
 #endif
 
-#ifdef CONFIG_DEBUG_PREEMPT
+#ifdef CONFIG_TRACE_PREEMPT_TOGGLE
 DEFINE_EVENT(preemptirq_template, preempt_disable,
 	     TP_PROTO(unsigned long ip, unsigned long parent_ip),
 	     TP_ARGS(ip, parent_ip));
@@ -50,22 +55,22 @@ DEFINE_EVENT(preemptirq_template, preempt_disable,
 DEFINE_EVENT(preemptirq_template, preempt_enable,
 	     TP_PROTO(unsigned long ip, unsigned long parent_ip),
 	     TP_ARGS(ip, parent_ip));
+#else
+#define trace_preempt_enable(...)
+#define trace_preempt_disable(...)
+#define trace_preempt_enable_rcuidle(...)
+#define trace_preempt_disable_rcuidle(...)
 #endif
 
 #endif /* _TRACE_PREEMPTIRQ_H */
 
 #include <trace/define_trace.h>
 
-#endif /* !CONFIG_PREEMPTIRQ_EVENTS */
-
-#if !defined(CONFIG_PREEMPTIRQ_EVENTS) || defined(CONFIG_PROVE_LOCKING)
+#else /* !CONFIG_PREEMPTIRQ_TRACEPOINTS */
 #define trace_irq_enable(...)
 #define trace_irq_disable(...)
 #define trace_irq_enable_rcuidle(...)
 #define trace_irq_disable_rcuidle(...)
-#endif
-
-#if !defined(CONFIG_PREEMPTIRQ_EVENTS) || !defined(CONFIG_DEBUG_PREEMPT)
 #define trace_preempt_enable(...)
 #define trace_preempt_disable(...)
 #define trace_preempt_enable_rcuidle(...)
diff --git a/init/main.c b/init/main.c
index 3b4ada11ed52..44fe43be84c1 100644
--- a/init/main.c
+++ b/init/main.c
@@ -648,6 +648,9 @@ asmlinkage __visible void __init start_kernel(void)
 	profile_init();
 	call_function_init();
 	WARN(!irqs_disabled(), "Interrupts were enabled early\n");
+
+	lockdep_init_early();
+
 	early_boot_irqs_disabled = false;
 	local_irq_enable();
 
@@ -663,7 +666,7 @@ asmlinkage __visible void __init start_kernel(void)
 		panic("Too many boot %s vars at `%s'", panic_later,
 		      panic_param);
 
-	lockdep_info();
+	lockdep_init();
 
 	/*
 	 * Need to run this when irqs are enabled, because it wants
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index fbbb79d5cfa0..03bfaeb9f4e6 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -55,6 +55,7 @@
 
 #include "lockdep_internals.h"
 
+#include <trace/events/preemptirq.h>
 #define CREATE_TRACE_POINTS
 #include <trace/events/lock.h>
 
@@ -2839,10 +2840,9 @@ static void __trace_hardirqs_on_caller(unsigned long ip)
 	debug_atomic_inc(hardirqs_on_events);
 }
 
-__visible void trace_hardirqs_on_caller(unsigned long ip)
+static void lockdep_hardirqs_on(void *none, unsigned long ignore,
+				unsigned long ip)
 {
-	time_hardirqs_on(CALLER_ADDR0, ip);
-
 	if (unlikely(!debug_locks || current->lockdep_recursion))
 		return;
 
@@ -2881,23 +2881,15 @@ __visible void trace_hardirqs_on_caller(unsigned long ip)
 	__trace_hardirqs_on_caller(ip);
 	current->lockdep_recursion = 0;
 }
-EXPORT_SYMBOL(trace_hardirqs_on_caller);
-
-void trace_hardirqs_on(void)
-{
-	trace_hardirqs_on_caller(CALLER_ADDR0);
-}
-EXPORT_SYMBOL(trace_hardirqs_on);
 
 /*
  * Hardirqs were disabled:
  */
-__visible void trace_hardirqs_off_caller(unsigned long ip)
+static void lockdep_hardirqs_off(void *none, unsigned long ignore,
+				 unsigned long ip)
 {
 	struct task_struct *curr = current;
 
-	time_hardirqs_off(CALLER_ADDR0, ip);
-
 	if (unlikely(!debug_locks || current->lockdep_recursion))
 		return;
 
@@ -2919,13 +2911,6 @@ __visible void trace_hardirqs_off_caller(unsigned long ip)
 	} else
 		debug_atomic_inc(redundant_hardirqs_off);
 }
-EXPORT_SYMBOL(trace_hardirqs_off_caller);
-
-void trace_hardirqs_off(void)
-{
-	trace_hardirqs_off_caller(CALLER_ADDR0);
-}
-EXPORT_SYMBOL(trace_hardirqs_off);
 
 /*
  * Softirqs will be enabled:
@@ -4330,7 +4315,15 @@ void lockdep_reset_lock(struct lockdep_map *lock)
 	raw_local_irq_restore(flags);
 }
 
-void __init lockdep_info(void)
+void __init lockdep_init_early(void)
+{
+#ifdef CONFIG_PROVE_LOCKING
+	register_trace_prio_irq_disable(lockdep_hardirqs_off, NULL, INT_MAX);
+	register_trace_prio_irq_enable(lockdep_hardirqs_on, NULL, INT_MIN);
+#endif
+}
+
+void __init lockdep_init(void)
 {
 	printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n");
 
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index fe365c9a08e9..5de1a4343424 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3189,7 +3189,7 @@ static inline void sched_tick_stop(int cpu) { }
 #endif
 
 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
-				defined(CONFIG_PREEMPT_TRACER))
+				defined(CONFIG_TRACE_PREEMPT_TOGGLE))
 /*
  * If the value passed in is equal to the current preempt count
  * then we just disabled preemption. Start timing the latency.
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 4d4eb15cc7fd..036cec1fcd24 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -82,6 +82,15 @@ config RING_BUFFER_ALLOW_SWAP
 	 Allow the use of ring_buffer_swap_cpu.
 	 Adds a very slight overhead to tracing when enabled.
 
+config PREEMPTIRQ_TRACEPOINTS
+	bool
+	depends on TRACE_PREEMPT_TOGGLE || TRACE_IRQFLAGS
+	select TRACING
+	default y
+	help
+	  Create preempt/irq toggle tracepoints if needed, so that other parts
+	  of the kernel can use them to generate or add hooks to them.
+
 # All tracer options should select GENERIC_TRACER. For those options that are
 # enabled by all tracers (context switch and event tracer) they select TRACING.
 # This allows those options to appear when no other tracer is selected. But the
@@ -155,18 +164,20 @@ config FUNCTION_GRAPH_TRACER
 	  the return value. This is done by setting the current return
 	  address on the current task structure into a stack of calls.
 
+config TRACE_PREEMPT_TOGGLE
+	bool
+	help
+	  Enables hooks which will be called when preemption is first disabled,
+	  and last enabled.
 
 config PREEMPTIRQ_EVENTS
 	bool "Enable trace events for preempt and irq disable/enable"
 	select TRACE_IRQFLAGS
-	depends on DEBUG_PREEMPT || !PROVE_LOCKING
-	depends on TRACING
+	select TRACE_PREEMPT_TOGGLE if PREEMPT
+	select GENERIC_TRACER
 	default n
 	help
 	  Enable tracing of disable and enable events for preemption and irqs.
-	  For tracing preempt disable/enable events, DEBUG_PREEMPT must be
-	  enabled. For tracing irq disable/enable events, PROVE_LOCKING must
-	  be disabled.
 
 config IRQSOFF_TRACER
 	bool "Interrupts-off Latency Tracer"
@@ -203,6 +214,7 @@ config PREEMPT_TRACER
 	select RING_BUFFER_ALLOW_SWAP
 	select TRACER_SNAPSHOT
 	select TRACER_SNAPSHOT_PER_CPU_SWAP
+	select TRACE_PREEMPT_TOGGLE
 	help
 	  This option measures the time spent in preemption-off critical
 	  sections, with microsecond accuracy.
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 81902a79e049..98d53b39a8ee 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -41,7 +41,7 @@ obj-$(CONFIG_TRACING_MAP) += tracing_map.o
 obj-$(CONFIG_PREEMPTIRQ_DELAY_TEST) += preemptirq_delay_test.o
 obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
 obj-$(CONFIG_FUNCTION_TRACER) += trace_functions.o
-obj-$(CONFIG_PREEMPTIRQ_EVENTS) += trace_irqsoff.o
+obj-$(CONFIG_PREEMPTIRQ_TRACEPOINTS) += trace_preemptirq.o
 obj-$(CONFIG_IRQSOFF_TRACER) += trace_irqsoff.o
 obj-$(CONFIG_PREEMPT_TRACER) += trace_irqsoff.o
 obj-$(CONFIG_SCHED_TRACER) += trace_sched_wakeup.o
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index f8daa754cce2..770cd30cda40 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -16,7 +16,6 @@
 
 #include "trace.h"
 
-#define CREATE_TRACE_POINTS
 #include <trace/events/preemptirq.h>
 
 #if defined(CONFIG_IRQSOFF_TRACER) || defined(CONFIG_PREEMPT_TRACER)
@@ -450,66 +449,6 @@ void stop_critical_timings(void)
 }
 EXPORT_SYMBOL_GPL(stop_critical_timings);
 
-#ifdef CONFIG_IRQSOFF_TRACER
-#ifdef CONFIG_PROVE_LOCKING
-void time_hardirqs_on(unsigned long a0, unsigned long a1)
-{
-	if (!preempt_trace() && irq_trace())
-		stop_critical_timing(a0, a1);
-}
-
-void time_hardirqs_off(unsigned long a0, unsigned long a1)
-{
-	if (!preempt_trace() && irq_trace())
-		start_critical_timing(a0, a1);
-}
-
-#else /* !CONFIG_PROVE_LOCKING */
-
-/*
- * We are only interested in hardirq on/off events:
- */
-static inline void tracer_hardirqs_on(void)
-{
-	if (!preempt_trace() && irq_trace())
-		stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
-}
-
-static inline void tracer_hardirqs_off(void)
-{
-	if (!preempt_trace() && irq_trace())
-		start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
-}
-
-static inline void tracer_hardirqs_on_caller(unsigned long caller_addr)
-{
-	if (!preempt_trace() && irq_trace())
-		stop_critical_timing(CALLER_ADDR0, caller_addr);
-}
-
-static inline void tracer_hardirqs_off_caller(unsigned long caller_addr)
-{
-	if (!preempt_trace() && irq_trace())
-		start_critical_timing(CALLER_ADDR0, caller_addr);
-}
-
-#endif /* CONFIG_PROVE_LOCKING */
-#endif /*  CONFIG_IRQSOFF_TRACER */
-
-#ifdef CONFIG_PREEMPT_TRACER
-static inline void tracer_preempt_on(unsigned long a0, unsigned long a1)
-{
-	if (preempt_trace() && !irq_trace())
-		stop_critical_timing(a0, a1);
-}
-
-static inline void tracer_preempt_off(unsigned long a0, unsigned long a1)
-{
-	if (preempt_trace() && !irq_trace())
-		start_critical_timing(a0, a1);
-}
-#endif /* CONFIG_PREEMPT_TRACER */
-
 #ifdef CONFIG_FUNCTION_TRACER
 static bool function_enabled;
 
@@ -659,15 +598,34 @@ static void irqsoff_tracer_stop(struct trace_array *tr)
 }
 
 #ifdef CONFIG_IRQSOFF_TRACER
+/*
+ * We are only interested in hardirq on/off events:
+ */
+static void tracer_hardirqs_on(void *none, unsigned long a0, unsigned long a1)
+{
+	if (!preempt_trace() && irq_trace())
+		stop_critical_timing(a0, a1);
+}
+
+static void tracer_hardirqs_off(void *none, unsigned long a0, unsigned long a1)
+{
+	if (!preempt_trace() && irq_trace())
+		start_critical_timing(a0, a1);
+}
+
 static int irqsoff_tracer_init(struct trace_array *tr)
 {
 	trace_type = TRACER_IRQS_OFF;
 
+	register_trace_irq_disable(tracer_hardirqs_off, NULL);
+	register_trace_irq_enable(tracer_hardirqs_on, NULL);
 	return __irqsoff_tracer_init(tr);
 }
 
 static void irqsoff_tracer_reset(struct trace_array *tr)
 {
+	unregister_trace_irq_disable(tracer_hardirqs_off, NULL);
+	unregister_trace_irq_enable(tracer_hardirqs_on, NULL);
 	__irqsoff_tracer_reset(tr);
 }
 
@@ -690,21 +648,34 @@ static struct tracer irqsoff_tracer __read_mostly =
 	.allow_instances = true,
 	.use_max_tr	= true,
 };
-# define register_irqsoff(trace) register_tracer(&trace)
-#else
-# define register_irqsoff(trace) do { } while (0)
-#endif
+#endif /*  CONFIG_IRQSOFF_TRACER */
 
 #ifdef CONFIG_PREEMPT_TRACER
+static void tracer_preempt_on(void *none, unsigned long a0, unsigned long a1)
+{
+	if (preempt_trace() && !irq_trace())
+		stop_critical_timing(a0, a1);
+}
+
+static void tracer_preempt_off(void *none, unsigned long a0, unsigned long a1)
+{
+	if (preempt_trace() && !irq_trace())
+		start_critical_timing(a0, a1);
+}
+
 static int preemptoff_tracer_init(struct trace_array *tr)
 {
 	trace_type = TRACER_PREEMPT_OFF;
 
+	register_trace_preempt_disable(tracer_preempt_off, NULL);
+	register_trace_preempt_enable(tracer_preempt_on, NULL);
 	return __irqsoff_tracer_init(tr);
 }
 
 static void preemptoff_tracer_reset(struct trace_array *tr)
 {
+	unregister_trace_preempt_disable(tracer_preempt_off, NULL);
+	unregister_trace_preempt_enable(tracer_preempt_on, NULL);
 	__irqsoff_tracer_reset(tr);
 }
 
@@ -727,23 +698,29 @@ static struct tracer preemptoff_tracer __read_mostly =
 	.allow_instances = true,
 	.use_max_tr	= true,
 };
-# define register_preemptoff(trace) register_tracer(&trace)
-#else
-# define register_preemptoff(trace) do { } while (0)
-#endif
+#endif /* CONFIG_PREEMPT_TRACER */
 
-#if defined(CONFIG_IRQSOFF_TRACER) && \
-	defined(CONFIG_PREEMPT_TRACER)
+#if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
 
 static int preemptirqsoff_tracer_init(struct trace_array *tr)
 {
 	trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF;
 
+	register_trace_irq_disable(tracer_hardirqs_off, NULL);
+	register_trace_irq_enable(tracer_hardirqs_on, NULL);
+	register_trace_preempt_disable(tracer_preempt_off, NULL);
+	register_trace_preempt_enable(tracer_preempt_on, NULL);
+
 	return __irqsoff_tracer_init(tr);
 }
 
 static void preemptirqsoff_tracer_reset(struct trace_array *tr)
 {
+	unregister_trace_irq_disable(tracer_hardirqs_off, NULL);
+	unregister_trace_irq_enable(tracer_hardirqs_on, NULL);
+	unregister_trace_preempt_disable(tracer_preempt_off, NULL);
+	unregister_trace_preempt_enable(tracer_preempt_on, NULL);
+
 	__irqsoff_tracer_reset(tr);
 }
 
@@ -766,115 +743,21 @@ static struct tracer preemptirqsoff_tracer __read_mostly =
 	.allow_instances = true,
 	.use_max_tr	= true,
 };
-
-# define register_preemptirqsoff(trace) register_tracer(&trace)
-#else
-# define register_preemptirqsoff(trace) do { } while (0)
 #endif
 
 __init static int init_irqsoff_tracer(void)
 {
-	register_irqsoff(irqsoff_tracer);
-	register_preemptoff(preemptoff_tracer);
-	register_preemptirqsoff(preemptirqsoff_tracer);
-
-	return 0;
-}
-core_initcall(init_irqsoff_tracer);
-#endif /* IRQSOFF_TRACER || PREEMPTOFF_TRACER */
-
-#ifndef CONFIG_IRQSOFF_TRACER
-static inline void tracer_hardirqs_on(void) { }
-static inline void tracer_hardirqs_off(void) { }
-static inline void tracer_hardirqs_on_caller(unsigned long caller_addr) { }
-static inline void tracer_hardirqs_off_caller(unsigned long caller_addr) { }
+#ifdef CONFIG_IRQSOFF_TRACER
+	register_tracer(&irqsoff_tracer);
 #endif
-
-#ifndef CONFIG_PREEMPT_TRACER
-static inline void tracer_preempt_on(unsigned long a0, unsigned long a1) { }
-static inline void tracer_preempt_off(unsigned long a0, unsigned long a1) { }
+#ifdef CONFIG_PREEMPT_TRACER
+	register_tracer(&preemptoff_tracer);
 #endif
-
-#if defined(CONFIG_TRACE_IRQFLAGS) && !defined(CONFIG_PROVE_LOCKING)
-/* Per-cpu variable to prevent redundant calls when IRQs already off */
-static DEFINE_PER_CPU(int, tracing_irq_cpu);
-
-void trace_hardirqs_on(void)
-{
-	if (!this_cpu_read(tracing_irq_cpu))
-		return;
-
-	trace_irq_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
-	tracer_hardirqs_on();
-
-	this_cpu_write(tracing_irq_cpu, 0);
-}
-EXPORT_SYMBOL(trace_hardirqs_on);
-
-void trace_hardirqs_off(void)
-{
-	if (this_cpu_read(tracing_irq_cpu))
-		return;
-
-	this_cpu_write(tracing_irq_cpu, 1);
-
-	trace_irq_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
-	tracer_hardirqs_off();
-}
-EXPORT_SYMBOL(trace_hardirqs_off);
-
-__visible void trace_hardirqs_on_caller(unsigned long caller_addr)
-{
-	if (!this_cpu_read(tracing_irq_cpu))
-		return;
-
-	trace_irq_enable_rcuidle(CALLER_ADDR0, caller_addr);
-	tracer_hardirqs_on_caller(caller_addr);
-
-	this_cpu_write(tracing_irq_cpu, 0);
-}
-EXPORT_SYMBOL(trace_hardirqs_on_caller);
-
-__visible void trace_hardirqs_off_caller(unsigned long caller_addr)
-{
-	if (this_cpu_read(tracing_irq_cpu))
-		return;
-
-	this_cpu_write(tracing_irq_cpu, 1);
-
-	trace_irq_disable_rcuidle(CALLER_ADDR0, caller_addr);
-	tracer_hardirqs_off_caller(caller_addr);
-}
-EXPORT_SYMBOL(trace_hardirqs_off_caller);
-
-/*
- * Stubs:
- */
-
-void trace_softirqs_on(unsigned long ip)
-{
-}
-
-void trace_softirqs_off(unsigned long ip)
-{
-}
-
-inline void print_irqtrace_events(struct task_struct *curr)
-{
-}
+#if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
+	register_tracer(&preemptirqsoff_tracer);
 #endif
 
-#if defined(CONFIG_PREEMPT_TRACER) || \
-	(defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_PREEMPTIRQ_EVENTS))
-void trace_preempt_on(unsigned long a0, unsigned long a1)
-{
-	trace_preempt_enable_rcuidle(a0, a1);
-	tracer_preempt_on(a0, a1);
-}
-
-void trace_preempt_off(unsigned long a0, unsigned long a1)
-{
-	trace_preempt_disable_rcuidle(a0, a1);
-	tracer_preempt_off(a0, a1);
+	return 0;
 }
-#endif
+core_initcall(init_irqsoff_tracer);
+#endif /* IRQSOFF_TRACER || PREEMPTOFF_TRACER */
diff --git a/kernel/trace/trace_preemptirq.c b/kernel/trace/trace_preemptirq.c
new file mode 100644
index 000000000000..e76b78bf258e
--- /dev/null
+++ b/kernel/trace/trace_preemptirq.c
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * preemptoff and irqoff tracepoints
+ *
+ * Copyright (C) Joel Fernandes (Google) <joel@joelfernandes.org>
+ */
+
+#include <linux/kallsyms.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/ftrace.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/preemptirq.h>
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+/* Per-cpu variable to prevent redundant calls when IRQs already off */
+static DEFINE_PER_CPU(int, tracing_irq_cpu);
+
+void trace_hardirqs_on(void)
+{
+	if (!this_cpu_read(tracing_irq_cpu))
+		return;
+
+	trace_irq_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
+	this_cpu_write(tracing_irq_cpu, 0);
+}
+EXPORT_SYMBOL(trace_hardirqs_on);
+
+void trace_hardirqs_off(void)
+{
+	if (this_cpu_read(tracing_irq_cpu))
+		return;
+
+	this_cpu_write(tracing_irq_cpu, 1);
+	trace_irq_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
+}
+EXPORT_SYMBOL(trace_hardirqs_off);
+
+__visible void trace_hardirqs_on_caller(unsigned long caller_addr)
+{
+	if (!this_cpu_read(tracing_irq_cpu))
+		return;
+
+	trace_irq_enable_rcuidle(CALLER_ADDR0, caller_addr);
+	this_cpu_write(tracing_irq_cpu, 0);
+}
+EXPORT_SYMBOL(trace_hardirqs_on_caller);
+
+__visible void trace_hardirqs_off_caller(unsigned long caller_addr)
+{
+	if (this_cpu_read(tracing_irq_cpu))
+		return;
+
+	this_cpu_write(tracing_irq_cpu, 1);
+	trace_irq_disable_rcuidle(CALLER_ADDR0, caller_addr);
+}
+EXPORT_SYMBOL(trace_hardirqs_off_caller);
+#endif /* CONFIG_TRACE_IRQFLAGS */
+
+#ifdef CONFIG_TRACE_PREEMPT_TOGGLE
+
+void trace_preempt_on(unsigned long a0, unsigned long a1)
+{
+	trace_preempt_enable_rcuidle(a0, a1);
+}
+
+void trace_preempt_off(unsigned long a0, unsigned long a1)
+{
+	trace_preempt_disable_rcuidle(a0, a1);
+}
+#endif
-- 
2.18.0

[for-next][PATCH 17/34] tracefs: Annotate tracefs_ops with __ro_after_init

[Steven Rostedt]

From: Zubin Mithra <zsm@chromium.org>

tracefs_ops is initialized inside tracefs_create_instance_dir and not
modified after. tracefs_create_instance_dir allows for initialization
only once, and is called from create_trace_instances(marked __init),
which is called from tracer_init_tracefs(marked __init). Also, mark
tracefs_create_instance_dir as __init.

Link: http://lkml.kernel.org/r/20180725171901.4468-1-zsm@chromium.org

Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Zubin Mithra <zsm@chromium.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 fs/tracefs/inode.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index bea8ad876bf9..7098c49f3693 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -53,7 +53,7 @@ static const struct file_operations tracefs_file_operations = {
 static struct tracefs_dir_ops {
 	int (*mkdir)(const char *name);
 	int (*rmdir)(const char *name);
-} tracefs_ops;
+} tracefs_ops __ro_after_init;
 
 static char *get_dname(struct dentry *dentry)
 {
@@ -478,7 +478,8 @@ struct dentry *tracefs_create_dir(const char *name, struct dentry *parent)
  *
  * Returns the dentry of the instances directory.
  */
-struct dentry *tracefs_create_instance_dir(const char *name, struct dentry *parent,
+__init struct dentry *tracefs_create_instance_dir(const char *name,
+					  struct dentry *parent,
 					  int (*mkdir)(const char *name),
 					  int (*rmdir)(const char *name))
 {
-- 
2.18.0

[for-next][PATCH 18/34] tracing: Do not call start/stop() functions when tracing_on does not change

[Steven Rostedt]

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

Currently, when one echo's in 1 into tracing_on, the current tracer's
"start()" function is executed, even if tracing_on was already one. This can
lead to strange side effects. One being that if the hwlat tracer is enabled,
and someone does "echo 1 > tracing_on" into tracing_on, the hwlat tracer's
start() function is called again which will recreate another kernel thread,
and make it unable to remove the old one.

Link: http://lkml.kernel.org/r/1533120354-22923-1-git-send-email-erica.bugden@linutronix.de

Cc: stable@vger.kernel.org
Fixes: 2df8f8a6a897e ("tracing: Fix regression with irqsoff tracer and tracing_on file")
Reported-by: Erica Bugden <erica.bugden@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 823687997b01..2378bb4f1442 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -7628,7 +7628,9 @@ rb_simple_write(struct file *filp, const char __user *ubuf,
 
 	if (buffer) {
 		mutex_lock(&trace_types_lock);
-		if (val) {
+		if (!!val == tracer_tracing_is_on(tr)) {
+			val = 0; /* do nothing */
+		} else if (val) {
 			tracer_tracing_on(tr);
 			if (tr->current_trace->start)
 				tr->current_trace->start(tr);
-- 
2.18.0

[for-next][PATCH 19/34] ftrace: Add missing check for existing hwlat thread

[Steven Rostedt]

From: Erica Bugden <erica.bugden@linutronix.de>

The hwlat tracer uses a kernel thread to measure latencies. The function
that creates this kernel thread, start_kthread(), can be called when the
tracer is initialized and when the tracer is explicitly enabled.
start_kthread() does not check if there is an existing hwlat kernel
thread and will create a new one each time it is called.

This causes the reference to the previous thread to be lost. Without the
thread reference, the old kernel thread becomes unstoppable and
continues to use CPU time even after the hwlat tracer has been disabled.
This problem can be observed when a system is booted with tracing
enabled and the hwlat tracer is configured like this:

	echo hwlat > current_tracer; echo 1 > tracing_on

Add the missing check for an existing kernel thread in start_kthread()
to prevent this problem. This function and the rest of the hwlat kernel
thread setup and teardown are already serialized because they are called
through the tracer core code with trace_type_lock held.

[
 Note, this only fixes the symptom. The real fix was not to call
 this function when tracing_on was already one. But this still makes
 the code more robust, so we'll add it.
]

Link: http://lkml.kernel.org/r/1533120354-22923-1-git-send-email-erica.bugden@linutronix.de

Signed-off-by: Erica Bugden <erica.bugden@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_hwlat.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c
index d7c8e4ec3d9d..2d9d36dd5fe7 100644
--- a/kernel/trace/trace_hwlat.c
+++ b/kernel/trace/trace_hwlat.c
@@ -354,6 +354,9 @@ static int start_kthread(struct trace_array *tr)
 	struct task_struct *kthread;
 	int next_cpu;
 
+	if (hwlat_kthread)
+		return 0;
+
 	/* Just pick the first CPU on first iteration */
 	current_mask = &save_cpumask;
 	get_online_cpus();
-- 
2.18.0

[for-next][PATCH 20/34] tracing: Do a WARN_ON() if start_thread() in hwlat is called when thread exists

[Steven Rostedt]

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

The start function of the hwlat tracer should never be called when the hwlat
thread already exists. If it is called, do a WARN_ON().

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

diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c
index 2d9d36dd5fe7..688e48be7bb5 100644
--- a/kernel/trace/trace_hwlat.c
+++ b/kernel/trace/trace_hwlat.c
@@ -354,7 +354,7 @@ static int start_kthread(struct trace_array *tr)
 	struct task_struct *kthread;
 	int next_cpu;
 
-	if (hwlat_kthread)
+	if (WARN_ON(hwlat_kthread))
 		return 0;
 
 	/* Just pick the first CPU on first iteration */
-- 
2.18.0

[for-next][PATCH 21/34] tracing: Make tracer_tracing_is_on() return bool

[Steven Rostedt]

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

There's code that expects tracer_tracing_is_on() to be either true or false,
not some random number. Currently, it should only return one or zero, but
just in case, change its return value to bool, to enforce it.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace.c | 2 +-
 kernel/trace/trace.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 2378bb4f1442..2dad27809794 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1087,7 +1087,7 @@ void disable_trace_on_warning(void)
  *
  * Shows real state of the ring buffer if it is enabled or not.
  */
-int tracer_tracing_is_on(struct trace_array *tr)
+bool tracer_tracing_is_on(struct trace_array *tr)
 {
 	if (tr->trace_buffer.buffer)
 		return ring_buffer_record_is_on(tr->trace_buffer.buffer);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index e1c8a1d6f240..d88cd9bb72f4 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -594,7 +594,7 @@ void tracing_reset_current(int cpu);
 void tracing_reset_all_online_cpus(void);
 int tracing_open_generic(struct inode *inode, struct file *filp);
 bool tracing_is_disabled(void);
-int tracer_tracing_is_on(struct trace_array *tr);
+bool tracer_tracing_is_on(struct trace_array *tr);
 void tracer_tracing_on(struct trace_array *tr);
 void tracer_tracing_off(struct trace_array *tr);
 struct dentry *trace_create_file(const char *name,
-- 
2.18.0

[for-next][PATCH 22/34] ring-buffer: Make ring_buffer_record_is_on() return bool

[Steven Rostedt]

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

The value of ring_buffer_record_is_on() is either true or false, so have its
return value be bool.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/linux/ring_buffer.h | 2 +-
 kernel/trace/ring_buffer.c  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index 003d09ab308d..5176124fc4ba 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -164,7 +164,7 @@ void ring_buffer_record_disable(struct ring_buffer *buffer);
 void ring_buffer_record_enable(struct ring_buffer *buffer);
 void ring_buffer_record_off(struct ring_buffer *buffer);
 void ring_buffer_record_on(struct ring_buffer *buffer);
-int ring_buffer_record_is_on(struct ring_buffer *buffer);
+bool ring_buffer_record_is_on(struct ring_buffer *buffer);
 int ring_buffer_record_is_set_on(struct ring_buffer *buffer);
 void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu);
 void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu);
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 0b0b688ea166..ffb43cbc5c13 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -3221,7 +3221,7 @@ EXPORT_SYMBOL_GPL(ring_buffer_record_on);
  *
  * Returns true if the ring buffer is in a state that it accepts writes.
  */
-int ring_buffer_record_is_on(struct ring_buffer *buffer)
+bool ring_buffer_record_is_on(struct ring_buffer *buffer)
 {
 	return !atomic_read(&buffer->record_disabled);
 }
-- 
2.18.0

[for-next][PATCH 23/34] ring-buffer: Make ring_buffer_record_is_set_on() return bool

[Steven Rostedt]

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

The value of ring_buffer_record_is_set_on() is either true or false, so have
its return value be bool.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/linux/ring_buffer.h | 2 +-
 kernel/trace/ring_buffer.c  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index 5176124fc4ba..0940fda59872 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -165,7 +165,7 @@ void ring_buffer_record_enable(struct ring_buffer *buffer);
 void ring_buffer_record_off(struct ring_buffer *buffer);
 void ring_buffer_record_on(struct ring_buffer *buffer);
 bool ring_buffer_record_is_on(struct ring_buffer *buffer);
-int ring_buffer_record_is_set_on(struct ring_buffer *buffer);
+bool ring_buffer_record_is_set_on(struct ring_buffer *buffer);
 void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu);
 void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu);
 
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index ffb43cbc5c13..b386830b4d51 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -3237,7 +3237,7 @@ bool ring_buffer_record_is_on(struct ring_buffer *buffer)
  * ring_buffer_record_disable(), as that is a temporary disabling of
  * the ring buffer.
  */
-int ring_buffer_record_is_set_on(struct ring_buffer *buffer)
+bool ring_buffer_record_is_set_on(struct ring_buffer *buffer)
 {
 	return !(atomic_read(&buffer->record_disabled) & RB_BUFFER_OFF);
 }
-- 
2.18.0

[for-next][PATCH 24/34] ftrace: Use true and false for boolean values in ops_references_rec()

[Steven Rostedt]

From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>

Return statements in functions returning bool should use true or false
instead of an integer value.

This code was detected with the help of Coccinelle.

Link: http://lkml.kernel.org/r/20180802010056.GA31012@embeddedor.com

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 0d380a98a880..2d795193024b 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2898,22 +2898,22 @@ ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
 {
 	/* If ops isn't enabled, ignore it */
 	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
-		return 0;
+		return false;
 
 	/* If ops traces all then it includes this function */
 	if (ops_traces_mod(ops))
-		return 1;
+		return true;
 
 	/* The function must be in the filter */
 	if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
 	    !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
-		return 0;
+		return false;
 
 	/* If in notrace hash, we ignore it too */
 	if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
-		return 0;
+		return false;
 
-	return 1;
+	return true;
 }
 
 static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
-- 
2.18.0

[for-next][PATCH 25/34] tracing/kprobes: Fix within_notrace_func() to check only notrace functions

[Steven Rostedt]

From: Masami Hiramatsu <mhiramat@kernel.org>

Fix within_notrace_func() to check only notrace functions and to ignore the
kprobe-event which can not solve symbol addresses.

within_notrace_func() returns true if the given kprobe events probe point
seems to be out-of-range. But that is not the correct place to check for it,
it should be done in kprobes afterwards.

kprobe-events allow users to define a probe point on "currently unloaded
module" so that it can trace the event during module load. In this case, the
user will put a probe on a symbol which is not in kallsyms yet and it hits
the within_notrace_func().  As a result, kprobe-events always refuses if
user defines a probe on a "currenly unloaded module".

Fixes: commit 45408c4f9250 ("tracing: kprobes: Prohibit probing on notrace function")
Link: http://lkml.kernel.org/r/153319624799.29007.13604430345640129926.stgit@devbox

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_kprobe.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index deeb03ae21e1..2e13f77b9a37 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -88,6 +88,7 @@ static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
 	return nhit;
 }
 
+/* Return 0 if it fails to find the symbol address */
 static nokprobe_inline
 unsigned long trace_kprobe_address(struct trace_kprobe *tk)
 {
@@ -96,7 +97,8 @@ unsigned long trace_kprobe_address(struct trace_kprobe *tk)
 	if (tk->symbol) {
 		addr = (unsigned long)
 			kallsyms_lookup_name(trace_kprobe_symbol(tk));
-		addr += tk->rp.kp.offset;
+		if (addr)
+			addr += tk->rp.kp.offset;
 	} else {
 		addr = (unsigned long)tk->rp.kp.addr;
 	}
@@ -519,8 +521,8 @@ static bool within_notrace_func(struct trace_kprobe *tk)
 	unsigned long offset, size, addr;
 
 	addr = trace_kprobe_address(tk);
-	if (!kallsyms_lookup_size_offset(addr, &size, &offset))
-		return true;	/* Out of range. */
+	if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))
+		return false;
 
 	return !ftrace_location_range(addr - offset, addr - offset + size);
 }
-- 
2.18.0

[for-next][PATCH 26/34] trace: Use rcu_dereference_raw for hooks from trace-event subsystem

[Steven Rostedt]

From: "Joel Fernandes (Google)" <joel@joelfernandes.org>

Since we switched to using SRCU for tracepoints used in the idle path,
we can no longer use rcu_dereference_sched for dereferencing points in
trace-event hooks.

Since tracepoints can now use either SRCU or sched-RCU, just use
rcu_dereference_raw for traceevents just like we're doing when
dereferencing the tracepoint table.

This prevents an RCU warning reported by Masami:

[  282.060593] WARNING: can't dereference registers at 00000000f3c7f62b
[  282.063200] =============================
[  282.064082] WARNING: suspicious RCU usage
[  282.064963] 4.18.0-rc6+ #15 Tainted: G        W
[  282.066048] -----------------------------
[  282.066923] /home/mhiramat/ksrc/linux/kernel/trace/trace_events.c:242
				suspicious rcu_dereference_check() usage!
[  282.068974]
[  282.068974] other info that might help us debug this:
[  282.068974]
[  282.070770]
[  282.070770] RCU used illegally from idle CPU!
[  282.070770] rcu_scheduler_active = 2, debug_locks = 1
[  282.072938] RCU used illegally from extended quiescent state!
[  282.074183] no locks held by swapper/0/0.
[  282.075071]
[  282.075071] stack backtrace:
[  282.076121] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G        W
[  282.077782] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
[  282.079604] Call Trace:
[  282.080212]  <IRQ>
[  282.080755]  dump_stack+0x85/0xcb
[  282.081523]  trace_event_ignore_this_pid+0x66/0x70
[  282.082541]  trace_event_raw_event_preemptirq_template+0xa2/0xb0
[  282.083774]  ? interrupt_entry+0xc4/0xe0
[  282.084665]  ? trace_hardirqs_off_thunk+0x1a/0x1c
[  282.085669]  trace_hardirqs_off_caller+0x90/0xd0
[  282.086597]  trace_hardirqs_off_thunk+0x1a/0x1c
[  282.087433]  ? call_function_interrupt+0xa/0x20
[  282.088201]  interrupt_entry+0xc4/0xe0
[  282.088848]  ? call_function_interrupt+0xa/0x20
[  282.089579]  </IRQ>
[  282.090029]  ? native_safe_halt+0x2/0x10
[  282.090695]  ? default_idle+0x1f/0x160
[  282.091330]  ? default_idle_call+0x24/0x40
[  282.091997]  ? do_idle+0x210/0x250
[  282.092658]  ? cpu_startup_entry+0x6f/0x80
[  282.093338]  ? start_kernel+0x49d/0x4bd
[  282.093987]  ? secondary_startup_64+0xa5/0xb0

Link: http://lkml.kernel.org/r/20180803023407.225852-1-joel@joelfernandes.org

Reported-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Masami Hiramatsu <mhiramat@kernel.org>
Fixes: e6753f23d961 ("tracepoint: Make rcuidle tracepoint callers use SRCU")
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_events.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 14ff4ff3caab..7b508ce8ac44 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -239,7 +239,7 @@ bool trace_event_ignore_this_pid(struct trace_event_file *trace_file)
 	struct trace_array_cpu *data;
 	struct trace_pid_list *pid_list;
 
-	pid_list = rcu_dereference_sched(tr->filtered_pids);
+	pid_list = rcu_dereference_raw(tr->filtered_pids);
 	if (!pid_list)
 		return false;
 
@@ -512,7 +512,7 @@ event_filter_pid_sched_process_exit(void *data, struct task_struct *task)
 	struct trace_pid_list *pid_list;
 	struct trace_array *tr = data;
 
-	pid_list = rcu_dereference_sched(tr->filtered_pids);
+	pid_list = rcu_dereference_raw(tr->filtered_pids);
 	trace_filter_add_remove_task(pid_list, NULL, task);
 }
 
-- 
2.18.0

[for-next][PATCH 27/34] tracing: irqsoff: Account for additional preempt_disable

[Steven Rostedt]

From: "Joel Fernandes (Google)" <joel@joelfernandes.org>

Recently we tried to make the preemptirqsoff tracer to use irqsoff
tracepoint probes. However this causes issues as reported by Masami:

[2.271078] Testing tracer preemptirqsoff: .. no entries found ..FAILED!
[2.381015] WARNING: CPU: 0 PID: 1 at /home/mhiramat/ksrc/linux/kernel/
trace/trace.c:1512 run_tracer_selftest+0xf3/0x154

This is due to the tracepoint code increasing the preempt nesting count
by calling an additional preempt_disable before calling into the
preemptoff tracer which messes up the preempt_count() check in
tracer_hardirqs_off.

To fix this, make the irqsoff tracer probes balance the additional outer
preempt_disable with a preempt_enable_notrace.

The other way to fix this is to just use SRCU for all tracepoints.
However we can't do that because we can't use NMIs from RCU context.

Link: http://lkml.kernel.org/r/20180806034049.67949-1-joel@joelfernandes.org

Fixes: c3bc8fd637a9 ("tracing: Centralize preemptirq tracepoints and unify their usage")
Fixes: e6753f23d961 ("tracepoint: Make rcuidle tracepoint callers use SRCU")
Reported-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_irqsoff.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 770cd30cda40..ffbf1505d5bc 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -603,14 +603,40 @@ static void irqsoff_tracer_stop(struct trace_array *tr)
  */
 static void tracer_hardirqs_on(void *none, unsigned long a0, unsigned long a1)
 {
+	/*
+	 * Tracepoint probes are expected to be called with preempt disabled,
+	 * We don't care about being called with preempt disabled but we need
+	 * to know in the future if that changes so we can remove the next
+	 * preempt_enable.
+	 */
+	WARN_ON_ONCE(!preempt_count());
+
+	/* Tracepoint probes disable preemption atleast once, account for that */
+	preempt_enable_notrace();
+
 	if (!preempt_trace() && irq_trace())
 		stop_critical_timing(a0, a1);
+
+	preempt_disable_notrace();
 }
 
 static void tracer_hardirqs_off(void *none, unsigned long a0, unsigned long a1)
 {
+	/*
+	 * Tracepoint probes are expected to be called with preempt disabled,
+	 * We don't care about being called with preempt disabled but we need
+	 * to know in the future if that changes so we can remove the next
+	 * preempt_enable.
+	 */
+	WARN_ON_ONCE(!preempt_count());
+
+	/* Tracepoint probes disable preemption atleast once, account for that */
+	preempt_enable_notrace();
+
 	if (!preempt_trace() && irq_trace())
 		start_critical_timing(a0, a1);
+
+	preempt_disable_notrace();
 }
 
 static int irqsoff_tracer_init(struct trace_array *tr)
-- 
2.18.0

[for-next][PATCH 28/34] tracing: Partial revert of "tracing: Centralize preemptirq tracepoints and unify their usage"

[Steven Rostedt]

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

Joel Fernandes created a nice patch that cleaned up the duplicate hooks used
by lockdep and irqsoff latency tracer. It made both use tracepoints. But it
caused lockdep to trigger several false positives. We have not figured out
why yet, but removing lockdep from using the trace event hooks and just call
its helper functions directly (like it use to), makes the problem go away.

This is a partial revert of the clean up patch c3bc8fd637a9 ("tracing:
Centralize preemptirq tracepoints and unify their usage") that adds direct
calls for lockdep, but also keeps most of the clean up done to get rid of
the horrible preprocessor if statements.

Link: http://lkml.kernel.org/r/20180806155058.5ee875f4@gandalf.local.home

Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Fixes: c3bc8fd637a9 ("tracing: Centralize preemptirq tracepoints and unify their usage")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/linux/irqflags.h        |  8 ++++++--
 include/linux/lockdep.h         |  2 --
 init/main.c                     |  2 --
 kernel/locking/lockdep.c        | 14 ++-----------
 kernel/trace/trace_preemptirq.c | 36 ++++++++++++++++++---------------
 5 files changed, 28 insertions(+), 34 deletions(-)

diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h
index 50edb9cbbd26..21619c92c377 100644
--- a/include/linux/irqflags.h
+++ b/include/linux/irqflags.h
@@ -19,9 +19,13 @@
 #ifdef CONFIG_PROVE_LOCKING
   extern void trace_softirqs_on(unsigned long ip);
   extern void trace_softirqs_off(unsigned long ip);
+  extern void lockdep_hardirqs_on(unsigned long ip);
+  extern void lockdep_hardirqs_off(unsigned long ip);
 #else
-# define trace_softirqs_on(ip)	do { } while (0)
-# define trace_softirqs_off(ip)	do { } while (0)
+  static inline void trace_softirqs_on(unsigned long ip) { }
+  static inline void trace_softirqs_off(unsigned long ip) { }
+  static inline void lockdep_hardirqs_on(unsigned long ip) { }
+  static inline void lockdep_hardirqs_off(unsigned long ip) { }
 #endif
 
 #ifdef CONFIG_TRACE_IRQFLAGS
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index a8113357ceeb..b0d0b51c4d85 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -267,7 +267,6 @@ struct held_lock {
  * Initialization, self-test and debugging-output methods:
  */
 extern void lockdep_init(void);
-extern void lockdep_init_early(void);
 extern void lockdep_reset(void);
 extern void lockdep_reset_lock(struct lockdep_map *lock);
 extern void lockdep_free_key_range(void *start, unsigned long size);
@@ -408,7 +407,6 @@ static inline void lockdep_on(void)
 # define lock_set_class(l, n, k, s, i)		do { } while (0)
 # define lock_set_subclass(l, s, i)		do { } while (0)
 # define lockdep_init()				do { } while (0)
-# define lockdep_init_early()			do { } while (0)
 # define lockdep_init_map(lock, name, key, sub) \
 		do { (void)(name); (void)(key); } while (0)
 # define lockdep_set_class(lock, key)		do { (void)(key); } while (0)
diff --git a/init/main.c b/init/main.c
index 44fe43be84c1..5d42e577643a 100644
--- a/init/main.c
+++ b/init/main.c
@@ -649,8 +649,6 @@ asmlinkage __visible void __init start_kernel(void)
 	call_function_init();
 	WARN(!irqs_disabled(), "Interrupts were enabled early\n");
 
-	lockdep_init_early();
-
 	early_boot_irqs_disabled = false;
 	local_irq_enable();
 
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 03bfaeb9f4e6..e406c5fdb41e 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -2840,8 +2840,7 @@ static void __trace_hardirqs_on_caller(unsigned long ip)
 	debug_atomic_inc(hardirqs_on_events);
 }
 
-static void lockdep_hardirqs_on(void *none, unsigned long ignore,
-				unsigned long ip)
+void lockdep_hardirqs_on(unsigned long ip)
 {
 	if (unlikely(!debug_locks || current->lockdep_recursion))
 		return;
@@ -2885,8 +2884,7 @@ static void lockdep_hardirqs_on(void *none, unsigned long ignore,
 /*
  * Hardirqs were disabled:
  */
-static void lockdep_hardirqs_off(void *none, unsigned long ignore,
-				 unsigned long ip)
+void lockdep_hardirqs_off(unsigned long ip)
 {
 	struct task_struct *curr = current;
 
@@ -4315,14 +4313,6 @@ void lockdep_reset_lock(struct lockdep_map *lock)
 	raw_local_irq_restore(flags);
 }
 
-void __init lockdep_init_early(void)
-{
-#ifdef CONFIG_PROVE_LOCKING
-	register_trace_prio_irq_disable(lockdep_hardirqs_off, NULL, INT_MAX);
-	register_trace_prio_irq_enable(lockdep_hardirqs_on, NULL, INT_MIN);
-#endif
-}
-
 void __init lockdep_init(void)
 {
 	printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n");
diff --git a/kernel/trace/trace_preemptirq.c b/kernel/trace/trace_preemptirq.c
index e76b78bf258e..fa656b25f427 100644
--- a/kernel/trace/trace_preemptirq.c
+++ b/kernel/trace/trace_preemptirq.c
@@ -19,41 +19,45 @@ static DEFINE_PER_CPU(int, tracing_irq_cpu);
 
 void trace_hardirqs_on(void)
 {
-	if (!this_cpu_read(tracing_irq_cpu))
-		return;
+	if (this_cpu_read(tracing_irq_cpu)) {
+		trace_irq_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
+		this_cpu_write(tracing_irq_cpu, 0);
+	}
 
-	trace_irq_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
-	this_cpu_write(tracing_irq_cpu, 0);
+	lockdep_hardirqs_on(CALLER_ADDR0);
 }
 EXPORT_SYMBOL(trace_hardirqs_on);
 
 void trace_hardirqs_off(void)
 {
-	if (this_cpu_read(tracing_irq_cpu))
-		return;
+	if (!this_cpu_read(tracing_irq_cpu)) {
+		this_cpu_write(tracing_irq_cpu, 1);
+		trace_irq_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
+	}
 
-	this_cpu_write(tracing_irq_cpu, 1);
-	trace_irq_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
+	lockdep_hardirqs_off(CALLER_ADDR0);
 }
 EXPORT_SYMBOL(trace_hardirqs_off);
 
 __visible void trace_hardirqs_on_caller(unsigned long caller_addr)
 {
-	if (!this_cpu_read(tracing_irq_cpu))
-		return;
+	if (this_cpu_read(tracing_irq_cpu)) {
+		trace_irq_enable_rcuidle(CALLER_ADDR0, caller_addr);
+		this_cpu_write(tracing_irq_cpu, 0);
+	}
 
-	trace_irq_enable_rcuidle(CALLER_ADDR0, caller_addr);
-	this_cpu_write(tracing_irq_cpu, 0);
+	lockdep_hardirqs_on(CALLER_ADDR0);
 }
 EXPORT_SYMBOL(trace_hardirqs_on_caller);
 
 __visible void trace_hardirqs_off_caller(unsigned long caller_addr)
 {
-	if (this_cpu_read(tracing_irq_cpu))
-		return;
+	if (!this_cpu_read(tracing_irq_cpu)) {
+		this_cpu_write(tracing_irq_cpu, 1);
+		trace_irq_disable_rcuidle(CALLER_ADDR0, caller_addr);
+	}
 
-	this_cpu_write(tracing_irq_cpu, 1);
-	trace_irq_disable_rcuidle(CALLER_ADDR0, caller_addr);
+	lockdep_hardirqs_off(CALLER_ADDR0);
 }
 EXPORT_SYMBOL(trace_hardirqs_off_caller);
 #endif /* CONFIG_TRACE_IRQFLAGS */
-- 
2.18.0

[for-next][PATCH 29/34] tracing/irqsoff: Handle preempt_count for different configs

[Steven Rostedt]

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

I was hitting the following warning:

WARNING: CPU: 0 PID: 1 at kernel/trace/trace_irqsoff.c:631 tracer_hardirqs_off+0x15/0x2a

Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.18.0-rc6-test+ #13
Hardware name: MSI MS-7823/CSM-H87M-G43 (MS-7823), BIOS V1.6 02/22/2014
EIP: tracer_hardirqs_off+0x15/0x2a
Code: ff 85 c0 74 0e 8b 45 00 8b 50 04 8b 45 04 e8 35 ff ff ff 5d c3 55 64 a1 cc 37 51 c1 a9 ff ff ff 7f 89 e5 53 89 d3 89 ca 75 02 <0f> 0b e8 90 fc ff ff 85 c0 74 07 89 d8 e8 0c ff ff ff 5b 5d c3 55
EAX: 80000000 EBX: c04337f0 ECX: c04338e3 EDX: c04338e3
ESI: c04337f0 EDI: c04338e3 EBP: f2aa1d68 ESP: f2aa1d64
DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00210046
CR0: 80050033 CR2: 00000000 CR3: 01668000 CR4: 001406f0
Call Trace:
 trace_irq_disable_rcuidle+0x63/0x6c
 trace_hardirqs_off+0x26/0x30
 default_send_IPI_mask_allbutself_logical+0x31/0x93
 default_send_IPI_allbutself+0x37/0x48
 native_send_call_func_ipi+0x4d/0x6a
 smp_call_function_many+0x165/0x19d
 ? add_nops+0x34/0x34
 ? trace_hardirqs_on_caller+0x2d/0x2d
 ? add_nops+0x34/0x34
 smp_call_function+0x1f/0x23
 on_each_cpu+0x15/0x43
 ? trace_hardirqs_on_caller+0x2d/0x2d
 ? trace_hardirqs_on_caller+0x2d/0x2d
 ? trace_irq_disable_rcuidle+0x1/0x6c
 text_poke_bp+0xa0/0xc2
 ? trace_hardirqs_on_caller+0x2d/0x2d
 arch_jump_label_transform+0xa7/0xcb
 ? trace_irq_disable_rcuidle+0x5/0x6c
 __jump_label_update+0x3e/0x6d
 jump_label_update+0x7d/0x81
 static_key_slow_inc_cpuslocked+0x58/0x6d
 static_key_slow_inc+0x19/0x20
 tracepoint_probe_register_prio+0x19e/0x1d1
 ? start_critical_timings+0x1c/0x1c
 tracepoint_probe_register+0xf/0x11
 irqsoff_tracer_init+0x21/0xf2
 tracer_init+0x16/0x1a
 trace_selftest_startup_irqsoff+0x25/0xc4
 run_tracer_selftest+0xca/0x131
 register_tracer+0xd5/0x172
 ? trace_event_define_fields_preemptirq_template+0x45/0x45
 init_irqsoff_tracer+0xd/0x11
 do_one_initcall+0xab/0x1e8
 ? rcu_read_lock_sched_held+0x3d/0x44
 ? trace_initcall_level+0x52/0x86
 kernel_init_freeable+0x195/0x21a
 ? rest_init+0xb4/0xb4
 kernel_init+0xd/0xe4
 ret_from_fork+0x2e/0x38

It is due to running a CONFIG_PREEMPT_VOLUNTARY kernel, which would trigger
this warning every time:

	WARN_ON_ONCE(preempt_count());

Because on CONFIG_PREEMPT_VOLUNTARY, preempt_count() is always zero.

This warning is to make sure preempt_count is set because
tracer_hardirqs_on() does a preempt_enable_notrace() to make the
preempt_trace() work properly, as being called by a trace event, the trace
event code disables preemption, and the tracer wants to know what the
preemption was before it was called.

Instead of enabling preemption like this, just record the preempt_count,
subtract PREEMPT_DISABLE_OFFSET from it (which is zero with !CONFIG_PREEMPT
set), and pass that value to the necessary functions, which should use the
passed in parameter instead of calling preempt_count() directly.

Fixes: da5b3ebb45277 ("tracing: irqsoff: Account for additional preempt_disable")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_irqsoff.c | 66 ++++++++++++++++++++----------------
 1 file changed, 37 insertions(+), 29 deletions(-)

diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index ffbf1505d5bc..4af990e9c594 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -40,12 +40,12 @@ static int start_irqsoff_tracer(struct trace_array *tr, int graph);
 
 #ifdef CONFIG_PREEMPT_TRACER
 static inline int
-preempt_trace(void)
+preempt_trace(int pc)
 {
-	return ((trace_type & TRACER_PREEMPT_OFF) && preempt_count());
+	return ((trace_type & TRACER_PREEMPT_OFF) && pc);
 }
 #else
-# define preempt_trace() (0)
+# define preempt_trace(pc) (0)
 #endif
 
 #ifdef CONFIG_IRQSOFF_TRACER
@@ -366,7 +366,7 @@ check_critical_timing(struct trace_array *tr,
 }
 
 static inline void
-start_critical_timing(unsigned long ip, unsigned long parent_ip)
+start_critical_timing(unsigned long ip, unsigned long parent_ip, int pc)
 {
 	int cpu;
 	struct trace_array *tr = irqsoff_trace;
@@ -394,7 +394,7 @@ start_critical_timing(unsigned long ip, unsigned long parent_ip)
 
 	local_save_flags(flags);
 
-	__trace_function(tr, ip, parent_ip, flags, preempt_count());
+	__trace_function(tr, ip, parent_ip, flags, pc);
 
 	per_cpu(tracing_cpu, cpu) = 1;
 
@@ -402,7 +402,7 @@ start_critical_timing(unsigned long ip, unsigned long parent_ip)
 }
 
 static inline void
-stop_critical_timing(unsigned long ip, unsigned long parent_ip)
+stop_critical_timing(unsigned long ip, unsigned long parent_ip, int pc)
 {
 	int cpu;
 	struct trace_array *tr = irqsoff_trace;
@@ -428,7 +428,7 @@ stop_critical_timing(unsigned long ip, unsigned long parent_ip)
 	atomic_inc(&data->disabled);
 
 	local_save_flags(flags);
-	__trace_function(tr, ip, parent_ip, flags, preempt_count());
+	__trace_function(tr, ip, parent_ip, flags, pc);
 	check_critical_timing(tr, data, parent_ip ? : ip, cpu);
 	data->critical_start = 0;
 	atomic_dec(&data->disabled);
@@ -437,15 +437,19 @@ stop_critical_timing(unsigned long ip, unsigned long parent_ip)
 /* start and stop critical timings used to for stoppage (in idle) */
 void start_critical_timings(void)
 {
-	if (preempt_trace() || irq_trace())
-		start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
+	int pc = preempt_count();
+
+	if (preempt_trace(pc) || irq_trace())
+		start_critical_timing(CALLER_ADDR0, CALLER_ADDR1, pc);
 }
 EXPORT_SYMBOL_GPL(start_critical_timings);
 
 void stop_critical_timings(void)
 {
-	if (preempt_trace() || irq_trace())
-		stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
+	int pc = preempt_count();
+
+	if (preempt_trace(pc) || irq_trace())
+		stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1, pc);
 }
 EXPORT_SYMBOL_GPL(stop_critical_timings);
 
@@ -603,40 +607,40 @@ static void irqsoff_tracer_stop(struct trace_array *tr)
  */
 static void tracer_hardirqs_on(void *none, unsigned long a0, unsigned long a1)
 {
+	unsigned int pc = preempt_count();
+
 	/*
 	 * Tracepoint probes are expected to be called with preempt disabled,
 	 * We don't care about being called with preempt disabled but we need
 	 * to know in the future if that changes so we can remove the next
 	 * preempt_enable.
 	 */
-	WARN_ON_ONCE(!preempt_count());
-
-	/* Tracepoint probes disable preemption atleast once, account for that */
-	preempt_enable_notrace();
+	WARN_ON_ONCE(pc < PREEMPT_DISABLE_OFFSET);
 
-	if (!preempt_trace() && irq_trace())
-		stop_critical_timing(a0, a1);
+	/* Use PREEMPT_DISABLE_OFFSET to handle !CONFIG_PREEMPT cases */
+	pc -= PREEMPT_DISABLE_OFFSET;
 
-	preempt_disable_notrace();
+	if (!preempt_trace(pc) && irq_trace())
+		stop_critical_timing(a0, a1, pc);
 }
 
 static void tracer_hardirqs_off(void *none, unsigned long a0, unsigned long a1)
 {
+	unsigned int pc = preempt_count();
+
 	/*
 	 * Tracepoint probes are expected to be called with preempt disabled,
 	 * We don't care about being called with preempt disabled but we need
 	 * to know in the future if that changes so we can remove the next
 	 * preempt_enable.
 	 */
-	WARN_ON_ONCE(!preempt_count());
-
-	/* Tracepoint probes disable preemption atleast once, account for that */
-	preempt_enable_notrace();
+	WARN_ON_ONCE(pc < PREEMPT_DISABLE_OFFSET);
 
-	if (!preempt_trace() && irq_trace())
-		start_critical_timing(a0, a1);
+	/* Use PREEMPT_DISABLE_OFFSET to handle !CONFIG_PREEMPT cases */
+	pc -= PREEMPT_DISABLE_OFFSET;
 
-	preempt_disable_notrace();
+	if (!preempt_trace(pc) && irq_trace())
+		start_critical_timing(a0, a1, pc);
 }
 
 static int irqsoff_tracer_init(struct trace_array *tr)
@@ -679,14 +683,18 @@ static struct tracer irqsoff_tracer __read_mostly =
 #ifdef CONFIG_PREEMPT_TRACER
 static void tracer_preempt_on(void *none, unsigned long a0, unsigned long a1)
 {
-	if (preempt_trace() && !irq_trace())
-		stop_critical_timing(a0, a1);
+	int pc = preempt_count();
+
+	if (preempt_trace(pc) && !irq_trace())
+		stop_critical_timing(a0, a1, pc);
 }
 
 static void tracer_preempt_off(void *none, unsigned long a0, unsigned long a1)
 {
-	if (preempt_trace() && !irq_trace())
-		start_critical_timing(a0, a1);
+	int pc = preempt_count();
+
+	if (preempt_trace(pc) && !irq_trace())
+		start_critical_timing(a0, a1, pc);
 }
 
 static int preemptoff_tracer_init(struct trace_array *tr)
-- 
2.18.0

[for-next][PATCH 30/34] tracing: More reverting of "tracing: Centralize preemptirq tracepoints and unify their usage"

[Steven Rostedt]

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

Joel Fernandes created a nice patch that cleaned up the duplicate hooks used
by lockdep and irqsoff latency tracer. It made both use tracepoints. But the
latency tracer is triggering warnings when using tracepoints to call into
the latency tracer's routines. Mainly, they can be called from NMI context.
If that happens, then the SRCU may not work properly because on some
architectures, SRCU is not safe to be called in both NMI and non-NMI
context.

This is a partial revert of the clean up patch c3bc8fd637a9 ("tracing:
Centralize preemptirq tracepoints and unify their usage") that adds back the
direct calls into the latency tracer. It also only calls the trace events
when not in NMI.

Link: http://lkml.kernel.org/r/20180809210654.622445925@goodmis.org
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Fixes: c3bc8fd637a9 ("tracing: Centralize preemptirq tracepoints and unify their usage")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace.h            | 15 +++++++++++
 kernel/trace/trace_irqsoff.c    | 48 +++------------------------------
 kernel/trace/trace_preemptirq.c | 25 ++++++++++++-----
 3 files changed, 38 insertions(+), 50 deletions(-)

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index d88cd9bb72f4..a62b678731e3 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1827,6 +1827,21 @@ static inline int tracing_alloc_snapshot_instance(struct trace_array *tr)
 }
 #endif
 
+#ifdef CONFIG_PREEMPT_TRACER
+void tracer_preempt_on(unsigned long a0, unsigned long a1);
+void tracer_preempt_off(unsigned long a0, unsigned long a1);
+#else
+static inline void tracer_preempt_on(unsigned long a0, unsigned long a1) { }
+static inline void tracer_preempt_off(unsigned long a0, unsigned long a1) { }
+#endif
+#ifdef CONFIG_IRQSOFF_TRACER
+void tracer_hardirqs_on(unsigned long a0, unsigned long a1);
+void tracer_hardirqs_off(unsigned long a0, unsigned long a1);
+#else
+static inline void tracer_hardirqs_on(unsigned long a0, unsigned long a1) { }
+static inline void tracer_hardirqs_off(unsigned long a0, unsigned long a1) { }
+#endif
+
 extern struct trace_iterator *tracepoint_print_iter;
 
 #endif /* _LINUX_KERNEL_TRACE_H */
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 4af990e9c594..94c1ba139b3b 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -605,40 +605,18 @@ static void irqsoff_tracer_stop(struct trace_array *tr)
 /*
  * We are only interested in hardirq on/off events:
  */
-static void tracer_hardirqs_on(void *none, unsigned long a0, unsigned long a1)
+void tracer_hardirqs_on(unsigned long a0, unsigned long a1)
 {
 	unsigned int pc = preempt_count();
 
-	/*
-	 * Tracepoint probes are expected to be called with preempt disabled,
-	 * We don't care about being called with preempt disabled but we need
-	 * to know in the future if that changes so we can remove the next
-	 * preempt_enable.
-	 */
-	WARN_ON_ONCE(pc < PREEMPT_DISABLE_OFFSET);
-
-	/* Use PREEMPT_DISABLE_OFFSET to handle !CONFIG_PREEMPT cases */
-	pc -= PREEMPT_DISABLE_OFFSET;
-
 	if (!preempt_trace(pc) && irq_trace())
 		stop_critical_timing(a0, a1, pc);
 }
 
-static void tracer_hardirqs_off(void *none, unsigned long a0, unsigned long a1)
+void tracer_hardirqs_off(unsigned long a0, unsigned long a1)
 {
 	unsigned int pc = preempt_count();
 
-	/*
-	 * Tracepoint probes are expected to be called with preempt disabled,
-	 * We don't care about being called with preempt disabled but we need
-	 * to know in the future if that changes so we can remove the next
-	 * preempt_enable.
-	 */
-	WARN_ON_ONCE(pc < PREEMPT_DISABLE_OFFSET);
-
-	/* Use PREEMPT_DISABLE_OFFSET to handle !CONFIG_PREEMPT cases */
-	pc -= PREEMPT_DISABLE_OFFSET;
-
 	if (!preempt_trace(pc) && irq_trace())
 		start_critical_timing(a0, a1, pc);
 }
@@ -647,15 +625,11 @@ static int irqsoff_tracer_init(struct trace_array *tr)
 {
 	trace_type = TRACER_IRQS_OFF;
 
-	register_trace_irq_disable(tracer_hardirqs_off, NULL);
-	register_trace_irq_enable(tracer_hardirqs_on, NULL);
 	return __irqsoff_tracer_init(tr);
 }
 
 static void irqsoff_tracer_reset(struct trace_array *tr)
 {
-	unregister_trace_irq_disable(tracer_hardirqs_off, NULL);
-	unregister_trace_irq_enable(tracer_hardirqs_on, NULL);
 	__irqsoff_tracer_reset(tr);
 }
 
@@ -681,7 +655,7 @@ static struct tracer irqsoff_tracer __read_mostly =
 #endif /*  CONFIG_IRQSOFF_TRACER */
 
 #ifdef CONFIG_PREEMPT_TRACER
-static void tracer_preempt_on(void *none, unsigned long a0, unsigned long a1)
+void tracer_preempt_on(unsigned long a0, unsigned long a1)
 {
 	int pc = preempt_count();
 
@@ -689,7 +663,7 @@ static void tracer_preempt_on(void *none, unsigned long a0, unsigned long a1)
 		stop_critical_timing(a0, a1, pc);
 }
 
-static void tracer_preempt_off(void *none, unsigned long a0, unsigned long a1)
+void tracer_preempt_off(unsigned long a0, unsigned long a1)
 {
 	int pc = preempt_count();
 
@@ -701,15 +675,11 @@ static int preemptoff_tracer_init(struct trace_array *tr)
 {
 	trace_type = TRACER_PREEMPT_OFF;
 
-	register_trace_preempt_disable(tracer_preempt_off, NULL);
-	register_trace_preempt_enable(tracer_preempt_on, NULL);
 	return __irqsoff_tracer_init(tr);
 }
 
 static void preemptoff_tracer_reset(struct trace_array *tr)
 {
-	unregister_trace_preempt_disable(tracer_preempt_off, NULL);
-	unregister_trace_preempt_enable(tracer_preempt_on, NULL);
 	__irqsoff_tracer_reset(tr);
 }
 
@@ -740,21 +710,11 @@ static int preemptirqsoff_tracer_init(struct trace_array *tr)
 {
 	trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF;
 
-	register_trace_irq_disable(tracer_hardirqs_off, NULL);
-	register_trace_irq_enable(tracer_hardirqs_on, NULL);
-	register_trace_preempt_disable(tracer_preempt_off, NULL);
-	register_trace_preempt_enable(tracer_preempt_on, NULL);
-
 	return __irqsoff_tracer_init(tr);
 }
 
 static void preemptirqsoff_tracer_reset(struct trace_array *tr)
 {
-	unregister_trace_irq_disable(tracer_hardirqs_off, NULL);
-	unregister_trace_irq_enable(tracer_hardirqs_on, NULL);
-	unregister_trace_preempt_disable(tracer_preempt_off, NULL);
-	unregister_trace_preempt_enable(tracer_preempt_on, NULL);
-
 	__irqsoff_tracer_reset(tr);
 }
 
diff --git a/kernel/trace/trace_preemptirq.c b/kernel/trace/trace_preemptirq.c
index fa656b25f427..71f553cceb3c 100644
--- a/kernel/trace/trace_preemptirq.c
+++ b/kernel/trace/trace_preemptirq.c
@@ -9,6 +9,7 @@
 #include <linux/uaccess.h>
 #include <linux/module.h>
 #include <linux/ftrace.h>
+#include "trace.h"
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/preemptirq.h>
@@ -20,7 +21,9 @@ static DEFINE_PER_CPU(int, tracing_irq_cpu);
 void trace_hardirqs_on(void)
 {
 	if (this_cpu_read(tracing_irq_cpu)) {
-		trace_irq_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
+		if (!in_nmi())
+			trace_irq_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
+		tracer_hardirqs_on(CALLER_ADDR0, CALLER_ADDR1);
 		this_cpu_write(tracing_irq_cpu, 0);
 	}
 
@@ -32,7 +35,9 @@ void trace_hardirqs_off(void)
 {
 	if (!this_cpu_read(tracing_irq_cpu)) {
 		this_cpu_write(tracing_irq_cpu, 1);
-		trace_irq_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
+		tracer_hardirqs_off(CALLER_ADDR0, CALLER_ADDR1);
+		if (!in_nmi())
+			trace_irq_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
 	}
 
 	lockdep_hardirqs_off(CALLER_ADDR0);
@@ -42,7 +47,9 @@ EXPORT_SYMBOL(trace_hardirqs_off);
 __visible void trace_hardirqs_on_caller(unsigned long caller_addr)
 {
 	if (this_cpu_read(tracing_irq_cpu)) {
-		trace_irq_enable_rcuidle(CALLER_ADDR0, caller_addr);
+		if (!in_nmi())
+			trace_irq_enable_rcuidle(CALLER_ADDR0, caller_addr);
+		tracer_hardirqs_on(CALLER_ADDR0, caller_addr);
 		this_cpu_write(tracing_irq_cpu, 0);
 	}
 
@@ -54,7 +61,9 @@ __visible void trace_hardirqs_off_caller(unsigned long caller_addr)
 {
 	if (!this_cpu_read(tracing_irq_cpu)) {
 		this_cpu_write(tracing_irq_cpu, 1);
-		trace_irq_disable_rcuidle(CALLER_ADDR0, caller_addr);
+		tracer_hardirqs_off(CALLER_ADDR0, caller_addr);
+		if (!in_nmi())
+			trace_irq_disable_rcuidle(CALLER_ADDR0, caller_addr);
 	}
 
 	lockdep_hardirqs_off(CALLER_ADDR0);
@@ -66,11 +75,15 @@ EXPORT_SYMBOL(trace_hardirqs_off_caller);
 
 void trace_preempt_on(unsigned long a0, unsigned long a1)
 {
-	trace_preempt_enable_rcuidle(a0, a1);
+	if (!in_nmi())
+		trace_preempt_enable_rcuidle(a0, a1);
+	tracer_preempt_on(a0, a1);
 }
 
 void trace_preempt_off(unsigned long a0, unsigned long a1)
 {
-	trace_preempt_disable_rcuidle(a0, a1);
+	if (!in_nmi())
+		trace_preempt_disable_rcuidle(a0, a1);
+	tracer_preempt_off(a0, a1);
 }
 #endif
-- 
2.18.0

[for-next][PATCH 31/34] ftrace: Remove unused pointer ftrace_swapper_pid

[Steven Rostedt]

From: Colin Ian King <colin.king@canonical.com>

Pointer ftrace_swapper_pid is defined but is never used hence it is
redundant and can be removed. The use of this variable was removed
in commit 345ddcc882d8 ("ftrace: Have set_ftrace_pid use the bitmap
like events do").

Cleans up clang warning:
warning: 'ftrace_swapper_pid' defined but not used [-Wunused-const-variable=]

Link: http://lkml.kernel.org/r/20180809125609.13142-1-colin.king@canonical.com

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 2d795193024b..48b5b466ec7a 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1020,8 +1020,6 @@ static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
 }
 #endif /* CONFIG_FUNCTION_PROFILER */
 
-static struct pid * const ftrace_swapper_pid = &init_struct_pid;
-
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 static int ftrace_graph_active;
 #else
-- 
2.18.0

[for-next][PATCH 32/34] tracing: Fix synchronizing to event changes with tracepoint_synchronize_unregister()

[Steven Rostedt]

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

Now that some trace events can be protected by srcu_read_lock(tracepoint_srcu),
we need to make sure all locations that depend on this are also protected.
There were many places that did a synchronize_sched() thinking that it was
enough to protect againts access to trace events. This use to be the case,
but now that we use SRCU for _rcuidle() trace events, they may not be
protected by synchronize_sched(), as they may be called in paths that RCU is
not watching for preempt disable.

Fixes: e6753f23d961d ("tracepoint: Make rcuidle tracepoint callers use SRCU")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_events.c         |  8 ++++----
 kernel/trace/trace_events_filter.c  | 15 ++++++++-------
 kernel/trace/trace_events_hist.c    |  2 +-
 kernel/trace/trace_events_trigger.c |  6 ++++--
 4 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 7b508ce8ac44..808cf29febe2 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -636,7 +636,7 @@ static void __ftrace_clear_event_pids(struct trace_array *tr)
 	rcu_assign_pointer(tr->filtered_pids, NULL);
 
 	/* Wait till all users are no longer using pid filtering */
-	synchronize_sched();
+	tracepoint_synchronize_unregister();
 
 	trace_free_pid_list(pid_list);
 }
@@ -1622,7 +1622,7 @@ ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
 	}
 
 	if (filtered_pids) {
-		synchronize_sched();
+		tracepoint_synchronize_unregister();
 		trace_free_pid_list(filtered_pids);
 	} else if (pid_list) {
 		/*
@@ -3036,8 +3036,8 @@ int event_trace_del_tracer(struct trace_array *tr)
 	/* Disable any running events */
 	__ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
 
-	/* Access to events are within rcu_read_lock_sched() */
-	synchronize_sched();
+	/* Make sure no more events are being executed */
+	tracepoint_synchronize_unregister();
 
 	down_write(&trace_event_sem);
 	__trace_remove_event_dirs(tr);
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 893a206bcba4..184c7685d5ea 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -899,7 +899,8 @@ int filter_match_preds(struct event_filter *filter, void *rec)
 	if (!filter)
 		return 1;
 
-	prog = rcu_dereference_sched(filter->prog);
+	/* Protected by either SRCU(tracepoint_srcu) or preempt_disable */
+	prog = rcu_dereference_raw(filter->prog);
 	if (!prog)
 		return 1;
 
@@ -1626,10 +1627,10 @@ static int process_system_preds(struct trace_subsystem_dir *dir,
 
 	/*
 	 * The calls can still be using the old filters.
-	 * Do a synchronize_sched() to ensure all calls are
+	 * Do a synchronize_sched() and to ensure all calls are
 	 * done with them before we free them.
 	 */
-	synchronize_sched();
+	tracepoint_synchronize_unregister();
 	list_for_each_entry_safe(filter_item, tmp, &filter_list, list) {
 		__free_filter(filter_item->filter);
 		list_del(&filter_item->list);
@@ -1648,7 +1649,7 @@ static int process_system_preds(struct trace_subsystem_dir *dir,
 	kfree(filter);
 	/* If any call succeeded, we still need to sync */
 	if (!fail)
-		synchronize_sched();
+		tracepoint_synchronize_unregister();
 	list_for_each_entry_safe(filter_item, tmp, &filter_list, list) {
 		__free_filter(filter_item->filter);
 		list_del(&filter_item->list);
@@ -1790,7 +1791,7 @@ int apply_event_filter(struct trace_event_file *file, char *filter_string)
 		event_clear_filter(file);
 
 		/* Make sure the filter is not being used */
-		synchronize_sched();
+		tracepoint_synchronize_unregister();
 		__free_filter(filter);
 
 		return 0;
@@ -1817,7 +1818,7 @@ int apply_event_filter(struct trace_event_file *file, char *filter_string)
 
 		if (tmp) {
 			/* Make sure the call is done with the filter */
-			synchronize_sched();
+			tracepoint_synchronize_unregister();
 			__free_filter(tmp);
 		}
 	}
@@ -1847,7 +1848,7 @@ int apply_subsystem_event_filter(struct trace_subsystem_dir *dir,
 		filter = system->filter;
 		system->filter = NULL;
 		/* Ensure all filters are no longer used */
-		synchronize_sched();
+		tracepoint_synchronize_unregister();
 		filter_free_subsystem_filters(dir, tr);
 		__free_filter(filter);
 		goto out_unlock;
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index aae18af94c94..c522b51d9909 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -5141,7 +5141,7 @@ static void hist_clear(struct event_trigger_data *data)
 	if (data->name)
 		pause_named_trigger(data);
 
-	synchronize_sched();
+	tracepoint_synchronize_unregister();
 
 	tracing_map_clear(hist_data->map);
 
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index 58d21fd52932..750044ef15e8 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -34,7 +34,9 @@ void trigger_data_free(struct event_trigger_data *data)
 	if (data->cmd_ops->set_filter)
 		data->cmd_ops->set_filter(NULL, data, NULL);
 
-	synchronize_sched(); /* make sure current triggers exit before free */
+	/* make sure current triggers exit before free */
+	tracepoint_synchronize_unregister();
+
 	kfree(data);
 }
 
@@ -752,7 +754,7 @@ int set_trigger_filter(char *filter_str,
 
 	if (tmp) {
 		/* Make sure the call is done with the filter */
-		synchronize_sched();
+		tracepoint_synchronize_unregister();
 		free_event_filter(tmp);
 	}
 
-- 
2.18.0

[for-next][PATCH 33/34] uprobes: Use synchronize_rcu() not synchronize_sched()

[Steven Rostedt]

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

While debugging another bug, I was looking at all the synchronize*()
functions being used in kernel/trace, and noticed that trace_uprobes was
using synchronize_sched(), with a comment to synchronize with
{u,ret}_probe_trace_func(). When looking at those functions, the data is
protected with "rcu_read_lock()" and not with "rcu_read_lock_sched()". This
is using the wrong synchronize_*() function.

Link: http://lkml.kernel.org/r/20180809160553.469e1e32@gandalf.local.home

Cc: stable@vger.kernel.org
Fixes: 70ed91c6ec7f8 ("tracing/uprobes: Support ftrace_event_file base multibuffer")
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_uprobe.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index bf89a51e740d..ac02fafc9f1b 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -952,7 +952,7 @@ probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file)
 
 		list_del_rcu(&link->list);
 		/* synchronize with u{,ret}probe_trace_func */
-		synchronize_sched();
+		synchronize_rcu();
 		kfree(link);
 
 		if (!list_empty(&tu->tp.files))
-- 
2.18.0

[for-next][PATCH 34/34] tracepoints: Free early tracepoints after RCU is initialized

[Steven Rostedt]

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

When enabling trace events via the kernel command line, I hit this warning:

WARNING: CPU: 0 PID: 13 at kernel/rcu/srcutree.c:236 check_init_srcu_struct+0xe/0x61
Modules linked in:
CPU: 0 PID: 13 Comm: watchdog/0 Not tainted 4.18.0-rc6-test+ #6
Hardware name: MSI MS-7823/CSM-H87M-G43 (MS-7823), BIOS V1.6 02/22/2014
RIP: 0010:check_init_srcu_struct+0xe/0x61
Code: 48 c7 c6 ec 8a 65 b4 e8 ff 79 fe ff 48 89 df 31 f6 e8 f2 fa ff ff 5a
5b 41 5c 5d c3 0f 1f 44 00 00 83 3d 68 94 b8 01 01 75 02 <0f> 0b 48 8b 87 f0
0a 00 00 a8 03 74 45 55 48 89 e5 41 55 41 54 4c
RSP: 0000:ffff96eb9ea03e68 EFLAGS: 00010246
RAX: ffff96eb962b5b01 RBX: ffffffffb4a87420 RCX: 0000000000000001
RDX: ffffffffb3107969 RSI: ffff96eb962b5b40 RDI: ffffffffb4a87420
RBP: ffff96eb9ea03eb0 R08: ffffabbd00cd7f48 R09: 0000000000000000
R10: ffff96eb9ea03e68 R11: ffffffffb4a6eec0 R12: ffff96eb962b5b40
R13: ffff96eb9ea03ef8 R14: ffffffffb3107969 R15: ffffffffb3107948
FS:  0000000000000000(0000) GS:ffff96eb9ea00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff96eb13ab2000 CR3: 0000000192a1e001 CR4: 00000000001606f0
Call Trace:
 <IRQ>
 ? __call_srcu+0x2d/0x290
 ? rcu_process_callbacks+0x26e/0x448
 ? allocate_probes+0x2b/0x2b
 call_srcu+0x13/0x15
 rcu_free_old_probes+0x1f/0x21
 rcu_process_callbacks+0x2ed/0x448
 __do_softirq+0x172/0x336
 irq_exit+0x62/0xb2
 smp_apic_timer_interrupt+0x161/0x19e
 apic_timer_interrupt+0xf/0x20
 </IRQ>

The problem is that the enabling of trace events before RCU is set up will
cause SRCU to give this warning. To avoid this, add a list to store probes
that need to be freed till after RCU is initialized, and then free them
then.

Link: http://lkml.kernel.org/r/20180810113554.1df28050@gandalf.local.home
Link: http://lkml.kernel.org/r/20180810123517.5e9714ad@gandalf.local.home

Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Fixes: e6753f23d961d ("tracepoint: Make rcuidle tracepoint callers use SRCU")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/tracepoint.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 955148d91b74..96db841bf0fc 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -53,6 +53,9 @@ static LIST_HEAD(tracepoint_module_list);
  */
 static DEFINE_MUTEX(tracepoints_mutex);
 
+static struct rcu_head *early_probes;
+static bool ok_to_free_tracepoints;
+
 /*
  * Note about RCU :
  * It is used to delay the free of multiple probes array until a quiescent
@@ -80,11 +83,40 @@ static void rcu_free_old_probes(struct rcu_head *head)
 	call_srcu(&tracepoint_srcu, head, srcu_free_old_probes);
 }
 
+static __init int release_early_probes(void)
+{
+	struct rcu_head *tmp;
+
+	ok_to_free_tracepoints = true;
+
+	while (early_probes) {
+		tmp = early_probes;
+		early_probes = tmp->next;
+		call_rcu_sched(tmp, rcu_free_old_probes);
+	}
+
+	return 0;
+}
+
+/* SRCU is initialized at core_initcall */
+postcore_initcall(release_early_probes);
+
 static inline void release_probes(struct tracepoint_func *old)
 {
 	if (old) {
 		struct tp_probes *tp_probes = container_of(old,
 			struct tp_probes, probes[0]);
+
+		/*
+		 * We can't free probes if SRCU is not initialized yet.
+		 * Postpone the freeing till after SRCU is initialized.
+		 */
+		if (unlikely(!ok_to_free_tracepoints)) {
+			tp_probes->rcu.next = early_probes;
+			early_probes = &tp_probes->rcu;
+			return;
+		}
+
 		/*
 		 * Tracepoint probes are protected by both sched RCU and SRCU,
 		 * by calling the SRCU callback in the sched RCU callback we
-- 
2.18.0