[GIT PULL] tracing: Minor fixes

[GIT PULL] tracing: Minor fixes

[Steven Rostedt]

Linus,

This includes three minor fixes, mostly due to cut-and-paste issues.

The first is a cut and paste issue that changed the amount of stack
to skip when tracing a stack dump from 0 to 6, which basically made
the stack disappear for small stack traces.

The second fix is just removing an unused field in a struct that is no
longer used, and currently just wastes space.

The third is another cut-and-paste fix that had a tracepoint recording
the wrong field (it was recording the previous field a second time).


Please pull the latest trace-v4.5-rc1 tree, which can be found at:


  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
trace-v4.5-rc1

Tag SHA1: bec74fc4f2f54201168e16545bfd4d940cfb0ffd
Head SHA1: 7fd13615992ae0fc132c9abb24511be43f3b5d9d


Dmitry Safonov (1):
      ftrace: Remove unused nr_trampolines var

Gustavo Padovan (1):
      tracing/dma-buf/fence: Fix timeline str value on fence_annotate_wait_on

Steven Rostedt (Red Hat) (1):
      tracing: Fix stacktrace skip depth in trace_buffer_unlock_commit_regs()

----
 include/linux/ftrace.h       | 1 -
 include/trace/events/fence.h | 2 +-
 kernel/trace/trace.c         | 2 +-
 3 files changed, 2 insertions(+), 3 deletions(-)
---------------------------
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 60048c50404e..65460ad93c7b 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -164,7 +164,6 @@ struct ftrace_ops {
 	ftrace_func_t			saved_func;
 	int __percpu			*disabled;
 #ifdef CONFIG_DYNAMIC_FTRACE
-	int				nr_trampolines;
 	struct ftrace_ops_hash		local_hash;
 	struct ftrace_ops_hash		*func_hash;
 	struct ftrace_ops_hash		old_hash;
diff --git a/include/trace/events/fence.h b/include/trace/events/fence.h
index 98feb1b82896..d6dfa05ba322 100644
--- a/include/trace/events/fence.h
+++ b/include/trace/events/fence.h
@@ -17,7 +17,7 @@ TRACE_EVENT(fence_annotate_wait_on,
 
 	TP_STRUCT__entry(
 		__string(driver, fence->ops->get_driver_name(fence))
-		__string(timeline, fence->ops->get_driver_name(fence))
+		__string(timeline, fence->ops->get_timeline_name(fence))
 		__field(unsigned int, context)
 		__field(unsigned int, seqno)
 
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 87fb9801bd9e..d9293402ee68 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1751,7 +1751,7 @@ void trace_buffer_unlock_commit_regs(struct trace_array *tr,
 {
 	__buffer_unlock_commit(buffer, event);
 
-	ftrace_trace_stack(tr, buffer, flags, 6, pc, regs);
+	ftrace_trace_stack(tr, buffer, flags, 0, pc, regs);
 	ftrace_trace_userstack(buffer, flags, pc);
 }
 EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit_regs);

[GIT PULL] tracing: Minor fixes

[Steven Rostedt]

Linus,

There tracing fixes:

 - Use "nosteal" for ring buffer splice pages
 - Memory leak fix in error path of trace_pid_write()
 - Fix preempt_enable_no_resched() (use preempt_enable()) in ring buffer code


Please pull the latest trace-v5.1-rc6 tree, which can be found at:


  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
trace-v5.1-rc6

Tag SHA1: 18d3b6ef227e69c4620f9ac687bd5200ce5169bc
Head SHA1: d6097c9e4454adf1f8f2c9547c2fa6060d55d952


Jann Horn (1):
      tracing: Fix buffer_ref pipe ops

Peter Zijlstra (1):
      trace: Fix preempt_enable_no_resched() abuse

Wenwen Wang (1):
      tracing: Fix a memory leak by early error exit in trace_pid_write()

----
 fs/splice.c                |  4 ++--
 include/linux/pipe_fs_i.h  |  1 +
 kernel/trace/ring_buffer.c |  2 +-
 kernel/trace/trace.c       | 33 ++++++++++++++++++---------------
 4 files changed, 22 insertions(+), 18 deletions(-)
---------------------------
diff --git a/fs/splice.c b/fs/splice.c
index 3ee7e82df48f..e75807380caa 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -330,8 +330,8 @@ const struct pipe_buf_operations default_pipe_buf_ops = {
 	.get = generic_pipe_buf_get,
 };
 
-static int generic_pipe_buf_nosteal(struct pipe_inode_info *pipe,
-				    struct pipe_buffer *buf)
+int generic_pipe_buf_nosteal(struct pipe_inode_info *pipe,
+			     struct pipe_buffer *buf)
 {
 	return 1;
 }
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 787d224ff43e..a830e9a00eb9 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -174,6 +174,7 @@ void free_pipe_info(struct pipe_inode_info *);
 void generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *);
 int generic_pipe_buf_confirm(struct pipe_inode_info *, struct pipe_buffer *);
 int generic_pipe_buf_steal(struct pipe_inode_info *, struct pipe_buffer *);
+int generic_pipe_buf_nosteal(struct pipe_inode_info *, struct pipe_buffer *);
 void generic_pipe_buf_release(struct pipe_inode_info *, struct pipe_buffer *);
 void pipe_buf_mark_unmergeable(struct pipe_buffer *buf);
 
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 41b6f96e5366..4ee8d8aa3d0f 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -762,7 +762,7 @@ u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu)
 
 	preempt_disable_notrace();
 	time = rb_time_stamp(buffer);
-	preempt_enable_no_resched_notrace();
+	preempt_enable_notrace();
 
 	return time;
 }
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 21153e64bf1c..46f68fad6373 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -496,8 +496,10 @@ int trace_pid_write(struct trace_pid_list *filtered_pids,
 	 * not modified.
 	 */
 	pid_list = kmalloc(sizeof(*pid_list), GFP_KERNEL);
-	if (!pid_list)
+	if (!pid_list) {
+		trace_parser_put(&parser);
 		return -ENOMEM;
+	}
 
 	pid_list->pid_max = READ_ONCE(pid_max);
 
@@ -507,6 +509,7 @@ int trace_pid_write(struct trace_pid_list *filtered_pids,
 
 	pid_list->pids = vzalloc((pid_list->pid_max + 7) >> 3);
 	if (!pid_list->pids) {
+		trace_parser_put(&parser);
 		kfree(pid_list);
 		return -ENOMEM;
 	}
@@ -7025,19 +7028,23 @@ struct buffer_ref {
 	struct ring_buffer	*buffer;
 	void			*page;
 	int			cpu;
-	int			ref;
+	refcount_t		refcount;
 };
 
+static void buffer_ref_release(struct buffer_ref *ref)
+{
+	if (!refcount_dec_and_test(&ref->refcount))
+		return;
+	ring_buffer_free_read_page(ref->buffer, ref->cpu, ref->page);
+	kfree(ref);
+}
+
 static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
 				    struct pipe_buffer *buf)
 {
 	struct buffer_ref *ref = (struct buffer_ref *)buf->private;
 
-	if (--ref->ref)
-		return;
-
-	ring_buffer_free_read_page(ref->buffer, ref->cpu, ref->page);
-	kfree(ref);
+	buffer_ref_release(ref);
 	buf->private = 0;
 }
 
@@ -7046,14 +7053,14 @@ static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
 {
 	struct buffer_ref *ref = (struct buffer_ref *)buf->private;
 
-	ref->ref++;
+	refcount_inc(&ref->refcount);
 }
 
 /* Pipe buffer operations for a buffer. */
 static const struct pipe_buf_operations buffer_pipe_buf_ops = {
 	.confirm		= generic_pipe_buf_confirm,
 	.release		= buffer_pipe_buf_release,
-	.steal			= generic_pipe_buf_steal,
+	.steal			= generic_pipe_buf_nosteal,
 	.get			= buffer_pipe_buf_get,
 };
 
@@ -7066,11 +7073,7 @@ static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
 	struct buffer_ref *ref =
 		(struct buffer_ref *)spd->partial[i].private;
 
-	if (--ref->ref)
-		return;
-
-	ring_buffer_free_read_page(ref->buffer, ref->cpu, ref->page);
-	kfree(ref);
+	buffer_ref_release(ref);
 	spd->partial[i].private = 0;
 }
 
@@ -7125,7 +7128,7 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
 			break;
 		}
 
-		ref->ref = 1;
+		refcount_set(&ref->refcount, 1);
 		ref->buffer = iter->trace_buffer->buffer;
 		ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
 		if (IS_ERR(ref->page)) {

Re: [GIT PULL] tracing: Minor fixes

[pr-tracker-bot]

The pull request you sent on Fri, 26 Apr 2019 11:53:57 -0400:

> git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git trace-v5.1-rc6

has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/e9e1a2e7b486e3940badb6d743c8841ed94517b6

Thank you!

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[GIT PULL] tracing: Minor fixes

[Steven Rostedt]

Linus,

Three minor tracing fixes:

- Fix missing prototypes in sample module for direct functions

- Fix check of valid buffer in get_trace_buf()

- Fix annotations of percpu pointers.


Please pull the latest trace-v5.16-rc8 tree, which can be found at:


  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
trace-v5.16-rc8

Tag SHA1: a5f34af45294b31f67d1e62e4fcd63c130abdec1
Head SHA1: f28439db470cca8b6b082239314e9fd10bd39034


Jiri Olsa (1):
      ftrace/samples: Add missing prototypes direct functions

Naveen N. Rao (2):
      tracing: Fix check for trace_percpu_buffer validity in get_trace_buf()
      tracing: Tag trace_percpu_buffer as a percpu pointer

----
 kernel/trace/trace.c                        | 6 +++---
 samples/ftrace/ftrace-direct-modify.c       | 3 +++
 samples/ftrace/ftrace-direct-multi-modify.c | 3 +++
 samples/ftrace/ftrace-direct-too.c          | 3 +++
 samples/ftrace/ftrace-direct.c              | 2 ++
 5 files changed, 14 insertions(+), 3 deletions(-)
---------------------------
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 88de94da596b..78ea542ce3bc 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3207,7 +3207,7 @@ struct trace_buffer_struct {
 	char buffer[4][TRACE_BUF_SIZE];
 };
 
-static struct trace_buffer_struct *trace_percpu_buffer;
+static struct trace_buffer_struct __percpu *trace_percpu_buffer;
 
 /*
  * This allows for lockless recording.  If we're nested too deeply, then
@@ -3217,7 +3217,7 @@ static char *get_trace_buf(void)
 {
 	struct trace_buffer_struct *buffer =
this_cpu_ptr(trace_percpu_buffer); 
-	if (!buffer || buffer->nesting >= 4)
+	if (!trace_percpu_buffer || buffer->nesting >= 4)
 		return NULL;
 
 	buffer->nesting++;
@@ -3236,7 +3236,7 @@ static void put_trace_buf(void)
 
 static int alloc_percpu_trace_buffer(void)
 {
-	struct trace_buffer_struct *buffers;
+	struct trace_buffer_struct __percpu *buffers;
 
 	if (trace_percpu_buffer)
 		return 0;
diff --git a/samples/ftrace/ftrace-direct-modify.c
b/samples/ftrace/ftrace-direct-modify.c index 690e4a9ff333..2877cb053a82
100644 --- a/samples/ftrace/ftrace-direct-modify.c
+++ b/samples/ftrace/ftrace-direct-modify.c
@@ -4,6 +4,9 @@
 #include <linux/ftrace.h>
 #include <asm/asm-offsets.h>
 
+extern void my_direct_func1(void);
+extern void my_direct_func2(void);
+
 void my_direct_func1(void)
 {
 	trace_printk("my direct func1\n");
diff --git a/samples/ftrace/ftrace-direct-multi-modify.c
b/samples/ftrace/ftrace-direct-multi-modify.c index
91bc42a7adb9..6f43a39decd0 100644 ---
a/samples/ftrace/ftrace-direct-multi-modify.c +++
b/samples/ftrace/ftrace-direct-multi-modify.c @@ -4,6 +4,9 @@
 #include <linux/ftrace.h>
 #include <asm/asm-offsets.h>
 
+extern void my_direct_func1(unsigned long ip);
+extern void my_direct_func2(unsigned long ip);
+
 void my_direct_func1(unsigned long ip)
 {
 	trace_printk("my direct func1 ip %lx\n", ip);
diff --git a/samples/ftrace/ftrace-direct-too.c
b/samples/ftrace/ftrace-direct-too.c index 6e0de725bf22..b97e5ed46233 100644
--- a/samples/ftrace/ftrace-direct-too.c
+++ b/samples/ftrace/ftrace-direct-too.c
@@ -5,6 +5,9 @@
 #include <linux/ftrace.h>
 #include <asm/asm-offsets.h>
 
+extern void my_direct_func(struct vm_area_struct *vma,
+			   unsigned long address, unsigned int flags);
+
 void my_direct_func(struct vm_area_struct *vma,
 			unsigned long address, unsigned int flags)
 {
diff --git a/samples/ftrace/ftrace-direct.c b/samples/ftrace/ftrace-direct.c
index a30aa42ec76a..c918b13edb49 100644
--- a/samples/ftrace/ftrace-direct.c
+++ b/samples/ftrace/ftrace-direct.c
@@ -5,6 +5,8 @@
 #include <linux/ftrace.h>
 #include <asm/asm-offsets.h>
 
+extern void my_direct_func(struct task_struct *p);
+
 void my_direct_func(struct task_struct *p)
 {
 	trace_printk("waking up %s-%d\n", p->comm, p->pid);

Re: [GIT PULL] tracing: Minor fixes

[pr-tracker-bot]

The pull request you sent on Thu, 6 Jan 2022 15:58:42 -0500:

> git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git trace-v5.16-rc8

has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/b2b436ec0205abde78ef8fd438758125ffbb0fec

Thank you!

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[GIT PULL] tracing: minor fixes

[Steven Rostedt]

Linus,

Minor tracing fixes:

 - Fix unregistering the same event twice a the user could disable
   the event osnoise will disable on unregistering.

 - Inform RCU of a quiescent state in the osnoise testing thread.

 - Fix some kerneldoc comments.


Please pull the latest trace-v5.17-rc6 tree, which can be found at:


  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
trace-v5.17-rc6

Tag SHA1: c61cf6d2e56a0cd22a9d95f2006e91e895b512a2
Head SHA1: 78cbc6513217b00be6a9904415ef7ff3619eb035


Daniel Bristot de Oliveira (1):
      tracing/osnoise: Do not unregister events twice

Jiapeng Chong (1):
      ftrace: Fix some W=1 warnings in kernel doc comments

Nicolas Saenz Julienne (1):
      tracing/osnoise: Force quiescent states while tracing

----
 kernel/trace/ftrace.c        |  4 ++--
 kernel/trace/trace_osnoise.c | 31 +++++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 2 deletions(-)
---------------------------
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index a4b462b6f944..6105b7036482 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -7790,7 +7790,7 @@ int ftrace_is_dead(void)
 
 /**
  * register_ftrace_function - register a function for profiling
- * @ops - ops structure that holds the function for profiling.
+ * @ops:	ops structure that holds the function for profiling.
  *
  * Register a function to be called by all functions in the
  * kernel.
@@ -7817,7 +7817,7 @@ EXPORT_SYMBOL_GPL(register_ftrace_function);
 
 /**
  * unregister_ftrace_function - unregister a function for profiling.
- * @ops - ops structure that holds the function to unregister
+ * @ops:	ops structure that holds the function to unregister
  *
  * Unregister a function that was added to be called by ftrace profiling.
  */
diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
index cfddb30e65ab..5e3c62a08fc0 100644
--- a/kernel/trace/trace_osnoise.c
+++ b/kernel/trace/trace_osnoise.c
@@ -1386,6 +1386,26 @@ static int run_osnoise(void)
 					osnoise_stop_tracing();
 		}
 
+		/*
+		 * In some cases, notably when running on a nohz_full CPU with
+		 * a stopped tick PREEMPT_RCU has no way to account for QSs.
+		 * This will eventually cause unwarranted noise as PREEMPT_RCU
+		 * will force preemption as the means of ending the current
+		 * grace period. We avoid this problem by calling
+		 * rcu_momentary_dyntick_idle(), which performs a zero duration
+		 * EQS allowing PREEMPT_RCU to end the current grace period.
+		 * This call shouldn't be wrapped inside an RCU critical
+		 * section.
+		 *
+		 * Note that in non PREEMPT_RCU kernels QSs are handled through
+		 * cond_resched()
+		 */
+		if (IS_ENABLED(CONFIG_PREEMPT_RCU)) {
+			local_irq_disable();
+			rcu_momentary_dyntick_idle();
+			local_irq_enable();
+		}
+
 		/*
 		 * For the non-preemptive kernel config: let threads runs, if
 		 * they so wish.
@@ -2200,6 +2220,17 @@ static void osnoise_workload_stop(void)
 	if (osnoise_has_registered_instances())
 		return;
 
+	/*
+	 * If callbacks were already disabled in a previous stop
+	 * call, there is no need to disable then again.
+	 *
+	 * For instance, this happens when tracing is stopped via:
+	 * echo 0 > tracing_on
+	 * echo nop > current_tracer.
+	 */
+	if (!trace_osnoise_callback_enabled)
+		return;
+
 	trace_osnoise_callback_enabled = false;
 	/*
 	 * Make sure that ftrace_nmi_enter/exit() see

Re: [GIT PULL] tracing: minor fixes

[Linus Torvalds]

On Thu, Mar 10, 2022 at 2:45 PM Steven Rostedt <rostedt@goodmis.org> wrote:
>
>  - Fix unregistering the same event twice a the user could disable
>    the event osnoise will disable on unregistering.

What? That sounds like a (bad) markov chain text generator made random
commit noises.

I tried to edit that to something that actually makes some sense, but
who knows..

                  Linus

Re: [GIT PULL] tracing: minor fixes

[Steven Rostedt]

On Thu, 10 Mar 2022 17:28:31 -0800
Linus Torvalds <torvalds@linux-foundation.org> wrote:

> On Thu, Mar 10, 2022 at 2:45 PM Steven Rostedt <rostedt@goodmis.org> wrote:
> >
> >  - Fix unregistering the same event twice a the user could disable
> >    the event osnoise will disable on unregistering.  
> 
> What? That sounds like a (bad) markov chain text generator made random
> commit noises.
> 
> I tried to edit that to something that actually makes some sense, but
> who knows..

Ah sorry. That was something difficult to shorten, and I wrote that up at
the end of the night.

tracepoints will warn if you try to unregister a callback that is not
registered. It doesn't break anything to do so, but because tracepoints are
asynchronous, and when the user reads the ring buffer it triggers calls to
special functions associated to a tracepoint, unregistering twice usually
is because of a bug that can cause a hard to debug situation. So we warn if
a callback is unregistered from a tracepoint that is not currently
registered.

What happened above is that the osnoise tracer registered callbacks to the
tracepoints. And it unregisters them when the tracer is stopped (echo 0
into tracing_on) or removed (echo nop > current_tracer). If the user stops
osnoise with the echo 0 to tracing_on that will cause the tracepoint
callbacks to be unregistered. If the user then turns off osnoise, then it
will unregister the callbacks again, even though they were no longer
registered.

Basically it was just an accounting error.

-- Steve

Re: [GIT PULL] tracing: minor fixes

[pr-tracker-bot]

The pull request you sent on Thu, 10 Mar 2022 17:45:45 -0500:

> git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git trace-v5.17-rc6

has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/dda64ead7e82caa47fafe0edc36067ee64df2203

Thank you!

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