[PATCH 0/2] [GIT PULL][for v2.6.32] tracing: urgent fixes

[PATCH 0/2] [GIT PULL][for v2.6.32] tracing: urgent fixes

[Steven Rostedt]

Ingo,

Please pull the latest tip/tracing/urgent tree, which can be found at:

  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git
tip/tracing/urgent


Lai Jiangshan (1):
      ring-buffer: Synchronize resizing buffer with reader lock

Li Zefan (1):
      ftrace: Fix unmatched locking in ftrace_regex_write()

----
 kernel/trace/ftrace.c      |    6 +++---
 kernel/trace/ring_buffer.c |    2 ++
 2 files changed, 5 insertions(+), 3 deletions(-)

[PATCH 1/2] [PATCH 1/2] ring-buffer: Synchronize resizing buffer with reader lock

[Steven Rostedt]

[-- Attachment #1: 0001-ring-buffer-Synchronize-resizing-buffer-with-reader-.patch --]
[-- Type: text/plain, Size: 1325 bytes --]

From: Lai Jiangshan <laijs@cn.fujitsu.com>

We got a sudden panic when we reduced the size of the
ringbuffer.

We can reproduce the panic by the following steps:

echo 1 > events/sched/enable
cat trace_pipe > /dev/null &

while ((1))
do
echo 12000 > buffer_size_kb
echo 512 > buffer_size_kb
done

(not more than 5 seconds, panic ...)

Reported-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4AF01735.9060409@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ring_buffer.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 3ffa502..5dd017f 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1193,6 +1193,7 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages)
 	atomic_inc(&cpu_buffer->record_disabled);
 	synchronize_sched();
 
+	spin_lock_irq(&cpu_buffer->reader_lock);
 	rb_head_page_deactivate(cpu_buffer);
 
 	for (i = 0; i < nr_pages; i++) {
@@ -1207,6 +1208,7 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages)
 		return;
 
 	rb_reset_cpu(cpu_buffer);
+	spin_unlock_irq(&cpu_buffer->reader_lock);
 
 	rb_check_pages(cpu_buffer);
 
-- 
1.6.3.3

[PATCH 2/2] [PATCH 2/2] ftrace: Fix unmatched locking in ftrace_regex_write()

[Steven Rostedt]

[-- Attachment #1: 0002-ftrace-Fix-unmatched-locking-in-ftrace_regex_write.patch --]
[-- Type: text/plain, Size: 1008 bytes --]

From: Li Zefan <lizf@cn.fujitsu.com>

When a command is passed to the set_ftrace_filter, then
the ftrace_regex_lock is still held going back to user space.

 # echo 'do_open : foo' > set_ftrace_filter
 (still holding ftrace_regex_lock when returning to user space!)

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4AEF7F8A.3080300@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 9c451a1..6dc4e5e 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2222,15 +2222,15 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
 		ret = ftrace_process_regex(parser->buffer,
 					   parser->idx, enable);
 		if (ret)
-			goto out;
+			goto out_unlock;
 
 		trace_parser_clear(parser);
 	}
 
 	ret = read;
-
+out_unlock:
 	mutex_unlock(&ftrace_regex_lock);
-out:
+
 	return ret;
 }
 
-- 
1.6.3.3

Re: [PATCH 0/2] [GIT PULL][for v2.6.32] tracing: urgent fixes

[Ingo Molnar]

* Steven Rostedt <rostedt@goodmis.org> wrote:

> Ingo,
> 
> Please pull the latest tip/tracing/urgent tree, which can be found at:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git
> tip/tracing/urgent
> 
> 
> Lai Jiangshan (1):
>       ring-buffer: Synchronize resizing buffer with reader lock
> 
> Li Zefan (1):
>       ftrace: Fix unmatched locking in ftrace_regex_write()
> 
> ----
>  kernel/trace/ftrace.c      |    6 +++---
>  kernel/trace/ring_buffer.c |    2 ++
>  2 files changed, 5 insertions(+), 3 deletions(-)

Pulled, thanks a lot Steve!

	Ingo