* [PATCH] tracing/function-return-tracer: Add a barrier to ensure return stack index is incremented in memory
@ 2008-11-15 1:37 Frederic Weisbecker
2008-11-15 1:48 ` Steven Rostedt
2008-11-16 6:43 ` Ingo Molnar
0 siblings, 2 replies; 3+ messages in thread
From: Frederic Weisbecker @ 2008-11-15 1:37 UTC (permalink / raw)
To: Ingo Molnar; +Cc: Linux Kernel, Steven Rostedt, Andi Kleen
Impact: Fix possible race condition in ftrace function return tracer
This fixes a possible race condition if index incrementation
is not immediately flushed in memory.
Thanks for Andi Kleen and Steven Rostedt for pointing out this issue
and give me this solution.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andi Kleen <andi@firstfloor.org>
---
arch/x86/kernel/ftrace.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index fe83273..db25236 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -56,6 +56,7 @@ static int push_return_trace(unsigned long ret, unsigned long long time,
return -EBUSY;
index = ++ti->curr_ret_stack;
+ barrier();
ti->ret_stack[index].ret = ret;
ti->ret_stack[index].func = func;
ti->ret_stack[index].calltime = time;
--
1.5.2.5
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] tracing/function-return-tracer: Add a barrier to ensure return stack index is incremented in memory
2008-11-15 1:37 [PATCH] tracing/function-return-tracer: Add a barrier to ensure return stack index is incremented in memory Frederic Weisbecker
@ 2008-11-15 1:48 ` Steven Rostedt
2008-11-16 6:43 ` Ingo Molnar
1 sibling, 0 replies; 3+ messages in thread
From: Steven Rostedt @ 2008-11-15 1:48 UTC (permalink / raw)
To: Frederic Weisbecker; +Cc: Ingo Molnar, Linux Kernel, Andi Kleen
On Sat, 15 Nov 2008, Frederic Weisbecker wrote:
> Impact: Fix possible race condition in ftrace function return tracer
>
> This fixes a possible race condition if index incrementation
> is not immediately flushed in memory.
>
> Thanks for Andi Kleen and Steven Rostedt for pointing out this issue
> and give me this solution.
>
> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
> Cc: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
-- Steve
> Cc: Andi Kleen <andi@firstfloor.org>
> ---
> arch/x86/kernel/ftrace.c | 1 +
> 1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
> index fe83273..db25236 100644
> --- a/arch/x86/kernel/ftrace.c
> +++ b/arch/x86/kernel/ftrace.c
> @@ -56,6 +56,7 @@ static int push_return_trace(unsigned long ret, unsigned long long time,
> return -EBUSY;
>
> index = ++ti->curr_ret_stack;
> + barrier();
> ti->ret_stack[index].ret = ret;
> ti->ret_stack[index].func = func;
> ti->ret_stack[index].calltime = time;
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] tracing/function-return-tracer: Add a barrier to ensure return stack index is incremented in memory
2008-11-15 1:37 [PATCH] tracing/function-return-tracer: Add a barrier to ensure return stack index is incremented in memory Frederic Weisbecker
2008-11-15 1:48 ` Steven Rostedt
@ 2008-11-16 6:43 ` Ingo Molnar
1 sibling, 0 replies; 3+ messages in thread
From: Ingo Molnar @ 2008-11-16 6:43 UTC (permalink / raw)
To: Frederic Weisbecker; +Cc: Linux Kernel, Steven Rostedt, Andi Kleen
* Frederic Weisbecker <fweisbec@gmail.com> wrote:
> Impact: Fix possible race condition in ftrace function return tracer
>
> This fixes a possible race condition if index incrementation
> is not immediately flushed in memory.
>
> Thanks for Andi Kleen and Steven Rostedt for pointing out this issue
> and give me this solution.
>
> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
> Cc: Steven Rostedt <rostedt@goodmis.org>
applied, thanks Frederic!
Ingo
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2008-11-16 6:43 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2008-11-15 1:37 [PATCH] tracing/function-return-tracer: Add a barrier to ensure return stack index is incremented in memory Frederic Weisbecker
2008-11-15 1:48 ` Steven Rostedt
2008-11-16 6:43 ` Ingo Molnar
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