lkml.org 
[lkml]   [2012]   [Jun]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] powerpc/ftrace: Do not trace restore_interrupts()
From
Date
On Mon, 2012-06-04 at 22:27 -0400, Steven Rostedt wrote:
> As I was adding code that affects all archs, I started testing function
> tracer against PPC64 and found that it currently locks up with 3.4
> kernel. I figured it was due to tracing a function that shouldn't be, so
> I went through the following process to bisect to find the culprit:
>
> cat /debug/tracing/available_filter_functions > t
> num=`wc -l t`
> sed -ne "1,${num}p" t > t1
> let num=num+1
> sed -ne "${num},$p" t > t2
> cat t1 > /debug/tracing/set_ftrace_filter
> echo function /debug/tracing/current_tracer
> <failed? bisect t1, if not bisect t2>
>
> It finally came down to this function: restore_interrupts()
>
> I'm not sure why this locks up the system. It just seems to prevent
> scheduling from occurring. Interrupts seem to still work, as I can ping
> the box. But all user processes freeze.
>
> When restore_interrupts() is not traced, function tracing works fine.
>
> Cc: stable@kernel.org

This is what I get for cut-and-pasting from a random git commit. That
should be:

Cc: stable@vger.kernel.org

-- Steve

> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
>
> diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
> index 641da9e..64eec59 100644
> --- a/arch/powerpc/kernel/irq.c
> +++ b/arch/powerpc/kernel/irq.c
> @@ -277,7 +277,7 @@ EXPORT_SYMBOL(arch_local_irq_restore);
> * NOTE: This is called with interrupts hard disabled but not marked
> * as such in paca->irq_happened, so we need to resync this.
> */
> -void restore_interrupts(void)
> +void notrace restore_interrupts(void)
> {
> if (irqs_disabled()) {
> local_paca->irq_happened |= PACA_IRQ_HARD_DIS;
>




\
 
 \ /
  Last update: 2012-06-05 04:41    [W:0.027 / U:1.032 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site