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SubjectRe: [PATCH,RFC] perf: panic due to inclied cpu context task_ctx value
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On Wed, 2011-03-30 at 18:37 +0200, Oleg Nesterov wrote:
> > +static void perf_sched_events_dec(void)
> > +{
> > + jump_label_dec(&perf_sched_events_in);
> > + JUMP_LABEL(&perf_sched_events_in, no_sync);
> > + synchronize_sched();
> > +no_sync:
> > + jump_label_dec(&perf_sched_events_out);
> > +}
>
> Nice! I didn't realize we can simply use JUMP_LABEL() directly and then
> the code doesn't depend on HAVE_JUMP_LABEL.

Yeah, avoids having to sprinkle tons of #ifdef goo around ;-)

Anyway how about we do the partial revert below that should get us back
to a working kernel and is a nice small patch to send -stable wards.

After that we can try and be clever with clearing ->task_ctx from things
like remove_from_context and the like.


---
include/linux/perf_event.h | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 311b4dc..04d75a8 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1086,7 +1086,7 @@ void perf_event_task_sched_out(struct task_struct *task, struct task_struct *nex
{
perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, NULL, 0);

- COND_STMT(&perf_sched_events, __perf_event_task_sched_out(task, next));
+ __perf_event_task_sched_out(task, next);
}

extern void perf_event_mmap(struct vm_area_struct *vma);


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