Re: [PATCH,RFC] perf: panic due to inclied cpu context task_ctx value

[Oleg Nesterov <oleg@redhat.com>]

On 03/30, Peter Zijlstra wrote:
>
> 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);
>  }

I agree completely. We need the simple (and suitable for stable) fix first.

Oleg.