Re: [PATCH 1/1] ptrace: task_clear_jobctl_trapping()->wake_up_bit() needs mb()

[Peter Zijlstra]

On Fri, May 16, 2014 at 03:51:37PM +0200, Oleg Nesterov wrote:
> __wake_up_bit() checks waitqueue_active() and thus the caller needs
> mb() as wake_up_bit() documents, fix task_clear_jobctl_trapping().
> 
> Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>

Seeing how you are one of the ptrace maintainers, how do you want this
routed? Does Andrew pick this up, do I stuff it somewhere?

> ---
>  kernel/signal.c |    1 +
>  1 files changed, 1 insertions(+), 0 deletions(-)
> 
> diff --git a/kernel/signal.c b/kernel/signal.c
> index c2a8542..f4c4119 100644
> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -277,6 +277,7 @@ void task_clear_jobctl_trapping(struct task_struct *task)
>  {
>  	if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
>  		task->jobctl &= ~JOBCTL_TRAPPING;
> +		smp_mb();	/* advised by wake_up_bit() */
>  		wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
>  	}
>  }
> -- 
> 1.5.5.1
> 
>

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