Re: [PATCH 2/2] sched/wait: assert the wait_queue_head lock is held in __wake_up_common

[Ingo Molnar]

* Christoph Hellwig <hch@xxxxxx> wrote:

> Better ensure we actually hold the lock using lockdep than just commenting
> on it.  Due to the various exported _locked interfaces it is far too easy
> to get the locking wrong.
> 
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
>  kernel/sched/wait.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c
> index 98feab7933c7..347c06c8222e 100644
> --- a/kernel/sched/wait.c
> +++ b/kernel/sched/wait.c
> @@ -76,6 +76,8 @@ static int __wake_up_common(struct wait_queue_head *wq_head, unsigned int mode,
>  	wait_queue_entry_t *curr, *next;
>  	int cnt = 0;
>  
> +	lockdep_assert_held(&wq_head->lock);
> +
>  	if (bookmark && (bookmark->flags & WQ_FLAG_BOOKMARK)) {
>  		curr = list_next_entry(bookmark, entry);

Makes sense. Would you like to carry this patch together with the epoll patch, to 
be able to test them both? If yes then:

  Acked-by: Ingo Molnar <mingo@xxxxxxxxxx>

... otherwise I can pick this up into the scheduler tree as well.

Thanks,

	Ingo