Re: d1fc031747 ("sched/wait: assert the wait_queue_head lock is .."): EIP: __wake_up_common

[Andrew Morton]

On Thu, 14 Dec 2017 08:50:15 +0800 kernel test robot <fengguang.wu@xxxxxxxxx> wrote:

> 0day kernel testing robot got the below dmesg and the first bad commit is
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> 
> commit d1fc0317472217762fa7741260ca464077b4c877
> Author:     Christoph Hellwig <hch@xxxxxx>
> AuthorDate: Wed Dec 13 11:52:12 2017 +1100
> Commit:     Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> CommitDate: Wed Dec 13 16:04:58 2017 +1100
> 
>     sched/wait: assert the wait_queue_head lock is held in __wake_up_common
>     
>     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.

I'm probably sitting on an older version.  I've dropped

epoll: use the waitqueue lock to protect ep->wq
sched/wait: assert the wait_queue_head lock is held in __wake_up_common