Re: [PATCH 1/2] workqueue: skip lockdep wq dependency in cancel_work_sync()

From: Tejun Heo
Date: Tue Aug 21 2018 - 13:27:17 EST

Hello, Johannes.

On Tue, Aug 21, 2018 at 07:18:14PM +0200, Johannes Berg wrote:
> > But this can lead to a deadlock. I'd much rather err on the side of
> > discouraging complex lock dancing around ordered workqueues, no?
> What can lead to a deadlock?

Oh not this particular case, but I was wondering whether we'd be
missing legitimate possible deadlock cases by skipping lockdep for all
cancel_work_sync()'s as they can actually flush.