Messages in this thread | | | Date | Wed, 23 Aug 2017 18:39:03 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH v3 1/3] lockdep: Make LOCKDEP_CROSSRELEASE configs all part of PROVE_LOCKING |
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Peter, I am all confused and I am still trying to understand your email. In particular, because I no longer understand the lockdep annotations in workqueue.c, it turns out I forgot everything...
On 08/22, Peter Zijlstra wrote: > > I am however slightly puzzled by the need of flush_work() to take Q, > what deadlock potential is there?
Do you really mean flush_work()? Or start_flush_work() ?
> It was added by Oleg in commit: > > a67da70dc095 ("workqueues: lockdep annotations for flush_work()")
No, these annotations were moved later into start_flush, iiuc...
This
lock_map_acquire(&work->lockdep_map); lock_map_release(&work->lockdep_map);
was added by another commit 0976dfc1d0cd80a4e9dfaf87bd8744612bde475a "workqueue: Catch more locking problems with flush_work()", and at first glance it is fine.
At the same time, I have a vague feeling that (perhaps) we can remove these 2 annotations if we change process_one_work() and start_flush_work(), not sure...
Oleg.
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