From: Ingo Molnar <mingo@elte.hu>
To: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Johannes Berg <johannes@sipsolutions.net>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org,
Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH 1/2] workqueue: debug flushing deadlocks with lockdep
Date: Thu, 5 Jul 2007 16:40:47 +0200 [thread overview]
Message-ID: <20070705144047.GA9548@elte.hu> (raw)
In-Reply-To: <20070705143217.GA170@tv-sign.ru>
* Oleg Nesterov <oleg@tv-sign.ru> wrote:
> Currently it is allowed that work->func() does flush_workqueue() on
> its own workqueue. So we have
>
> run_workqueue()
> work->func()
> flush_workqueue()
> run_workqueue()
>
> All but work->func() take wq->lockdep_map, I guess check_deadlock()
> won't be happy.
yep.
> OTOH. Perhaps we can can forbid such a behaviour? Andrew, do you know
> any good example of "keventd trying to flush its own queue" ?
i'd prefer to make the API a little bit stricter: such recursion is
nasty. Btw., what mechanism prevents the second instance of
run_workqueue() calling into a work->func() again?
Ingo
next prev parent reply other threads:[~2007-07-05 14:41 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-05 11:07 [PATCH 0/2] workqueue lockup debugging Johannes Berg
2007-07-05 11:07 ` [PATCH 1/2] workqueue: debug flushing deadlocks with lockdep Johannes Berg
2007-07-05 14:32 ` Oleg Nesterov
2007-07-05 14:40 ` Ingo Molnar [this message]
2007-07-05 14:52 ` Oleg Nesterov
2007-07-06 10:42 ` Johannes Berg
2007-07-05 11:07 ` [PATCH 2/2] workqueue: debug work related " Johannes Berg
2007-07-05 15:36 ` Oleg Nesterov
2007-07-06 10:43 ` Johannes Berg
2007-07-06 12:53 ` Oleg Nesterov
2007-07-11 11:37 ` Johannes Berg
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