From: Tejun Heo <tj@kernel.org>
To: Thomas Tuttle <ttuttle@chromium.org>
Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
stable@kernel.org
Subject: Re: [PATCH v3] workqueue: lock cwq access in drain_workqueue
Date: Sun, 11 Sep 2011 12:48:51 +0900 [thread overview]
Message-ID: <20110911034851.GA6428@mtj.dyndns.org> (raw)
In-Reply-To: <20110911033953.GA23049@google.com>
On Sat, Sep 10, 2011 at 11:39:53PM -0400, Thomas Tuttle wrote:
> Take cwq->gcwq->lock to avoid racing between drain_workqueue checking
> to make sure the workqueues are empty and cwq_dec_nr_in_flight
> decrementing and then incrementing nr_active when it activates a
> delayed work.
>
> We discovered this when a corner case in one of our drivers resulted in
> us trying to destroy a workqueue in which the remaining work would
> always requeue itself again in the same workqueue. We would hit this
> race condition and trip the BUG_ON on workqueue.c:3080.
>
> Signed-off-by: Thomas Tuttle <ttuttle@chromium.org>
> Acked-by: Tejun Heo <tj@kernel.org>
> Cc: stable@kernel.org
Andrew, can you please route this patch through -mm? korg is still
down and wq is unlikely to receive many more patches in this cycle.
Thank you.
--
tejun
prev parent reply other threads:[~2011-09-11 3:48 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-09 15:22 [PATCH] " Thomas Tuttle
2011-09-09 23:00 ` [PATCH v2] " Thomas Tuttle
2011-09-11 1:35 ` Tejun Heo
2011-09-11 3:26 ` [PATCH v3] " Thomas Tuttle
2011-09-11 3:30 ` Tejun Heo
2011-09-11 3:39 ` Thomas Tuttle
2011-09-11 3:48 ` Tejun Heo [this message]
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