From: Tejun Heo <tj@kernel.org>
To: Thomas Tuttle <ttuttle@chromium.org>
Cc: lkml <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3] workqueue: lock cwq access in drain_workqueue
Date: Sun, 11 Sep 2011 12:30:42 +0900 [thread overview]
Message-ID: <20110911033042.GN29319@htj.dyndns.org> (raw)
In-Reply-To: <20110911032641.GA22325@google.com>
Hello,
On Sat, Sep 10, 2011 at 11:26:41PM -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>
Can you please also add "Cc: stable@kernel.org" and send it to Andrew
Morton <akpm@linux-foundation.org>?
Thank you very much.
--
tejun
next prev parent reply other threads:[~2011-09-11 3:30 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 [this message]
2011-09-11 3:39 ` Thomas Tuttle
2011-09-11 3:48 ` Tejun Heo
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