From: Ingo Molnar <mingo@elte.hu>
To: Lai Jiangshan <laijs@cn.fujitsu.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Oleg Nesterov <oleg@tv-sign.ru>,
Andrew Morton <akpm@linux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] workqueue: not allow recursion run_workqueue
Date: Wed, 21 Jan 2009 11:56:31 +0100 [thread overview]
Message-ID: <20090121105631.GD25531@elte.hu> (raw)
In-Reply-To: <4976EE11.7010007@cn.fujitsu.com>
* Lai Jiangshan <laijs@cn.fujitsu.com> wrote:
> 1) lockdep will complain when recursion run_workqueue
> 2) works is not run orderly when recursion run_workqueue
>
> 3) BUG!
> We use recursion run_workqueue to hidden deadlock when
> keventd trying to flush its own queue.
>
> It's bug. When flush_workqueue()(nested in a work callback)returns,
> the workqueue is not really flushed, the sequence statement of
> this work callback will do some thing bad.
>
> So we should not allow workqueue trying to flush its own queue.
That's a nice change. I'm wondering what the existing users are though and
how difficult they are to fix.
Ingo
next prev parent reply other threads:[~2009-01-21 10:56 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-21 9:42 [PATCH] workqueue: not allow recursion run_workqueue Lai Jiangshan
2009-01-21 10:56 ` Ingo Molnar [this message]
2009-01-21 11:12 ` Peter Zijlstra
2009-01-21 12:45 ` Oleg Nesterov
2009-01-22 6:03 ` Lai Jiangshan
2009-01-22 9:52 ` Peter Zijlstra
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