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Subject: Re: single-threaded wq lockdep is broken
From: Johannes Berg <johannes@sipsolutions.net>
To: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Tejun Heo <tj@kernel.org>, linux-kernel <linux-kernel@vger.kernel.org>
Date: Fri, 02 Jun 2017 10:51:48 +0200
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On Fri, 2017-06-02 at 15:03 +0800, Lai Jiangshan wrote:
> 
> the @w2 is not queued before flush_work(&w2), it is expected
> that @w2 is not associated with @wq, and the dependence
> mtx -> wq will not be recorded. And it is expected no warning.

Lockdep is symmetric. So then maybe it won't warn when executing
flush_work(), but should later when executing @w2. No real difference?

johannes