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From: Tejun Heo <tj@kernel.org>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>,
	linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org
Subject: Re: [PATCH 1/2] workqueue: skip lockdep wq dependency in cancel_work_sync()
Date: Tue, 21 Aug 2018 10:27:11 -0700	[thread overview]
Message-ID: <20180821172711.GR3978217@devbig004.ftw2.facebook.com> (raw)
In-Reply-To: <1534871894.25523.34.camel@sipsolutions.net>

Hello, Johannes.

On Tue, Aug 21, 2018 at 07:18:14PM +0200, Johannes Berg wrote:
> > But this can lead to a deadlock.  I'd much rather err on the side of
> > discouraging complex lock dancing around ordered workqueues, no?
> 
> What can lead to a deadlock?

Oh not this particular case, but I was wondering whether we'd be
missing legitimate possible deadlock cases by skipping lockdep for all
cancel_work_sync()'s as they can actually flush.

Thanks.

-- 
tejun

  reply	other threads:[~2018-08-21 17:27 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-21 12:03 [PATCH 0/2] workqueue lockdep limitations/bugs Johannes Berg
2018-08-21 12:03 ` [PATCH 1/2] workqueue: skip lockdep wq dependency in cancel_work_sync() Johannes Berg
2018-08-21 16:08   ` Tejun Heo
2018-08-21 17:18     ` Johannes Berg
2018-08-21 17:27       ` Tejun Heo [this message]
2018-08-21 17:30         ` Johannes Berg
2018-08-21 17:55           ` Tejun Heo
2018-08-21 19:20             ` Johannes Berg
2018-08-22  2:45               ` Byungchul Park
2018-08-22  4:02                 ` Johannes Berg
2018-08-22  5:47                   ` Byungchul Park
2018-08-22  7:07                     ` Johannes Berg
2018-08-22  7:50                       ` Byungchul Park
2018-08-22  8:02                         ` Johannes Berg
2018-08-22  9:15                           ` Byungchul Park
2018-08-22  9:42                             ` Johannes Berg
2018-08-22 12:47                               ` Byungchul Park
2018-08-21 12:03 ` [PATCH 2/2] workqueue: create lockdep dependency in flush_work() Johannes Berg
2018-08-21 16:09   ` Tejun Heo
2018-08-21 17:19     ` Johannes Berg
2018-08-21 16:00 ` [PATCH 0/2] workqueue lockdep limitations/bugs Tejun Heo
2018-08-21 17:15   ` Johannes Berg

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