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From: Andrew Morton <akpm@linux-foundation.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Ingo Molnar <mingo@redhat.com>,
	eter Zijlstra <peterz@infradead.org>,
	Al Viro <viro@zeniv.linux.org.uk>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: waitqueue lockdep annotation
Date: Thu, 30 Nov 2017 12:50:50 -0800	[thread overview]
Message-ID: <20171130125050.1faba3f06fc572846f792f17@linux-foundation.org> (raw)
In-Reply-To: <20171130142037.19339-1-hch@lst.de>

On Thu, 30 Nov 2017 06:20:35 -0800 Christoph Hellwig <hch@lst.de> wrote:

> Hi all,
> 
> this series adds a strategic lockdep_assert_held to __wake_up_common
> to ensure callers really do hold the wait_queue_head lock when calling
> the unlocked wake_up variants.  It turns out epoll did not do this
> for a fairly common path (hit all the time by systemd during bootup),
> so the second patch fixed this instance as well.

What are the runtime effects of the epoll bug?

  parent reply	other threads:[~2017-11-30 20:50 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-30 14:20 waitqueue lockdep annotation Christoph Hellwig
2017-11-30 14:20 ` [PATCH 1/2] sched/wait: assert the wait_queue_head lock is held in __wake_up_common Christoph Hellwig
2017-11-30 14:20 ` [PATCH 2/2] epoll: use proper wake_up variant in ep_poll_callback Christoph Hellwig
2017-11-30 20:50 ` Andrew Morton [this message]
2017-11-30 21:38   ` waitqueue lockdep annotation Jason Baron
2017-11-30 22:11     ` Christoph Hellwig
2017-11-30 22:18       ` Jason Baron
2017-12-01 17:11         ` Christoph Hellwig
2017-12-01 19:00           ` Jason Baron
2017-12-01 22:02             ` Christoph Hellwig
2017-12-01 22:34               ` Jason Baron
2017-12-01 23:03                 ` Christoph Hellwig
2017-12-05 15:24                   ` Jason Baron
2017-12-05 15:36                     ` Davidlohr Bueso
2017-12-06 23:51                     ` Christoph Hellwig
2017-12-06 23:52 Christoph Hellwig

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