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Date: Thu, 30 Nov 2017 23:11:26 +0100
From: Christoph Hellwig <hch@lst.de>
To: Jason Baron <jbaron@akamai.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
        Christoph Hellwig <hch@lst.de>, Ingo Molnar <mingo@redhat.com>,
        Peter 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
Message-ID: <20171130221126.GA31795@lst.de>
References: <20171130142037.19339-1-hch@lst.de> <20171130125050.1faba3f06fc572846f792f17@linux-foundation.org> <dd769c95-3eea-93a4-9da4-cb0024461a9b@akamai.com>
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On Thu, Nov 30, 2017 at 04:38:02PM -0500, Jason Baron wrote:
> I don't think there is a bug here. The 'wake_up_locked()' calls in epoll
> are being protected by the ep->lock, not the wait_queue_head lock. So
> arguably the 'annotation' is wrong, but I don't think there is a bug
> beyond that.

They can't be protected by ep->lock.  The file might as well be
watched for using poll or select as well, or just using epoll using
another epoll fd.