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From: Al Viro <viro@ZenIV.linux.org.uk>
To: Jan Kara <jack@suse.cz>
Cc: Dmitry Vyukov <dvyukov@google.com>,
	syzbot
	<bot+f99f3a0db9007f4f4e32db54229a240c4fe57c15@syzkaller.appspotmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	jlayton@redhat.com, LKML <linux-kernel@vger.kernel.org>,
	linux-mm@kvack.org, npiggin@gmail.com, rgoldwyn@suse.com,
	ross.zwisler@linux.intel.com, syzkaller-bugs@googlegroups.com
Subject: Re: possible deadlock in generic_file_write_iter
Date: Mon, 6 Nov 2017 13:33:04 +0000	[thread overview]
Message-ID: <20171106133304.GS21978@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20171106131544.GB4359@quack2.suse.cz>

On Mon, Nov 06, 2017 at 02:15:44PM +0100, Jan Kara wrote:

> > Should we annotate these inodes with different lock types? Or use
> > nesting annotations?
> 
> Well, you'd need to have a completely separate set of locking classes for
> each filesystem to avoid false positives like these. And that would
> increase number of classes lockdep has to handle significantly. So I'm not
> sure it's really worth it...

Especially when you consider that backing file might be on a filesystem
that lives on another loop device.  *All* per-{device,fs} locks involved
would need classes split that way...

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  reply	other threads:[~2017-11-06 13:33 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-05 10:25 possible deadlock in generic_file_write_iter syzbot
2017-11-05 10:39 ` Dmitry Vyukov
2017-11-06  3:29 ` Al Viro
2017-11-06  6:32   ` Dmitry Vyukov
2017-11-06 13:15     ` Jan Kara
2017-11-06 13:33       ` Al Viro [this message]
2017-11-06 13:35         ` Dmitry Vyukov
2017-11-06 16:01           ` Peter Zijlstra
2017-11-06 17:36             ` Christoph Hellwig
2017-11-06 23:45               ` Matthew Wilcox
2017-11-07  0:54             ` Byungchul Park
2017-11-07  8:11               ` Peter Zijlstra
2017-11-07  8:18                 ` Dmitry Vyukov
2017-11-07  8:30                 ` Byungchul Park
2017-11-07  8:31                   ` Dmitry Vyukov
2017-11-07  8:42                     ` Byungchul Park

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