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Date: Fri, 6 Apr 2018 08:32:26 +1000
From: Dave Chinner <david@fromorbit.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: "Theodore Y. Ts'o" <tytso@mit.edu>,
        Dmitry Vyukov <dvyukov@google.com>,
        syzbot <syzbot+dc5ab2babdf22ca091af@syzkaller.appspotmail.com>,
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Subject: Re: WARNING in up_write
Message-ID: <20180405223226.GA729@dastard>
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On Wed, Apr 04, 2018 at 08:24:54PM -0700, Matthew Wilcox wrote:
> On Wed, Apr 04, 2018 at 11:22:00PM -0400, Theodore Y. Ts'o wrote:
> > On Wed, Apr 04, 2018 at 12:35:04PM -0700, Matthew Wilcox wrote:
> > > On Wed, Apr 04, 2018 at 09:24:05PM +0200, Dmitry Vyukov wrote:
> > > > On Tue, Apr 3, 2018 at 4:01 AM, syzbot
> > > > <syzbot+dc5ab2babdf22ca091af@syzkaller.appspotmail.com> wrote:
> > > > > DEBUG_LOCKS_WARN_ON(sem->owner != get_current())
> > > > > WARNING: CPU: 1 PID: 4441 at kernel/locking/rwsem.c:133 up_write+0x1cc/0x210
> > > > > kernel/locking/rwsem.c:133
> > > > > Kernel panic - not syncing: panic_on_warn set ...
> > > 
> > > Message-Id: <1522852646-2196-1-git-send-email-longman@redhat.com>
> > >
> > 
> > We were way ahead of syzbot in this case.  :-)
> 
> Not really ... syzbot caught it Monday evening ;-)

Rather than arguing over who reported it first, I think that time
would be better spent reflecting on why the syzbot report was
completely ignored until *after* Ted diagnosed the issue
independently and Waiman had already fixed it....

Clearly there is scope for improvement here.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com