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From:   Dmitry Vyukov <dvyukov@google.com>
Date:   Thu, 5 Apr 2018 10:22:07 +0200
Message-ID: <CACT4Y+bQzLe3TBvAah681Mso++swqUt7RhdFLxX5R+WKqUSgNg@mail.gmail.com>
Subject: Re: WARNING in up_write
To:     Matthew Wilcox <willy@infradead.org>
Cc:     "Theodore Y. Ts'o" <tytso@mit.edu>,
        syzbot <syzbot+dc5ab2babdf22ca091af@syzkaller.appspotmail.com>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        syzkaller-bugs@googlegroups.com, Al Viro <viro@zeniv.linux.org.uk>
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On Thu, Apr 5, 2018 at 5:24 AM, Matthew Wilcox <willy@infradead.org> 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 ;-)
>
> Date: Mon, 02 Apr 2018 19:01:01 -0700
> From: syzbot <syzbot+dc5ab2babdf22ca091af@syzkaller.appspotmail.com>
> To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
>         syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk
> Subject: WARNING in up_write

:)

#syz fix: locking/rwsem: Add up_write_non_owner() for percpu_up_write()