Re: WARNING in up_write

[Dmitry Vyukov]

On Thu, Apr 5, 2018 at 5:24 AM, Matthew Wilcox <willy@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxx>
>> >
>>
>> 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@xxxxxxxxxxxxxxxxxxxxxxxxx>
> To: linux-fsdevel@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx,
>         syzkaller-bugs@xxxxxxxxxxxxxxxx, viro@xxxxxxxxxxxxxxxxxx
> Subject: WARNING in up_write

:)

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