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Date:   Mon, 6 Aug 2018 16:58:33 +0200
From:   Michal Hocko <mhocko@kernel.org>
To:     Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc:     syzbot <syzbot+bab151e82a4e973fa325@syzkaller.appspotmail.com>,
        cgroups@vger.kernel.org, dvyukov@google.com, hannes@cmpxchg.org,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        syzkaller-bugs@googlegroups.com, vdavydov.dev@gmail.com,
        David Howells <dhowells@redhat.com>
Subject: Re: WARNING in try_charge
Message-ID: <20180806145833.GA8607@dhcp22.suse.cz>
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 <20180806113212.GK19540@dhcp22.suse.cz>
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On Mon 06-08-18 23:41:22, Tetsuo Handa wrote:
> +David Howells
> 
> On 2018/08/06 20:32, Michal Hocko wrote:
> > On Mon 06-08-18 04:27:02, syzbot wrote:
> >> Hello,
> >>
> >> syzbot has tested the proposed patch and the reproducer did not trigger
> >> crash:
> >>
> >> Reported-and-tested-by:
> >> syzbot+bab151e82a4e973fa325@syzkaller.appspotmail.com
> >>
> >> Tested on:
> >>
> >> commit:         8c8399e0a3fb Add linux-next specific files for 20180806
> >> git tree:       linux-next
> >> kernel config:  https://syzkaller.appspot.com/x/.config?x=1b6bc1781e49e93e
> >> compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
> >> patch:          https://syzkaller.appspot.com/x/patch.diff?x=14fe18e2400000
> >>
> >> Note: testing is done by a robot and is best-effort only.
> > 
> > OK, so this smells like a problem in the previous group oom changes. Or
> > maybe it is not very easy to reproduce?
> > 
> 
> Since I can't find mm related changes between next-20180803 (syzbot can reproduce) and
> next-20180806 (syzbot has not reproduced), I can't guess what makes this problem go away.

Hmm, but original report was against 4.18.0-rc6-next-20180725+ kernel.
And that one had the old group oom code. /me confused.
-- 
Michal Hocko
SUSE Labs