From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f70.google.com (mail-ed1-f70.google.com [209.85.208.70]) by kanga.kvack.org (Postfix) with ESMTP id AE8666B000D for ; Mon, 6 Aug 2018 10:58:35 -0400 (EDT) Received: by mail-ed1-f70.google.com with SMTP id b25-v6so4283735eds.17 for ; Mon, 06 Aug 2018 07:58:35 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id g8-v6si968970edg.399.2018.08.06.07.58.34 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 06 Aug 2018 07:58:34 -0700 (PDT) Date: Mon, 6 Aug 2018 16:58:33 +0200 From: Michal Hocko Subject: Re: WARNING in try_charge Message-ID: <20180806145833.GA8607@dhcp22.suse.cz> References: <884de816-671a-44d4-a6a1-2ad7eff53715@I-love.SAKURA.ne.jp> <00000000000070698b0572c28ebc@google.com> <20180806113212.GK19540@dhcp22.suse.cz> <39db7dbc-fedf-a86e-3c8b-0192e83d3c8d@i-love.sakura.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <39db7dbc-fedf-a86e-3c8b-0192e83d3c8d@i-love.sakura.ne.jp> Sender: owner-linux-mm@kvack.org List-ID: To: Tetsuo Handa Cc: syzbot , 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 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