From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-f198.google.com (mail-pg1-f198.google.com [209.85.215.198]) by kanga.kvack.org (Postfix) with ESMTP id 5D0C06B0005 for ; Mon, 6 Aug 2018 10:41:42 -0400 (EDT) Received: by mail-pg1-f198.google.com with SMTP id d12-v6so5646287pgv.12 for ; Mon, 06 Aug 2018 07:41:42 -0700 (PDT) Received: from www262.sakura.ne.jp (www262.sakura.ne.jp. [202.181.97.72]) by mx.google.com with ESMTPS id p19-v6si12500311pgm.109.2018.08.06.07.41.40 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 06 Aug 2018 07:41:41 -0700 (PDT) Subject: Re: WARNING in try_charge References: <884de816-671a-44d4-a6a1-2ad7eff53715@I-love.SAKURA.ne.jp> <00000000000070698b0572c28ebc@google.com> <20180806113212.GK19540@dhcp22.suse.cz> From: Tetsuo Handa Message-ID: <39db7dbc-fedf-a86e-3c8b-0192e83d3c8d@i-love.sakura.ne.jp> Date: Mon, 6 Aug 2018 23:41:22 +0900 MIME-Version: 1.0 In-Reply-To: <20180806113212.GK19540@dhcp22.suse.cz> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko , syzbot Cc: 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 +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. But since this problem did not occur for 3.5 hours on next-20180806 (when this problem was occurring once per 60-90 minutes), the reproducer might not be working as intended due to "kernfs, sysfs, cgroup, intel_rdt: Support fs_context" or something... ./kernel/cgroup/cgroup-internal.h | 3 ./kernel/cgroup/cgroup-v1.c | 211 ./kernel/cgroup/cgroup.c | 81