From: Johannes Weiner <hannes@cmpxchg.org>
To: Michal Hocko <mhocko@kernel.org>
Cc: Dmitry Vyukov <dvyukov@google.com>,
syzbot <syzbot+bab151e82a4e973fa325@syzkaller.appspotmail.com>,
cgroups@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Dmitry Torokhov <dtor@google.com>
Subject: Re: WARNING in try_charge
Date: Mon, 6 Aug 2018 11:31:07 -0400 [thread overview]
Message-ID: <20180806153107.GD9888@cmpxchg.org> (raw)
In-Reply-To: <20180806142124.GP19540@dhcp22.suse.cz>
On Mon, Aug 06, 2018 at 04:21:24PM +0200, Michal Hocko wrote:
> On Mon 06-08-18 13:57:38, Dmitry Vyukov wrote:
> > On Mon, Aug 6, 2018 at 1:02 PM, Michal Hocko <mhocko@kernel.org> wrote:
> > > If you have a strong reason to believe that this is an abuse of WARN I
> > > am all happy to change that. But I haven't heard any yet, to be honest.
> >
> > WARN must not be used for anything that is not kernel bugs. If this is
> > not kernel bug, WARN must not be used here.
>
> This is rather strong wording without any backing arguments. I strongly
> doubt 90% of existing WARN* match this expectation. WARN* has
> traditionally been a way to tell that something suspicious is going on.
> Those situation are mostly likely not fatal but it is good to know they
> are happening.
I have to agree with Dmitry here. WARN should indicate a real kernel
issue, not user input that knowingly triggers undesirable behavior in
the kernel. It's our assert() for states we don't think are possible.
I would wager that MOST developers and users understand it that way.
next prev parent reply other threads:[~2018-08-06 15:31 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-04 13:33 WARNING in try_charge syzbot
2018-08-04 13:45 ` Tetsuo Handa
2018-08-05 11:33 ` Tetsuo Handa
2018-08-05 8:14 ` syzbot
2018-08-06 9:15 ` Michal Hocko
2018-08-06 9:30 ` Dmitry Vyukov
2018-08-06 9:48 ` Michal Hocko
2018-08-06 10:34 ` Dmitry Vyukov
2018-08-06 11:02 ` Michal Hocko
2018-08-06 11:57 ` Dmitry Vyukov
2018-08-06 14:21 ` Michal Hocko
2018-08-06 14:58 ` Dmitry Vyukov
2018-08-06 17:30 ` Michal Hocko
2018-08-06 17:53 ` Dmitry Vyukov
2018-08-06 15:07 ` Dmitry Vyukov
2018-08-06 15:31 ` Johannes Weiner [this message]
2018-08-06 10:39 ` Dmitry Vyukov
2018-08-06 10:47 ` Tetsuo Handa
2018-08-06 11:09 ` Michal Hocko
2018-08-06 11:27 ` syzbot
2018-08-06 11:32 ` Michal Hocko
2018-08-06 11:58 ` Dmitry Vyukov
2018-08-06 14:41 ` Tetsuo Handa
2018-08-06 14:54 ` David Howells
2018-08-06 15:04 ` Tetsuo Handa
2018-08-06 14:58 ` Michal Hocko
2018-08-06 15:12 ` Tetsuo Handa
2018-08-06 11:00 ` syzbot
2018-08-06 15:32 ` Tetsuo Handa
2018-08-06 15:42 ` syzbot
2018-08-06 16:02 ` Tetsuo Handa
2018-08-06 17:44 ` Michal Hocko
2018-08-06 17:49 ` Dmitry Vyukov
2018-08-06 17:56 ` Michal Hocko
2018-08-06 18:13 ` Michal Hocko
2018-08-06 18:23 ` syzbot
2018-08-06 18:55 ` Michal Hocko
2018-08-06 19:12 ` syzbot
2018-08-06 19:45 ` Michal Hocko
2018-08-06 19:45 ` Michal Hocko
2018-08-06 19:46 ` Michal Hocko
2018-08-07 11:18 ` Dmitry Vyukov
2018-08-07 11:25 ` Michal Hocko
2018-08-06 18:39 ` Michal Hocko
2018-08-06 20:26 ` Tetsuo Handa
2018-08-06 20:34 ` Michal Hocko
2018-08-06 20:46 ` Tetsuo Handa
2018-08-06 20:55 ` Michal Hocko
2018-08-06 21:50 ` Tetsuo Handa
2018-08-07 10:19 ` Tetsuo Handa
2018-08-09 13:57 ` Tetsuo Handa
2018-08-09 13:57 ` Tetsuo Handa
2018-08-09 15:07 ` Michal Hocko
2018-08-09 21:05 ` Tetsuo Handa
2018-08-09 15:34 ` Johannes Weiner
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