LKML Archive on lore.kernel.org
 help / color / Atom feed
From: Michal Hocko <mhocko@kernel.org>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Dmitry Vyukov <dvyukov@google.com>,
	syzbot <syzbot+bab151e82a4e973fa325@syzkaller.appspotmail.com>,
	cgroups@vger.kernel.org, Johannes Weiner <hannes@cmpxchg.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>
Subject: Re: WARNING in try_charge
Date: Mon, 6 Aug 2018 13:09:34 +0200
Message-ID: <20180806110934.GJ19540@dhcp22.suse.cz> (raw)
In-Reply-To: <884de816-671a-44d4-a6a1-2ad7eff53715@I-love.SAKURA.ne.jp>

On Mon 06-08-18 19:47:00, Tetsuo Handa wrote:
> On 2018/08/06 19:39, Dmitry Vyukov wrote:
> > On Mon, Aug 6, 2018 at 11:48 AM, Michal Hocko <mhocko@kernel.org> wrote:
> >> Btw. running with the above diff on top might help us to ideantify
> >> whether this is a pre-mature warning or a valid one. Still useful to
> >> find out.
> 
> Since syzbot already found a syz reproducer, you can ask syzbot to test it.
> 
> > 
> > The bug report has a reproducer, so you can run it with the patch. Or
> > ask syzbot to test your patch:
> > https://github.com/google/syzkaller/blob/master/docs/syzbot.md#testing-patches
> > Which basically boils down to saying:
> > 
> > #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> > master
> 
> Excuse me, but this is linux-next only problem. Therefore,

If this really is a linux-next only problem then please retest with the
current linux-next which has dropped the and replaced the group oom
code.

> #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 4603ad75c9a9..852cd3dbdcd9 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -1388,6 +1388,8 @@ static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
>  	bool ret;
>  
>  	mutex_lock(&oom_lock);
> +	pr_info("task=%s pid=%d invoked memcg oom killer. oom_victim=%d\n",
> +			current->comm, current->pid, tsk_is_oom_victim(current));
>  	ret = out_of_memory(&oc);
>  	mutex_unlock(&oom_lock);
>  	return ret;
> 
> F.Y.I. Waiting until __mmput() completes (with timeout using OOM score feedback)
> ( https://syzkaller.appspot.com/x/patch.diff?x=101e449c400000 ) solves this race.

Which just means that something else is broken. Seriously, timout is not
going to fix anything. It merely changes the picture.

-- 
Michal Hocko
SUSE Labs

  reply index

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-04 13:33 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
2018-08-06 10:39       ` Dmitry Vyukov
2018-08-06 10:47         ` Tetsuo Handa
2018-08-06 11:09           ` Michal Hocko [this message]
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 14:58                 ` Michal Hocko
2018-08-06 15:12                   ` Tetsuo Handa
2018-08-06 14:54               ` David Howells
2018-08-06 15:04                 ` 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 19:46                           ` 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 15:07   ` Michal Hocko
2018-08-09 21:05     ` Tetsuo Handa
2018-08-09 15:34   ` Johannes Weiner

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20180806110934.GJ19540@dhcp22.suse.cz \
    --to=mhocko@kernel.org \
    --cc=cgroups@vger.kernel.org \
    --cc=dvyukov@google.com \
    --cc=hannes@cmpxchg.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=penguin-kernel@I-love.SAKURA.ne.jp \
    --cc=syzbot+bab151e82a4e973fa325@syzkaller.appspotmail.com \
    --cc=syzkaller-bugs@googlegroups.com \
    --cc=vdavydov.dev@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org linux-kernel@archiver.kernel.org
	public-inbox-index lkml


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/ public-inbox