From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
To: Michal Hocko <mhocko@kernel.org>
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
Subject: Re: WARNING in try_charge
Date: Tue, 7 Aug 2018 19:19:08 +0900 [thread overview]
Message-ID: <c1658a69-e6a6-6a0d-0bde-7251f81aa78d@i-love.sakura.ne.jp> (raw)
In-Reply-To: <9c03213f-c099-378b-e9fd-ed6f2a2afdc3@i-love.sakura.ne.jp>
On 2018/08/07 6:50, Tetsuo Handa wrote:
> list_for_each_entry_safe(p, tmp, &oom_victim_list, oom_victim_list) {
> struct mm_struct *mm = p->signal->oom_mm;
>
> if (oom_unkillable_task(p, oc->memcg, oc->nodemask))
> continue;
> ret = true;
> + /*
> + * Since memcg OOM allows forced charge, we can safely wait
> + * until __mmput() completes.
> + */
> + if (is_memcg_oom(oc))
> + return true;
Oops. If this OOM victim was blocked on some lock which current thread is
holding, waiting forever unconditionally is not safe.
> #ifdef CONFIG_MMU
> /*
> * Since the OOM reaper exists, we can safely wait until
> * MMF_OOM_SKIP is set.
> */
> if (!test_bit(MMF_OOM_SKIP, &mm->flags)) {
> if (!oom_reap_target) {
> get_task_struct(p);
> oom_reap_target = p;
> trace_wake_reaper(p->pid);
> wake_up(&oom_reaper_wait);
> }
> #endif
> continue;
> }
> #endif
> /* We can wait as long as OOM score is decreasing over time. */
> if (!victim_mm_stalling(p, mm))
> continue;
> gaveup = true;
> list_del(&p->oom_victim_list);
> /* Drop a reference taken by mark_oom_victim(). */
> put_task_struct(p);
> }
> if (gaveup)
> debug_show_all_locks();
>
> return ret;
> }
>
next prev parent reply other threads:[~2018-08-07 10:19 UTC|newest]
Thread overview: 53+ 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
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 14:58 ` 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 [this message]
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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