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From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
To: Michal Hocko <mhocko@kernel.org>, Shakeel Butt <shakeelb@google.com>
Cc: syzbot <syzbot+d0fc9d3c166bc5e4a94b@syzkaller.appspotmail.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	"Roman Gushchin" <guro@fb.com>,
	"Johannes Weiner" <hannes@cmpxchg.org>,
	"Jérôme Glisse" <jglisse@redhat.com>,
	LKML <linux-kernel@vger.kernel.org>,
	"Linux MM" <linux-mm@kvack.org>,
	syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
	yuzhoujian@didichuxing.com
Subject: Re: general protection fault in oom_unkillable_task
Date: Mon, 17 Jun 2019 18:56:47 +0900	[thread overview]
Message-ID: <268214f9-18ef-b63e-2d4f-c344a7dd5e72@i-love.sakura.ne.jp> (raw)
In-Reply-To: <20190617063319.GB30420@dhcp22.suse.cz>

On 2019/06/17 15:33, Michal Hocko wrote:
> On Sat 15-06-19 09:11:37, Shakeel Butt wrote:
>> On Sat, Jun 15, 2019 at 6:50 AM Michal Hocko <mhocko@kernel.org> wrote:
> [...]
>>> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
>>> index 5a58778c91d4..43eb479a5dc7 100644
>>> --- a/mm/oom_kill.c
>>> +++ b/mm/oom_kill.c
>>> @@ -161,8 +161,8 @@ static bool oom_unkillable_task(struct task_struct *p,
>>>                 return true;
>>>
>>>         /* When mem_cgroup_out_of_memory() and p is not member of the group */
>>> -       if (memcg && !task_in_mem_cgroup(p, memcg))
>>> -               return true;
>>> +       if (memcg)
>>> +               return false;
>>
>> This will break the dump_tasks() usage of oom_unkillable_task(). We
>> can change dump_tasks() to traverse processes like
>> mem_cgroup_scan_tasks() for memcg OOMs.
> 
> Right you are. Doing a similar trick to the oom victim selection is
> indeed better. We should really strive to not doing a global process
> iteration when we can do a targeted scan. Care to send a patch?

I posted a patch that (as a side effect) avoids oom_unkillable_task() from dump_tasks() at
https://lore.kernel.org/linux-mm/1558519686-16057-2-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp/ .
What do you think?


  reply	other threads:[~2019-06-17  9:57 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-15  1:08 general protection fault in oom_unkillable_task syzbot
2019-06-15  1:10 ` Tetsuo Handa
2019-06-15 15:59   ` Tetsuo Handa
2019-06-15  3:15 ` Shakeel Butt
2019-06-15 13:49   ` Michal Hocko
2019-06-15 16:11     ` Shakeel Butt
2019-06-15 16:48       ` Tetsuo Handa
2019-06-15 18:50         ` Shakeel Butt
2019-06-15 21:33           ` Tetsuo Handa
2019-06-16  7:37             ` Tetsuo Handa
2019-06-16 15:13               ` Tetsuo Handa
2019-06-17  6:31                 ` Michal Hocko
2019-06-17 13:23                 ` Shakeel Butt
2019-06-18  1:45                   ` Andrew Morton
2019-06-18  4:21                     ` Shakeel Butt
2019-06-17  6:33       ` Michal Hocko
2019-06-17  9:56         ` Tetsuo Handa [this message]
2019-06-17 10:13           ` Michal Hocko
2019-06-16  5:48     ` Hillf Danton

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