From: Oleg Nesterov <oleg@redhat.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: linux-mm@kvack.org,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
David Rientjes <rientjes@google.com>,
Vladimir Davydov <vdavydov@parallels.com>,
Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/10 -v4] Handle oom bypass more gracefully
Date: Tue, 14 Jun 2016 22:44:20 +0200 [thread overview]
Message-ID: <20160614204420.GA2315@redhat.com> (raw)
In-Reply-To: <20160614201740.GA617@redhat.com>
On 06/14, Oleg Nesterov wrote:
>
> So to me this additional patch looks fine,
forgot to mention, but I think it needs another change in task_will_free_mem(),
it should ignore kthreads (should not fail if we see a kthread which shares
task->mm).
And the comment you added on top of use_mm() looks misleading in any case.
"Do not use copy_from_user from this context" looks simply wrong, why else
do you need use_mm() if you are not going to do get/put_user?
"because the address space might got reclaimed behind the back by the oom_reaper"
doesn't look right too, copy_from_user() can also fail or read ZERO_PAGE() if mm
owner does munmap/madvise.
> but probably I missed something?
Yes...
Oleg.
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WARNING: multiple messages have this Message-ID (diff)
From: Oleg Nesterov <oleg@redhat.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: linux-mm@kvack.org,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
David Rientjes <rientjes@google.com>,
Vladimir Davydov <vdavydov@parallels.com>,
Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/10 -v4] Handle oom bypass more gracefully
Date: Tue, 14 Jun 2016 22:44:20 +0200 [thread overview]
Message-ID: <20160614204420.GA2315@redhat.com> (raw)
In-Reply-To: <20160614201740.GA617@redhat.com>
On 06/14, Oleg Nesterov wrote:
>
> So to me this additional patch looks fine,
forgot to mention, but I think it needs another change in task_will_free_mem(),
it should ignore kthreads (should not fail if we see a kthread which shares
task->mm).
And the comment you added on top of use_mm() looks misleading in any case.
"Do not use copy_from_user from this context" looks simply wrong, why else
do you need use_mm() if you are not going to do get/put_user?
"because the address space might got reclaimed behind the back by the oom_reaper"
doesn't look right too, copy_from_user() can also fail or read ZERO_PAGE() if mm
owner does munmap/madvise.
> but probably I missed something?
Yes...
Oleg.
next prev parent reply other threads:[~2016-06-14 20:44 UTC|newest]
Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-09 11:52 [PATCH 0/10 -v4] Handle oom bypass more gracefully Michal Hocko
2016-06-09 11:52 ` Michal Hocko
2016-06-09 11:52 ` [PATCH 01/10] proc, oom: drop bogus task_lock and mm check Michal Hocko
2016-06-09 11:52 ` Michal Hocko
2016-06-09 11:52 ` [PATCH 02/10] proc, oom: drop bogus sighand lock Michal Hocko
2016-06-09 11:52 ` Michal Hocko
2016-06-09 11:52 ` [PATCH 03/10] proc, oom_adj: extract oom_score_adj setting into a helper Michal Hocko
2016-06-09 11:52 ` Michal Hocko
2016-06-09 11:52 ` [PATCH 04/10] mm, oom_adj: make sure processes sharing mm have same view of oom_score_adj Michal Hocko
2016-06-09 11:52 ` Michal Hocko
2016-06-15 15:03 ` Oleg Nesterov
2016-06-15 15:03 ` Oleg Nesterov
2016-06-09 11:52 ` [PATCH 05/10] mm, oom: skip vforked tasks from being selected Michal Hocko
2016-06-09 11:52 ` Michal Hocko
2016-06-15 14:51 ` Oleg Nesterov
2016-06-15 14:51 ` Oleg Nesterov
2016-06-16 6:24 ` Michal Hocko
2016-06-16 6:24 ` Michal Hocko
2016-06-09 11:52 ` [PATCH 06/10] mm, oom: kill all tasks sharing the mm Michal Hocko
2016-06-09 11:52 ` Michal Hocko
2016-06-09 11:52 ` [PATCH 07/10] mm, oom: fortify task_will_free_mem Michal Hocko
2016-06-09 11:52 ` Michal Hocko
2016-06-09 13:18 ` Tetsuo Handa
2016-06-09 13:18 ` Tetsuo Handa
2016-06-09 14:20 ` Michal Hocko
2016-06-09 14:20 ` Michal Hocko
2016-06-11 8:10 ` Tetsuo Handa
2016-06-11 8:10 ` Tetsuo Handa
2016-06-13 11:27 ` Michal Hocko
2016-06-13 11:27 ` Michal Hocko
2016-06-16 12:54 ` Tetsuo Handa
2016-06-16 12:54 ` Tetsuo Handa
2016-06-16 14:29 ` Michal Hocko
2016-06-16 14:29 ` Michal Hocko
2016-06-16 15:40 ` Tetsuo Handa
2016-06-16 15:40 ` Tetsuo Handa
2016-06-16 15:53 ` Michal Hocko
2016-06-16 15:53 ` Michal Hocko
2016-06-17 11:38 ` Tetsuo Handa
2016-06-17 11:38 ` Tetsuo Handa
2016-06-17 12:26 ` Michal Hocko
2016-06-17 12:26 ` Michal Hocko
2016-06-17 13:12 ` Tetsuo Handa
2016-06-17 13:12 ` Tetsuo Handa
2016-06-17 13:29 ` Michal Hocko
2016-06-17 13:29 ` Michal Hocko
2016-06-09 11:52 ` [PATCH 08/10] mm, oom: task_will_free_mem should skip oom_reaped tasks Michal Hocko
2016-06-09 11:52 ` Michal Hocko
2016-06-17 11:35 ` Tetsuo Handa
2016-06-17 11:35 ` Tetsuo Handa
2016-06-17 12:56 ` Michal Hocko
2016-06-17 12:56 ` Michal Hocko
2016-06-09 11:52 ` [PATCH 09/10] mm, oom_reaper: do not attempt to reap a task more than twice Michal Hocko
2016-06-09 11:52 ` Michal Hocko
2016-06-15 14:48 ` Oleg Nesterov
2016-06-15 14:48 ` Oleg Nesterov
2016-06-16 6:28 ` Michal Hocko
2016-06-16 6:28 ` Michal Hocko
2016-06-09 11:52 ` [PATCH 10/10] mm, oom: hide mm which is shared with kthread or global init Michal Hocko
2016-06-09 11:52 ` Michal Hocko
2016-06-09 15:15 ` Tetsuo Handa
2016-06-09 15:15 ` Tetsuo Handa
2016-06-09 15:41 ` Michal Hocko
2016-06-09 15:41 ` Michal Hocko
2016-06-16 13:15 ` Tetsuo Handa
2016-06-16 13:15 ` Tetsuo Handa
2016-06-16 13:36 ` Tetsuo Handa
2016-06-16 13:36 ` Tetsuo Handa
2016-06-15 14:37 ` Oleg Nesterov
2016-06-15 14:37 ` Oleg Nesterov
2016-06-16 6:31 ` Michal Hocko
2016-06-16 6:31 ` Michal Hocko
2016-06-13 11:23 ` [PATCH 0/10 -v4] Handle oom bypass more gracefully Michal Hocko
2016-06-13 11:23 ` Michal Hocko
2016-06-13 14:13 ` Michal Hocko
2016-06-13 14:13 ` Michal Hocko
2016-06-14 20:17 ` Oleg Nesterov
2016-06-14 20:17 ` Oleg Nesterov
2016-06-14 20:44 ` Oleg Nesterov [this message]
2016-06-14 20:44 ` Oleg Nesterov
2016-06-16 6:33 ` Michal Hocko
2016-06-16 6:33 ` Michal Hocko
2016-06-15 15:09 ` Oleg Nesterov
2016-06-15 15:09 ` Oleg Nesterov
2016-06-16 6:34 ` Michal Hocko
2016-06-16 6:34 ` Michal Hocko
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