From: Oleg Nesterov <oleg@redhat.com>
To: Kyle Walker <kwalker@redhat.com>,
Christoph Lameter <cl@linux.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Michal Hocko <mhocko@kernel.org>
Cc: akpm@linux-foundation.org, rientjes@google.com,
hannes@cmpxchg.org, vdavydov@parallels.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org,
Stanislav Kozina <skozina@redhat.com>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Subject: Re: can't oom-kill zap the victim's memory?
Date: Sat, 19 Sep 2015 17:10:06 +0200 [thread overview]
Message-ID: <20150919151006.GC31952@redhat.com> (raw)
In-Reply-To: <20150919150316.GB31952@redhat.com>
(off-topic)
On 09/19, Oleg Nesterov wrote:
>
> @@ -570,8 +590,8 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
> victim = p;
> }
>
> - /* mm cannot safely be dereferenced after task_unlock(victim) */
> mm = victim->mm;
> + atomic_inc(&mm->mm_count);
Btw, I think we need this change anyway. This is pure theoretical, but
otherwise this task can exit and free its mm_struct right after task_unlock(),
then this mm_struct can be reallocated and used by another task, so we
can't trust the "p->mm == mm" check below.
Oleg.
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WARNING: multiple messages have this Message-ID (diff)
From: Oleg Nesterov <oleg@redhat.com>
To: Kyle Walker <kwalker@redhat.com>,
Christoph Lameter <cl@linux.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Michal Hocko <mhocko@kernel.org>
Cc: akpm@linux-foundation.org, rientjes@google.com,
hannes@cmpxchg.org, vdavydov@parallels.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org,
Stanislav Kozina <skozina@redhat.com>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Subject: Re: can't oom-kill zap the victim's memory?
Date: Sat, 19 Sep 2015 17:10:06 +0200 [thread overview]
Message-ID: <20150919151006.GC31952@redhat.com> (raw)
In-Reply-To: <20150919150316.GB31952@redhat.com>
(off-topic)
On 09/19, Oleg Nesterov wrote:
>
> @@ -570,8 +590,8 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
> victim = p;
> }
>
> - /* mm cannot safely be dereferenced after task_unlock(victim) */
> mm = victim->mm;
> + atomic_inc(&mm->mm_count);
Btw, I think we need this change anyway. This is pure theoretical, but
otherwise this task can exit and free its mm_struct right after task_unlock(),
then this mm_struct can be reallocated and used by another task, so we
can't trust the "p->mm == mm" check below.
Oleg.
next prev parent reply other threads:[~2015-09-19 15:13 UTC|newest]
Thread overview: 213+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-17 17:59 [PATCH] mm/oom_kill.c: don't kill TASK_UNINTERRUPTIBLE tasks Kyle Walker
2015-09-17 17:59 ` Kyle Walker
2015-09-17 19:22 ` Oleg Nesterov
2015-09-17 19:22 ` Oleg Nesterov
2015-09-18 15:41 ` Christoph Lameter
2015-09-18 15:41 ` Christoph Lameter
2015-09-18 16:24 ` Oleg Nesterov
2015-09-18 16:24 ` Oleg Nesterov
2015-09-18 16:39 ` Tetsuo Handa
2015-09-18 16:39 ` Tetsuo Handa
2015-09-18 16:54 ` Oleg Nesterov
2015-09-18 16:54 ` Oleg Nesterov
2015-09-18 17:00 ` Christoph Lameter
2015-09-18 17:00 ` Christoph Lameter
2015-09-18 19:07 ` Oleg Nesterov
2015-09-18 19:07 ` Oleg Nesterov
2015-09-18 19:19 ` Christoph Lameter
2015-09-18 19:19 ` Christoph Lameter
2015-09-18 21:28 ` Kyle Walker
2015-09-18 22:07 ` Christoph Lameter
2015-09-18 22:07 ` Christoph Lameter
2015-09-19 8:32 ` Michal Hocko
2015-09-19 8:32 ` Michal Hocko
2015-09-19 14:33 ` Tetsuo Handa
2015-09-19 14:33 ` Tetsuo Handa
2015-09-19 15:51 ` Michal Hocko
2015-09-19 15:51 ` Michal Hocko
2015-09-21 23:33 ` David Rientjes
2015-09-21 23:33 ` David Rientjes
2015-09-22 5:33 ` Tetsuo Handa
2015-09-22 5:33 ` Tetsuo Handa
2015-09-22 23:32 ` David Rientjes
2015-09-22 23:32 ` David Rientjes
2015-09-23 12:03 ` Kyle Walker
2015-09-23 12:03 ` Kyle Walker
2015-09-24 11:50 ` Tetsuo Handa
2015-09-24 11:50 ` Tetsuo Handa
2015-09-19 14:44 ` Oleg Nesterov
2015-09-19 14:44 ` Oleg Nesterov
2015-09-21 23:27 ` David Rientjes
2015-09-21 23:27 ` David Rientjes
2015-09-19 8:25 ` Michal Hocko
2015-09-19 8:25 ` Michal Hocko
2015-09-19 8:22 ` Michal Hocko
2015-09-19 8:22 ` Michal Hocko
2015-09-21 23:08 ` David Rientjes
2015-09-21 23:08 ` David Rientjes
2015-09-19 15:03 ` can't oom-kill zap the victim's memory? Oleg Nesterov
2015-09-19 15:03 ` Oleg Nesterov
2015-09-19 15:10 ` Oleg Nesterov [this message]
2015-09-19 15:10 ` Oleg Nesterov
2015-09-19 15:58 ` Michal Hocko
2015-09-19 15:58 ` Michal Hocko
2015-09-20 13:16 ` Oleg Nesterov
2015-09-20 13:16 ` Oleg Nesterov
2015-09-19 22:24 ` Linus Torvalds
2015-09-19 22:24 ` Linus Torvalds
2015-09-19 22:54 ` Raymond Jennings
2015-09-19 23:00 ` Raymond Jennings
2015-09-19 23:00 ` Raymond Jennings
2015-09-19 23:13 ` Linus Torvalds
2015-09-19 23:13 ` Linus Torvalds
2015-09-20 9:33 ` Michal Hocko
2015-09-20 9:33 ` Michal Hocko
2015-09-20 13:06 ` Oleg Nesterov
2015-09-20 13:06 ` Oleg Nesterov
2015-09-20 12:56 ` Oleg Nesterov
2015-09-20 12:56 ` Oleg Nesterov
2015-09-20 18:05 ` Linus Torvalds
2015-09-20 18:05 ` Linus Torvalds
2015-09-20 18:21 ` Raymond Jennings
2015-09-20 18:23 ` Raymond Jennings
2015-09-20 19:07 ` Raymond Jennings
2015-09-20 19:07 ` Raymond Jennings
2015-09-21 13:57 ` Oleg Nesterov
2015-09-21 13:57 ` Oleg Nesterov
2015-09-21 13:44 ` Oleg Nesterov
2015-09-21 13:44 ` Oleg Nesterov
2015-09-21 14:24 ` Michal Hocko
2015-09-21 14:24 ` Michal Hocko
2015-09-21 15:32 ` Oleg Nesterov
2015-09-21 15:32 ` Oleg Nesterov
2015-09-21 16:12 ` Michal Hocko
2015-09-21 16:12 ` Michal Hocko
2015-09-22 16:06 ` Oleg Nesterov
2015-09-22 16:06 ` Oleg Nesterov
2015-09-22 23:04 ` David Rientjes
2015-09-22 23:04 ` David Rientjes
2015-09-23 20:59 ` Michal Hocko
2015-09-23 20:59 ` Michal Hocko
2015-09-24 21:15 ` David Rientjes
2015-09-24 21:15 ` David Rientjes
2015-09-25 9:35 ` Michal Hocko
2015-09-25 9:35 ` Michal Hocko
2015-09-25 16:14 ` Tetsuo Handa
2015-09-25 16:14 ` Tetsuo Handa
2015-09-28 16:18 ` Tetsuo Handa
2015-09-28 16:18 ` Tetsuo Handa
2015-09-28 22:28 ` David Rientjes
2015-09-28 22:28 ` David Rientjes
2015-10-02 12:36 ` Michal Hocko
2015-10-02 12:36 ` Michal Hocko
2015-10-02 19:01 ` Linus Torvalds
2015-10-02 19:01 ` Linus Torvalds
2015-10-05 14:44 ` Michal Hocko
2015-10-05 14:44 ` Michal Hocko
2015-10-07 5:16 ` Vlastimil Babka
2015-10-07 5:16 ` Vlastimil Babka
2015-10-07 10:43 ` Tetsuo Handa
2015-10-07 10:43 ` Tetsuo Handa
2015-10-08 9:40 ` Vlastimil Babka
2015-10-08 9:40 ` Vlastimil Babka
2015-10-06 7:55 ` Eric W. Biederman
2015-10-06 7:55 ` Eric W. Biederman
2015-10-06 8:49 ` Linus Torvalds
2015-10-06 8:49 ` Linus Torvalds
2015-10-06 8:55 ` Linus Torvalds
2015-10-06 8:55 ` Linus Torvalds
2015-10-06 14:52 ` Eric W. Biederman
2015-10-06 14:52 ` Eric W. Biederman
2015-10-03 6:02 ` Can't we use timeout based OOM warning/killing? Tetsuo Handa
2015-10-03 6:02 ` Tetsuo Handa
2015-10-06 14:51 ` Tetsuo Handa
2015-10-06 14:51 ` Tetsuo Handa
2015-10-12 6:43 ` Tetsuo Handa
2015-10-12 6:43 ` Tetsuo Handa
2015-10-12 15:25 ` Silent hang up caused by pages being not scanned? Tetsuo Handa
2015-10-12 15:25 ` Tetsuo Handa
2015-10-12 21:23 ` Linus Torvalds
2015-10-12 21:23 ` Linus Torvalds
2015-10-13 12:21 ` Tetsuo Handa
2015-10-13 12:21 ` Tetsuo Handa
2015-10-13 16:37 ` Linus Torvalds
2015-10-13 16:37 ` Linus Torvalds
2015-10-14 12:21 ` Tetsuo Handa
2015-10-14 12:21 ` Tetsuo Handa
2015-10-15 13:14 ` Michal Hocko
2015-10-15 13:14 ` Michal Hocko
2015-10-16 15:57 ` Michal Hocko
2015-10-16 15:57 ` Michal Hocko
2015-10-16 18:34 ` Linus Torvalds
2015-10-16 18:34 ` Linus Torvalds
2015-10-16 18:49 ` Tetsuo Handa
2015-10-16 18:49 ` Tetsuo Handa
2015-10-19 12:57 ` Michal Hocko
2015-10-19 12:57 ` Michal Hocko
2015-10-19 12:53 ` Michal Hocko
2015-10-19 12:53 ` Michal Hocko
2015-10-13 13:32 ` Michal Hocko
2015-10-13 13:32 ` Michal Hocko
2015-10-13 16:19 ` Tetsuo Handa
2015-10-13 16:19 ` Tetsuo Handa
2015-10-14 13:22 ` Michal Hocko
2015-10-14 13:22 ` Michal Hocko
2015-10-14 14:38 ` Tetsuo Handa
2015-10-14 14:38 ` Tetsuo Handa
2015-10-14 14:59 ` Michal Hocko
2015-10-14 14:59 ` Michal Hocko
2015-10-14 15:06 ` Tetsuo Handa
2015-10-14 15:06 ` Tetsuo Handa
2015-10-26 11:44 ` Newbie's question: memory allocation when reclaiming memory Tetsuo Handa
2015-10-26 11:44 ` Tetsuo Handa
2015-11-05 8:46 ` Vlastimil Babka
2015-11-05 8:46 ` Vlastimil Babka
2015-10-06 15:25 ` Can't we use timeout based OOM warning/killing? Linus Torvalds
2015-10-08 15:33 ` Tetsuo Handa
2015-10-08 15:33 ` Tetsuo Handa
2015-10-10 12:50 ` Tetsuo Handa
2015-10-10 12:50 ` Tetsuo Handa
2015-09-28 22:24 ` can't oom-kill zap the victim's memory? David Rientjes
2015-09-28 22:24 ` David Rientjes
2015-09-29 7:57 ` Tetsuo Handa
2015-09-29 7:57 ` Tetsuo Handa
2015-09-29 22:56 ` David Rientjes
2015-09-29 22:56 ` David Rientjes
2015-09-30 4:25 ` Tetsuo Handa
2015-09-30 4:25 ` Tetsuo Handa
2015-09-30 10:21 ` Tetsuo Handa
2015-09-30 10:21 ` Tetsuo Handa
2015-09-30 21:11 ` David Rientjes
2015-09-30 21:11 ` David Rientjes
2015-10-01 12:13 ` Tetsuo Handa
2015-10-01 12:13 ` Tetsuo Handa
2015-10-01 14:48 ` Michal Hocko
2015-10-01 14:48 ` Michal Hocko
2015-10-02 13:06 ` Tetsuo Handa
2015-10-02 13:06 ` Tetsuo Handa
2015-10-06 18:45 ` Oleg Nesterov
2015-10-06 18:45 ` Oleg Nesterov
2015-10-07 11:03 ` Tetsuo Handa
2015-10-07 11:03 ` Tetsuo Handa
2015-10-07 12:00 ` Oleg Nesterov
2015-10-07 12:00 ` Oleg Nesterov
2015-10-08 14:04 ` Michal Hocko
2015-10-08 14:04 ` Michal Hocko
2015-10-08 14:01 ` Michal Hocko
2015-10-08 14:01 ` Michal Hocko
2015-09-21 16:51 ` Tetsuo Handa
2015-09-21 16:51 ` Tetsuo Handa
2015-09-22 12:43 ` Oleg Nesterov
2015-09-22 12:43 ` Oleg Nesterov
2015-09-22 14:30 ` Tetsuo Handa
2015-09-22 14:30 ` Tetsuo Handa
2015-09-22 14:45 ` Oleg Nesterov
2015-09-22 14:45 ` Oleg Nesterov
2015-09-21 23:42 ` David Rientjes
2015-09-21 23:42 ` David Rientjes
2015-09-21 16:55 ` Linus Torvalds
2015-09-21 16:55 ` Linus Torvalds
2015-09-20 14:50 ` Tetsuo Handa
2015-09-20 14:50 ` Tetsuo Handa
2015-09-20 14:55 ` Oleg Nesterov
2015-09-20 14:55 ` Oleg Nesterov
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