From: Michal Hocko <mhocko@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>,
Mel Gorman <mgorman@suse.de>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
Oleg Nesterov <oleg@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Hugh Dickins <hughd@google.com>,
Andrea Argangeli <andrea@kernel.org>,
Rik van Riel <riel@redhat.com>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 6/5] oom, oom_reaper: disable oom_reaper for
Date: Fri, 19 Feb 2016 19:34:19 +0100 [thread overview]
Message-ID: <20160219183419.GA30059@dhcp22.suse.cz> (raw)
In-Reply-To: <20160217094855.GC29196@dhcp22.suse.cz>
On Wed 17-02-16 10:48:55, Michal Hocko wrote:
> Hi Andrew,
> although this can be folded into patch 5
> (mm-oom_reaper-implement-oom-victims-queuing.patch) I think it would be
> better to have it separate and revert after we sort out the proper
> oom_kill_allocating_task behavior or handle exclusion at oom_reaper
> level.
An alternative would be something like the following. It is definitely
less hackish but it steals one bit in mm->flags. We do not seem to be
in shortage there now but who knows. Does this sound better? Later
changes might even consider the flag for the victim selection and ignore
those which already have the flag set. But I didn't think about it more
to form a patch yet.
---
>From 8b17e66a70edac65ecd6df411a675cf3d840a9fe Mon Sep 17 00:00:00 2001
From: Michal Hocko <mhocko@suse.com>
Date: Wed, 17 Feb 2016 10:40:41 +0100
Subject: [PATCH] oom, oom_reaper: disable oom_reaper for
oom_kill_allocating_task
Tetsuo has reported that oom_kill_allocating_task=1 will cause
oom_reaper_list corruption because oom_kill_process doesn't follow
standard OOM exclusion (aka ignores TIF_MEMDIE) and allows to enqueue
the same task multiple times - e.g. by sacrificing the same child
multiple times.
This patch fixes the issue by introducing a new MMF_OOM_KILLED mm flag
which is set in oom_kill_process atomically and oom reaper is disabled
if the flag was already set.
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Michal Hocko <mhocko@suse.com>
---
include/linux/sched.h | 2 ++
mm/oom_kill.c | 6 +++++-
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index c25996c336de..0552cd5696c2 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -509,6 +509,8 @@ static inline int get_dumpable(struct mm_struct *mm)
#define MMF_HAS_UPROBES 19 /* has uprobes */
#define MMF_RECALC_UPROBES 20 /* MMF_HAS_UPROBES can be wrong */
+#define MMF_OOM_KILLED 21 /* OOM killer has chosen this mm */
+
#define MMF_INIT_MASK (MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK)
struct sighand_struct {
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 7e9953a64489..32ce05b1aa10 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -678,7 +678,7 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p,
unsigned int victim_points = 0;
static DEFINE_RATELIMIT_STATE(oom_rs, DEFAULT_RATELIMIT_INTERVAL,
DEFAULT_RATELIMIT_BURST);
- bool can_oom_reap = true;
+ bool can_oom_reap;
/*
* If the task is already exiting, don't alarm the sysadmin or kill
@@ -740,6 +740,10 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p,
/* Get a reference to safely compare mm after task_unlock(victim) */
mm = victim->mm;
atomic_inc(&mm->mm_count);
+
+ /* Make sure we do not try to oom reap the mm multiple times */
+ can_oom_reap = !test_and_set_bit(MMF_OOM_KILLED, &mm->flags);
+
/*
* We should send SIGKILL before setting TIF_MEMDIE in order to prevent
* the OOM victim from depleting the memory reserves from the user
--
2.7.0
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2016-02-19 18:34 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-03 13:13 [PATCH 0/5] oom reaper v5 Michal Hocko
2016-02-03 13:13 ` [PATCH 1/5] mm, oom: introduce oom reaper Michal Hocko
2016-02-03 23:48 ` David Rientjes
2016-02-04 6:41 ` Michal Hocko
2016-02-06 13:22 ` Tetsuo Handa
2016-02-15 20:50 ` Michal Hocko
2016-02-03 13:13 ` [PATCH 2/5] oom reaper: handle mlocked pages Michal Hocko
2016-02-03 23:57 ` David Rientjes
2016-02-23 1:36 ` David Rientjes
2016-02-23 13:21 ` Michal Hocko
2016-02-29 3:19 ` Hugh Dickins
2016-02-29 13:41 ` Michal Hocko
2016-03-08 13:40 ` Michal Hocko
2016-03-08 20:07 ` Hugh Dickins
2016-03-09 8:26 ` Michal Hocko
2016-02-03 13:13 ` [PATCH 3/5] oom: clear TIF_MEMDIE after oom_reaper managed to unmap the address space Michal Hocko
2016-02-04 14:22 ` Tetsuo Handa
2016-02-04 14:43 ` Michal Hocko
2016-02-04 15:08 ` Tetsuo Handa
2016-02-04 16:31 ` Michal Hocko
2016-02-05 11:14 ` Tetsuo Handa
2016-02-06 8:30 ` Michal Hocko
2016-02-06 11:23 ` Tetsuo Handa
2016-02-15 20:47 ` Michal Hocko
2016-02-06 6:45 ` Michal Hocko
2016-02-06 14:33 ` Tetsuo Handa
2016-02-15 20:40 ` [PATCH 3.1/5] oom: make oom_reaper freezable Michal Hocko
2016-02-03 13:13 ` [PATCH 4/5] mm, oom_reaper: report success/failure Michal Hocko
2016-02-03 23:10 ` David Rientjes
2016-02-04 6:46 ` Michal Hocko
2016-02-04 22:31 ` David Rientjes
2016-02-05 9:26 ` Michal Hocko
2016-02-06 6:34 ` Michal Hocko
2016-02-03 13:14 ` [PATCH 5/5] mm, oom_reaper: implement OOM victims queuing Michal Hocko
2016-02-04 10:49 ` Tetsuo Handa
2016-02-04 14:53 ` Michal Hocko
2016-02-06 5:54 ` Tetsuo Handa
2016-02-06 8:37 ` Michal Hocko
2016-02-06 15:33 ` Tetsuo Handa
2016-02-15 20:15 ` Michal Hocko
2016-02-16 11:11 ` Tetsuo Handa
2016-02-16 15:53 ` Michal Hocko
2016-02-17 9:48 ` [PATCH 6/5] oom, oom_reaper: disable oom_reaper for Michal Hocko
2016-02-17 10:41 ` Tetsuo Handa
2016-02-17 11:33 ` Michal Hocko
2016-02-19 18:34 ` Michal Hocko [this message]
2016-02-20 2:32 ` [PATCH 6/5] oom, oom_reaper: disable oom_reaper for oom_kill_allocating_task Tetsuo Handa
2016-02-22 9:41 ` Michal Hocko
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