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authorMichal Hocko <mhocko@suse.com>2016-03-25 14:20:36 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-25 16:37:42 -0700
commit855b018325737f7691f9b7d86339df40aa4e47c3 (patch)
tree53593c573d50f6ae6f46d05a8339528f44b99b5b
parent03049269de433cb5fe2859be9ae4469ceb1163ed (diff)
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. Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/sched.h2
-rw-r--r--mm/oom_kill.c6
2 files changed, 7 insertions, 1 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 788f223f8f8f..c2d2d7c5d463 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -512,6 +512,8 @@ 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 f6d4ae9f1c69..1a21819a8e5e 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -680,7 +680,7 @@ 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
@@ -742,6 +742,10 @@ 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