From: Michal Hocko <mhocko@xxxxxxxx>
0-day robot has encountered the following:
[ 82.694232] Out of memory: Kill process 3914 (trinity-c0) score 167 or sacrifice child
[ 82.695110] Killed process 3914 (trinity-c0) total-vm:55864kB, anon-rss:1512kB, file-rss:1088kB, shmem-rss:25616kB
[ 82.706724] oom_reaper: reaped process 3914 (trinity-c0), now anon-rss:0kB, file-rss:0kB, shmem-rss:26488kB
[ 82.715540] oom_reaper: reaped process 3914 (trinity-c0), now anon-rss:0kB, file-rss:0kB, shmem-rss:26900kB
[ 82.717662] oom_reaper: reaped process 3914 (trinity-c0), now anon-rss:0kB, file-rss:0kB, shmem-rss:26900kB
[ 82.725804] oom_reaper: reaped process 3914 (trinity-c0), now anon-rss:0kB, file-rss:0kB, shmem-rss:27296kB
[ 82.739091] oom_reaper: reaped process 3914 (trinity-c0), now anon-rss:0kB, file-rss:0kB, shmem-rss:28148kB
oom_reaper is trying to reap the same task again and again. This
is possible only when the oom killer is bypassed because of
task_will_free_mem because we skip over tasks with MMF_OOM_REAPED
already set during select_bad_process. Teach task_will_free_mem to skip
over MMF_OOM_REAPED tasks as well because they will be unlikely to free
anything more.
Analyzed-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
---
mm/oom_kill.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index dacfb6ab7b04..d6e121decb1a 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -766,6 +766,15 @@ bool task_will_free_mem(struct task_struct *task)
return true;
}
+ /*
+ * This task has already been drained by the oom reaper so there are
+ * only small chances it will free some more
+ */
+ if (test_bit(MMF_OOM_REAPED, &mm->flags)) {
+ task_unlock(p);
+ return false;
+ }
+
/* pin the mm to not get freed and reused */
atomic_inc(&mm->mm_count);
task_unlock(p);
--
2.8.1
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