oom, oom_reaper: do not enqueue task if it is on the oom_reaper_list head
commitaf8e15cc85a253155fdcea707588bf6ddfc0be2e
authorMichal Hocko <mhocko@suse.com>
Fri, 1 Apr 2016 21:31:34 +0000 (1 14:31 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 1 Apr 2016 22:03:37 +0000 (1 17:03 -0500)
treef2e5c0a39e0916f76310e4f923f00055498fdb62
parentbbe3de2560280c0420d36a192e69f2772e893cf4
oom, oom_reaper: do not enqueue task if it is on the oom_reaper_list head

Commit bb29902a7515 ("oom, oom_reaper: protect oom_reaper_list using
simpler way") has simplified the check for tasks already enqueued for
the oom reaper by checking tsk->oom_reaper_list != NULL.  This check is
not sufficient because the tsk might be the head of the queue without
any other tasks queued and then we would simply lockup looping on the
same task.  Fix the condition by checking for the head as well.

Fixes: bb29902a7515 ("oom, oom_reaper: protect oom_reaper_list using simpler way")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/oom_kill.c