Commit af8e15cc authored Apr 01, 2016 by Michal Hocko Committed by Linus Torvalds Apr 01, 2016

oom, oom_reaper: do not enqueue task if it is on the oom_reaper_list head

Commit bb29902a ("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: bb29902a ("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>

parent bbe3de25

mm/oom_kill.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -547,7 +547,11 @@ static int oom_reaper(void *unused)

		static void wake_oom_reaper(struct task_struct *tsk)
		{
		if (!oom_reaper_th \|\| tsk->oom_reaper_list)
		if (!oom_reaper_th)
		return;

		/* tsk is already queued? */
		if (tsk == oom_reaper_list \|\| tsk->oom_reaper_list)
		return;

		get_task_struct(tsk);

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