oom: fix tasklist_lock leak (b52723c5) · Commits · 戴 / test

Commit ("oom: fold __out_of_memory into out_of_memory") introduced a tasklist_lock leak. Then it caused following obvious danger warnings and panic. ================================================ [ BUG: lock held when returning to user space! ] ------------------------------------------------ rsyslogd/1422 is leaving the kernel with locks still held! 1 lock held by rsyslogd/1422: #0: (tasklist_lock){.+.+.+}, at: [<ffffffff810faf64>] out_of_memory+0x164/0x3f0 BUG: scheduling while atomic: rsyslogd/1422/0x00000002 INFO: lockdep is turned off. This patch fixes it. Signed-off-by:

KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by:

Minchan Kim <minchan.kim@gmail.com> Acked-by:

David Rientjes <rientjes@google.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/oom_kill.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -646,6 +646,7 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
		unsigned long freed = 0;
		unsigned int points;
		enum oom_constraint constraint = CONSTRAINT_NONE;
		int killed = 0;

		blocking_notifier_call_chain(&oom_notify_list, 0, &freed);
		if (freed > 0)
		@@ -683,7 +684,7 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
		if (!oom_kill_process(current, gfp_mask, order, 0, totalpages,
		NULL, nodemask,
		"Out of memory (oom_kill_allocating_task)"))
		return;
		goto out;
		}

		retry:
		@@ -691,7 +692,7 @@ retry:
		constraint == CONSTRAINT_MEMORY_POLICY ? nodemask :
		NULL);
		if (PTR_ERR(p) == -1UL)
		return;
		goto out;

		/* Found nothing?!?! Either we hang forever, or we panic. */
		if (!p) {
		@@ -703,13 +704,15 @@ retry:
		if (oom_kill_process(p, gfp_mask, order, points, totalpages, NULL,
		nodemask, "Out of memory"))
		goto retry;
		killed = 1;
		out:
		read_unlock(&tasklist_lock);

		/*
		* Give "p" a good chance of killing itself before we
		* retry to allocate memory unless "p" is current
		*/
		if (!test_thread_flag(TIF_MEMDIE))
		if (killed && !test_thread_flag(TIF_MEMDIE))
		schedule_timeout_uninterruptible(1);
		}

Admin message