From b52723c5607f7684c2c0c075f86f86da0d7fb6d0 Mon Sep 17 00:00:00 2001 From: KOSAKI Motohiro Date: Thu, 19 Aug 2010 14:13:39 -0700 Subject: oom: fix tasklist_lock leak Commit 0aad4b3124 ("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: [] 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 Reviewed-by: Minchan Kim Acked-by: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/oom_kill.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'mm') diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 17d48a67e7b..c48c5ef3ccf 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -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); } -- cgit v1.2.3