From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161106AbcFBODO (ORCPT ); Thu, 2 Jun 2016 10:03:14 -0400 Received: from mail-wm0-f65.google.com ([74.125.82.65]:36588 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932892AbcFBODL (ORCPT ); Thu, 2 Jun 2016 10:03:11 -0400 From: Michal Hocko To: Cc: Tetsuo Handa , David Rientjes , Oleg Nesterov , LKML , Michal Hocko Subject: [PATCH 7/6] mm, oom: task_will_free_mem should skip oom_reaped tasks Date: Thu, 2 Jun 2016 16:03:03 +0200 Message-Id: <1464876183-15559-1-git-send-email-mhocko@kernel.org> X-Mailer: git-send-email 2.8.1 In-Reply-To: <1464613556-16708-1-git-send-email-mhocko@kernel.org> References: <1464613556-16708-1-git-send-email-mhocko@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Michal Hocko 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 Signed-off-by: Michal Hocko --- 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