From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752746AbcFCJRw (ORCPT ); Fri, 3 Jun 2016 05:17:52 -0400 Received: from mail-wm0-f67.google.com ([74.125.82.67]:34766 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752018AbcFCJQ5 (ORCPT ); Fri, 3 Jun 2016 05:16:57 -0400 From: Michal Hocko To: Cc: Tetsuo Handa , David Rientjes , Oleg Nesterov , Vladimir Davydov , Andrew Morton , LKML , Michal Hocko Subject: [PATCH 08/10] mm, oom: task_will_free_mem should skip oom_reaped tasks Date: Fri, 3 Jun 2016 11:16:42 +0200 Message-Id: <1464945404-30157-9-git-send-email-mhocko@kernel.org> X-Mailer: git-send-email 2.8.1 In-Reply-To: <1464945404-30157-1-git-send-email-mhocko@kernel.org> References: <1464945404-30157-1-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 | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 64dbffa708fd..70992f0f1b78 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -742,6 +742,16 @@ bool task_will_free_mem(struct task_struct *task) return false; mm = p->mm; + + /* + * 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; + } + if (atomic_read(&mm->mm_users) <= 1) { task_unlock(p); return true; -- 2.8.1