Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759282AbbLBXKf (ORCPT ); Wed, 2 Dec 2015 18:10:35 -0500 Received: from mail-pa0-f46.google.com ([209.85.220.46]:34573 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758117AbbLBXKb (ORCPT ); Wed, 2 Dec 2015 18:10:31 -0500 Date: Wed, 2 Dec 2015 15:10:28 -0800 (PST) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Andrew Morton , chenjie6@huawei.com cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, David.Woodhouse@intel.com, zhihui.gao@huawei.com, lizefan@huawei.com, Michal Hocko Subject: [patch] mm, oom: avoid attempting to kill init sharing same memory Message-ID: User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1826 Lines: 50 From: Chen Jie It's possible that an oom killed victim shares an ->mm with the init process and thus oom_kill_process() would end up trying to kill init as well. This has been shown in practice: Out of memory: Kill process 9134 (init) score 3 or sacrifice child Killed process 9134 (init) total-vm:1868kB, anon-rss:84kB, file-rss:572kB Kill process 1 (init) sharing same memory ... Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009 And this will result in a kernel panic. If a process is forked by init and selected for oom kill while still sharing init_mm, then it's likely this system is in a recoverable state. However, it's better not to try to kill init and allow the machine to panic due to unkillable processes. [rientjes@google.com: rewrote changelog] Acked-by: Michal Hocko Signed-off-by: Chen Jie Signed-off-by: David Rientjes --- I removed stable from this patch since the alternative would most likely be to panic the system for no killable processes anyway. There's a very small likelihood this patch would allow for a recoverable system. mm/oom_kill.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/oom_kill.c b/mm/oom_kill.c --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -608,6 +608,8 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p, continue; if (unlikely(p->flags & PF_KTHREAD)) continue; + if (!is_global_init(p)) + continue; if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) continue; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/