From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f181.google.com (mail-pf0-f181.google.com [209.85.192.181]) by kanga.kvack.org (Postfix) with ESMTP id 1EE5D6B0038 for ; Wed, 2 Dec 2015 18:10:32 -0500 (EST) Received: by pfdd184 with SMTP id d184so2384946pfd.3 for ; Wed, 02 Dec 2015 15:10:31 -0800 (PST) Received: from mail-pf0-x22b.google.com (mail-pf0-x22b.google.com. [2607:f8b0:400e:c00::22b]) by mx.google.com with ESMTPS id n18si7567839pfb.35.2015.12.02.15.10.31 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 02 Dec 2015 15:10:31 -0800 (PST) Received: by pfdd184 with SMTP id d184so2384877pfd.3 for ; Wed, 02 Dec 2015 15:10:31 -0800 (PST) Date: Wed, 2 Dec 2015 15:10:28 -0800 (PST) From: David Rientjes Subject: [patch] mm, oom: avoid attempting to kill init sharing same memory Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: 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 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org