Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932545AbbLCIMF (ORCPT ); Thu, 3 Dec 2015 03:12:05 -0500 Received: from mail-wm0-f46.google.com ([74.125.82.46]:33604 "EHLO mail-wm0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932511AbbLCIMD (ORCPT ); Thu, 3 Dec 2015 03:12:03 -0500 Date: Thu, 3 Dec 2015 09:12:01 +0100 From: Michal Hocko To: David Rientjes Cc: Andrew Morton , chenjie6@huawei.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, David.Woodhouse@intel.com, zhihui.gao@huawei.com, lizefan@huawei.com Subject: Re: [patch] mm, oom: avoid attempting to kill init sharing same memory Message-ID: <20151203081200.GA9264@dhcp22.suse.cz> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1999 Lines: 57 On Wed 02-12-15 15:10:28, David Rientjes wrote: > 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. Agreed. > 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; > -- Michal Hocko SUSE Labs -- 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/