Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932600AbbLCIgr (ORCPT ); Thu, 3 Dec 2015 03:36:47 -0500 Received: from out4133-18.mail.aliyun.com ([42.120.133.18]:61636 "EHLO out4133-18.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759146AbbLCIgo (ORCPT ); Thu, 3 Dec 2015 03:36:44 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R181e4;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e02c03283;MF=hillf.zj@alibaba-inc.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_----4IIlBAl; Reply-To: "Hillf Danton" From: "Hillf Danton" To: "David Rientjes" Cc: "Andrew Morton" , , , "linux-kernel" , "Michal Hocko" , Subject: Re: [patch] mm, oom: avoid attempting to kill init sharing same memory Date: Thu, 03 Dec 2015 16:19:34 +0800 Message-ID: <05dd01d12da3$5888bb10$099a3130$@alibaba-inc.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Outlook 14.0 Thread-Index: AdEtoxCSZ7MSC3x/TYyYJKeamqBvkg== Content-Language: zh-cn Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1977 Lines: 57 > > 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 > --- Acked-by: Hillf Danton > 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/