From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f41.google.com (mail-pa0-f41.google.com [209.85.220.41]) by kanga.kvack.org (Postfix) with ESMTP id F37DE6B0038 for ; Thu, 3 Dec 2015 03:19:53 -0500 (EST) Received: by padhx2 with SMTP id hx2so64588833pad.1 for ; Thu, 03 Dec 2015 00:19:53 -0800 (PST) Received: from out21.biz.mail.alibaba.com (out21.biz.mail.alibaba.com. [205.204.114.132]) by mx.google.com with ESMTP id z12si10561837pfi.102.2015.12.03.00.19.51 for ; Thu, 03 Dec 2015 00:19:53 -0800 (PST) Reply-To: "Hillf Danton" From: "Hillf Danton" 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 Content-Language: zh-cn Sender: owner-linux-mm@kvack.org List-ID: To: David Rientjes Cc: Andrew Morton , chenjie6@huawei.com, linux-mm@kvack.org, linux-kernel , Michal Hocko , David.Woodhouse@intel.com > > 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, 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