From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f52.google.com (mail-wm0-f52.google.com [74.125.82.52]) by kanga.kvack.org (Postfix) with ESMTP id 31B616B0257 for ; Thu, 3 Dec 2015 03:12:04 -0500 (EST) Received: by wmvv187 with SMTP id v187so14506767wmv.1 for ; Thu, 03 Dec 2015 00:12:03 -0800 (PST) Received: from mail-wm0-f45.google.com (mail-wm0-f45.google.com. [74.125.82.45]) by mx.google.com with ESMTPS id z186si13122373wmz.15.2015.12.03.00.12.03 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 03 Dec 2015 00:12:03 -0800 (PST) Received: by wmvv187 with SMTP id v187so14506268wmv.1 for ; Thu, 03 Dec 2015 00:12:02 -0800 (PST) Date: Thu, 3 Dec 2015 09:12:01 +0100 From: Michal Hocko 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: Sender: owner-linux-mm@kvack.org List-ID: 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 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, 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