From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-f70.google.com (mail-lf0-f70.google.com [209.85.215.70]) by kanga.kvack.org (Postfix) with ESMTP id 36A7E6B0005 for ; Tue, 7 Jun 2016 02:37:43 -0400 (EDT) Received: by mail-lf0-f70.google.com with SMTP id k192so14250206lfb.1 for ; Mon, 06 Jun 2016 23:37:43 -0700 (PDT) Received: from mail-wm0-f53.google.com (mail-wm0-f53.google.com. [74.125.82.53]) by mx.google.com with ESMTPS id a138si23279012wmd.114.2016.06.06.23.37.41 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 06 Jun 2016 23:37:41 -0700 (PDT) Received: by mail-wm0-f53.google.com with SMTP id v199so3872038wmv.0 for ; Mon, 06 Jun 2016 23:37:41 -0700 (PDT) Date: Tue, 7 Jun 2016 08:37:39 +0200 From: Michal Hocko Subject: Re: [PATCH 06/10] mm, oom: kill all tasks sharing the mm Message-ID: <20160607063738.GB12305@dhcp22.suse.cz> References: <1464945404-30157-1-git-send-email-mhocko@kernel.org> <1464945404-30157-7-git-send-email-mhocko@kernel.org> <20160606232007.GA624@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160606232007.GA624@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Oleg Nesterov , David Rientjes Cc: linux-mm@kvack.org, Tetsuo Handa , Vladimir Davydov , Andrew Morton , LKML On Tue 07-06-16 01:20:08, Oleg Nesterov wrote: > On 06/06, David Rientjes wrote: > > > > > There is a potential race where we kill the oom disabled task which is > > > highly unlikely but possible. It would happen if __set_oom_adj raced > > > with select_bad_process and then it is OK to consider the old value or > > > with fork when it should be acceptable as well. > > > Let's add a little note to the log so that people would tell us that > > > this really happens in the real life and it matters. > > > > > > > We cannot kill oom disabled processes at all, little race or otherwise. > > But this change doesn't really make it worse? Exactly, the race was always there. We could mitigate it to some degree by (ab)using oom_lock in __set_oom_adj. But I guess this is just an overkill. -- 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