From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx136.postini.com [74.125.245.136]) by kanga.kvack.org (Postfix) with SMTP id 49BD26B0085 for ; Fri, 5 Oct 2012 03:05:24 -0400 (EDT) Date: Fri, 5 Oct 2012 09:05:21 +0200 From: Michal Hocko Subject: Re: [patch 1/2] mm: memcontrol: handle potential crash when rmap races with task exit Message-ID: <20121005070521.GB27757@dhcp22.suse.cz> References: <1349374157-20604-1-git-send-email-hannes@cmpxchg.org> <1349374157-20604-2-git-send-email-hannes@cmpxchg.org> <20121004184958.GG27536@dhcp22.suse.cz> <20121004201908.GA2625@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20121004201908.GA2625@cmpxchg.org> Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner Cc: Andrew Morton , Konstantin Khlebnikov , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org On Thu 04-10-12 16:19:08, Johannes Weiner wrote: > On Thu, Oct 04, 2012 at 08:49:58PM +0200, Michal Hocko wrote: > > On Thu 04-10-12 14:09:16, Johannes Weiner wrote: > > > page_referenced() counts only references of mm's that are associated > > > with the memcg hierarchy that is being reclaimed. However, if it > > > races with the owner of the mm exiting, mm->owner may be NULL. Don't > > > crash, just ignore the reference. > > > > This seems to be fixed by Hugh's patch 3a981f48 "memcg: fix use_hierarchy > > css_is_ancestor oops regression" which seems to be merged already. > > And look who acked the patch. I'll show myself out... My memory is a bit fuzzy but I remember we had two alternatives and Hugh's won. -- 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