From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752526AbdARJq7 (ORCPT ); Wed, 18 Jan 2017 04:46:59 -0500 Received: from outbound-smtp09.blacknight.com ([46.22.139.14]:36990 "EHLO outbound-smtp09.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752329AbdARJp2 (ORCPT ); Wed, 18 Jan 2017 04:45:28 -0500 Date: Wed, 18 Jan 2017 09:45:13 +0000 From: Mel Gorman To: Vlastimil Babka Cc: Ganapatrao Kulkarni , Michal Hocko , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC 1/4] mm, page_alloc: fix check for NULL preferred_zone Message-ID: <20170118094513.v6nlnpwnfl6pnkiv@techsingularity.net> References: <20170117221610.22505-1-vbabka@suse.cz> <20170117221610.22505-2-vbabka@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20170117221610.22505-2-vbabka@suse.cz> User-Agent: Mutt/1.6.2 (2016-07-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 17, 2017 at 11:16:07PM +0100, Vlastimil Babka wrote: > Since commit c33d6c06f60f ("mm, page_alloc: avoid looking up the first zone in > a zonelist twice") we have a wrong check for NULL preferred_zone, which can > theoretically happen due to concurrent cpuset modification. We check the > zoneref pointer which is never NULL and we should check the zone pointer. > > Fixes: c33d6c06f60f ("mm, page_alloc: avoid looking up the first zone in a zonelist twice") > Signed-off-by: Vlastimil Babka Acked-by: Mel Gorman -- Mel Gorman SUSE Labs