From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161491AbcE3P4u (ORCPT ); Mon, 30 May 2016 11:56:50 -0400 Received: from outbound-smtp02.blacknight.com ([81.17.249.8]:50516 "EHLO outbound-smtp02.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932508AbcE3P4s (ORCPT ); Mon, 30 May 2016 11:56:48 -0400 Date: Mon, 30 May 2016 16:56:45 +0100 From: Mel Gorman To: Geert Uytterhoeven Cc: Andrew Morton , Linux Kernel Mailing List , Linux MM , linux-m68k Subject: Re: BUG: scheduling while atomic: cron/668/0x10c9a0c0 (was: Re: mm, page_alloc: avoid looking up the first zone in a zonelist twice) Message-ID: <20160530155644.GP2527@techsingularity.net> References: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 30, 2016 at 03:13:40PM +0200, Geert Uytterhoeven wrote: > > The benefit is negligible and the results are within the noise but each > > cycle counts. > > > > Signed-off-by: Mel Gorman > > Cc: Vlastimil Babka > > Cc: Jesper Dangaard Brouer > > Signed-off-by: Andrew Morton > > Signed-off-by: Linus Torvalds > > About one week ago, I started seeing an obscure intermittent crash during > system shutdown on m68k/ARAnyM using atari_defconfig. > The crash isn't 100% reproducible, but it happens during ca. 1 out of 5 > shutdowns. > > I finally managed to bisect it to the above commit. > I did verify that the parent commit didn't crash after 60 tries. > Unfortunately I couldn't revert the offending commit on top of v4.7-rc1, due to > conflicting changes. > > Do you have any idea what's going wrong? There isn't anything obvious from the crash log you showed but can you try the following just in case? diff --git a/mm/page_alloc.c b/mm/page_alloc.c index dba8cfd0b2d6..f2c1e47adc11 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3232,6 +3232,9 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, * allocations are system rather than user orientated */ ac->zonelist = node_zonelist(numa_node_id(), gfp_mask); + ac->preferred_zoneref = first_zones_zonelist(ac->zonelist, + ac->high_zoneidx, ac->nodemask); + ac->classzone_idx = zonelist_zone_idx(ac->preferred_zoneref); page = get_page_from_freelist(gfp_mask, order, ALLOC_NO_WATERMARKS, ac); if (page)