From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751774AbcEaKOC (ORCPT ); Tue, 31 May 2016 06:14:02 -0400 Received: from outbound-smtp07.blacknight.com ([46.22.139.12]:37096 "EHLO outbound-smtp07.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750783AbcEaKOA (ORCPT ); Tue, 31 May 2016 06:14:00 -0400 Date: Tue, 31 May 2016 11:13:56 +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: <20160531101356.GS2527@techsingularity.net> References: <20160530155644.GP2527@techsingularity.net> <20160530185616.GQ2527@techsingularity.net> 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 Tue, May 31, 2016 at 11:28:05AM +0200, Geert Uytterhoeven wrote: > Hi Mel, > > On Mon, May 30, 2016 at 8:56 PM, Mel Gorman wrote: > > Thanks. Please try the following instead > > > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > index bb320cde4d6d..557549c81083 100644 > > --- a/mm/page_alloc.c > > +++ b/mm/page_alloc.c > > @@ -3024,6 +3024,7 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags, > > apply_fair = false; > > fair_skipped = false; > > reset_alloc_batches(ac->preferred_zoneref->zone); > > + z = ac->preferred_zoneref; > > goto zonelist_scan; > > } > > Thanks a lot, that seems to fix the issue!. > > Tested-by: Geert Uytterhoeven > > JFTR, without the fix, sometimes I get a different, but equally obscure, crash > than the one I posted before: > I'm afraid I don't recognise it. Given the nature of the previous bug though, I have a vague suspicion that someone is not handling a page allocation failure properly and goes boom later. -- Mel Gorman SUSE Labs