Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752640AbbF3T3A (ORCPT ); Tue, 30 Jun 2015 15:29:00 -0400 Received: from arcturus.aphlor.org ([188.246.204.175]:45171 "EHLO arcturus.aphlor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750980AbbF3T2x (ORCPT ); Tue, 30 Jun 2015 15:28:53 -0400 Date: Tue, 30 Jun 2015 15:28:44 -0400 From: Dave Jones To: Josef Bacik Cc: Chris Mason , dsterba@suse.cz, Linux Kernel Subject: Re: [4.1-rc7] btrfs related VM_BUG_ON in filemap.c Message-ID: <20150630192844.GA2569@codemonkey.org.uk> Mail-Followup-To: Dave Jones , Josef Bacik , Chris Mason , dsterba@suse.cz, Linux Kernel References: <20150610134017.GA14803@codemonkey.org.uk> <55787743.4070308@fb.com> <20150616171443.GS6761@suse.cz> <55805A98.9020609@fb.com> <20150617133541.GA24428@codemonkey.org.uk> <20150630192006.GA14920@codemonkey.org.uk> <5592EC94.2080002@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5592EC94.2080002@fb.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-Spam-Score: -2.9 (--) X-Spam-Report: Spam report generated by SpamAssassin on "arcturus.aphlor.org" Content analysis details: (-2.9 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] X-Authenticated-User: davej@codemonkey.org.uk Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1354 Lines: 33 On Tue, Jun 30, 2015 at 03:23:00PM -0400, Josef Bacik wrote: > On 06/30/2015 03:20 PM, Dave Jones wrote: > > On Wed, Jun 17, 2015 at 09:35:41AM -0400, Dave Jones wrote: > > > > > page:ffffea00027cc640 count:4 mapcount:0 mapping:ffff8800af11d8a0 index:0x0 > > > flags: 0x4000000000000846(error|referenced|active|private) > > > page dumped because: VM_BUG_ON_PAGE(!PageLocked(page)) > > > ------------[ cut here ]------------ > > > kernel BUG at mm/filemap.c:745! > > > > Still occasionally bumping into this. > > The 'count:4 mapcount:0' is constant in every instance I've seen > > so far. Could that be a clue ? > > > > I've seen various page flags, but it's always !locked > > > > Ideas on additional debugging I could add ? > > Huh I just noticed that PG_Error seems to be set, is that the same for > every time? I wonder where that's getting set and why. I'll dig into > the areas we set that and see if I can spot anything. Thanks, Seems to be set every time yeah. I can try annotating those places that set it to see which one is triggering when I get home. Dave -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/