From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:34990 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751177AbbLJVad (ORCPT ); Thu, 10 Dec 2015 16:30:33 -0500 Date: Thu, 10 Dec 2015 16:30:24 -0500 From: Chris Mason To: Dave Jones CC: , , Subject: Re: !PageLocked BUG_ON hit in clear_page_dirty_for_io Message-ID: <20151210213024.GC11257@ret.masoncoding.com> References: <20151209042528.GA2413@codemonkey.org.uk> <20151210190220.GA11257@ret.masoncoding.com> <20151210193555.GA23535@codemonkey.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" In-Reply-To: <20151210193555.GA23535@codemonkey.org.uk> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Thu, Dec 10, 2015 at 02:35:55PM -0500, Dave Jones wrote: > On Thu, Dec 10, 2015 at 02:02:20PM -0500, Chris Mason wrote: > > On Tue, Dec 08, 2015 at 11:25:28PM -0500, Dave Jones wrote: > > > Not sure if I've already reported this one, but I've been seeing this > > > a lot this last couple days. > > > > > > kernel BUG at mm/page-writeback.c:2654! > > > invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC KASAN > > > CPU: 1 PID: 2566 Comm: trinity-c1 Tainted: G W 4.4.0-rc4-think+ #14 > > > task: ffff880462811b80 ti: ffff8800cd808000 task.ti: ffff8800cd808000 > > > RIP: 0010:[] [] clear_page_dirty_for_io+0x180/0x1d0 > > > > Huh, are you able to reproduce at will? From this code path it should > > mean somebody else is unlocking a page they don't own. > > pretty easily yeah. I hit it maybe a couple dozen times yesterday. > So if you've got some idea of printk's to spray anywhere I can give > that a shot. I'd rather try to trigger it here. Going to have to add some way to record which stack trace last unlocked and/or freed the page. -chris