From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752374Ab2AQRfH (ORCPT ); Tue, 17 Jan 2012 12:35:07 -0500 Received: from mail-iy0-f174.google.com ([209.85.210.174]:48412 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750777Ab2AQRfF (ORCPT ); Tue, 17 Jan 2012 12:35:05 -0500 Date: Tue, 17 Jan 2012 09:35:00 -0800 From: Tejun Heo To: Chris Mason Cc: Jens Axboe , LKML Subject: Re: cfq crashing on boot with CONFIG_DEBUG_PAGE_ALLOC (linus master) Message-ID: <20120117173500.GA6762@google.com> References: <20120117161024.GC30322@shiny> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120117161024.GC30322@shiny> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 17, 2012 at 11:10:24AM -0500, Chris Mason wrote: > Hi everyone, > > Looks like cfq is using stale pages, I'm getting crashes on boot with > CONFIG_DEBUG_PAGE_ALLOC enabled. The oops leads to crashing in > cfqq_type, and if you add some fuzz for inlining, it looks like we're > here: > > (gdb) list *cfq_insert_request+0x3f5 > 0xffffffff812683d8 is in cfq_insert_request (block/cfq-iosched.c:3131). > 3126 > 3127 /* > 3128 * workload type is changed, don't save slice, otherwise preempt > 3129 * doesn't happen > 3130 */ > 3131 if (cfqq_type(old_cfqq) != cfqq_type(cfqq)) > 3132 cfqq->cfqg->saved_workload_slice = 0; > 3133 > 3134 /* > 3135 * Put the new queue at the front of the of the current list, > > It seems like the most likely reason is that old_cfqq was previously > freed: > > struct cfq_queue *old_cfqq = cfqd->active_queue; Does the following patch resolve the problem? http://article.gmane.org/gmane.linux.kernel.next/20340/raw Thanks. -- tejun