From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262337AbTJTIIq (ORCPT ); Mon, 20 Oct 2003 04:08:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262356AbTJTIIp (ORCPT ); Mon, 20 Oct 2003 04:08:45 -0400 Received: from dyn-ctb-210-9-246-89.webone.com.au ([210.9.246.89]:42759 "EHLO chimp.local.net") by vger.kernel.org with ESMTP id S262337AbTJTIIm (ORCPT ); Mon, 20 Oct 2003 04:08:42 -0400 Message-ID: <3F9397ED.8040004@cyberone.com.au> Date: Mon, 20 Oct 2003 18:08:13 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030827 Debian/1.4-3 X-Accept-Language: en MIME-Version: 1.0 To: Jens Axboe CC: Andrew Morton , Peter Osterlund , linux-kernel@vger.kernel.org Subject: Re: 2.6.0-test8, DEBUG_SLAB, oops in as_latter_request() References: <20031019142042.2f41eb68.akpm@osdl.org> <3F932B81.2040202@cyberone.com.au> <20031020070924.GU1128@suse.de> In-Reply-To: <20031020070924.GU1128@suse.de> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Jens Axboe wrote: >On Mon, Oct 20 2003, Nick Piggin wrote: > >> >>Andrew Morton wrote: >> >> >>>Peter Osterlund wrote: >>> >>> >>>>I was running 2.6.0-test8 compiled with CONFIG_DEBUG_SLAB=y. When >>>>testing the CDRW packet writing driver, I got an oops in >>>>as_latter_request. (Full oops at the end of this message.) It is >>>>repeatable and happens because arq->rb_node.rb_right is uninitialized. >>>> >>>> >>>deadline seems to have the same problem. >>> >>>We may as well squish this with the big hammer? >>> >>> >>Thanks for the report, Peter. >> >>The request is a special request, so either blk_attempt_remerge should >>never be called on it, or blk_attempt_remerge (or as_latter_request) should >>check for this. Its up to Jens. >> >>I would say to stick something like >>if (!rq_mergeable(rq)) >> return; >> >>into blk_attempt_remerge. >> >>I'd say we shouldn't expect drivers to try to get this right. >> > >attempt_merge() already includes such a check. To me it looks really >buggy that elv_latter_request() cannot be called on non-fs requests, I'd >rather get that fixed like Peter suggests. elv_latter_request() should >work on all requests in the io sched queue, period. > I don't have a problem with that. Peter's patch it is.