Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752939AbYJ1BNQ (ORCPT ); Mon, 27 Oct 2008 21:13:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752104AbYJ1BM4 (ORCPT ); Mon, 27 Oct 2008 21:12:56 -0400 Received: from hera.kernel.org ([140.211.167.34]:54849 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752087AbYJ1BMz (ORCPT ); Mon, 27 Oct 2008 21:12:55 -0400 Message-ID: <490666D6.8090603@kernel.org> Date: Tue, 28 Oct 2008 10:11:50 +0900 From: Tejun Heo User-Agent: Thunderbird 2.0.0.12 (X11/20071114) MIME-Version: 1.0 To: Mike Anderson CC: James Bottomley , Jens Axboe , linux-scsi , IDE/ATA development list , Linux Kernel Subject: Re: Timeout regression introduced by 242f9dcb8ba6f68fcd217a119a7648a4f69290e9 References: <49043C7C.8050207@kernel.org> <1225034105.3958.4.camel@localhost.localdomain> <49051EA4.3040403@kernel.org> <20081027213006.GB17946@linux.vnet.ibm.com> In-Reply-To: <20081027213006.GB17946@linux.vnet.ibm.com> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Tue, 28 Oct 2008 01:11:55 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1790 Lines: 38 Mike Anderson wrote: > Tejun Heo wrote: >> James Bottomley wrote: >>> On Sun, 2008-10-26 at 18:46 +0900, Tejun Heo wrote: >>>> Hello, Jens. >>>> >>>> Commit 242f9dcb8ba6f68fcd217a119a7648a4f69290e9 introduces a strange >>>> regression for libata. The second timeout gives puts different >>>> pointer from the issued command onto eh_cmd_q breaking libata EH >>>> command matching which triggers WARN_ON() in ata_eh_finish() and hangs >>>> command processing or causes oops later depending on circumstances. >>>> >>>> Here are logs with induced timeouts (patch attached). In commit >>>> 242f9dcb8, the XXX messages for the second timeout shows different >>>> scsi_cmd pointers for eh_cmd_q and qc->scmd which is initialized by >>>> ata_scsi_qc_new() during command translation. >>> I can't see a way we could be getting a different command passed in from >>> the actual one, since the only way to lose the command from the request >>> is to go through the command completion routines which free it (and end >>> the request). >> I have no idea either. It's something in the timeout logic because on >> the issue path the scmd pointer is identical but on tiemout pointer >> for another scmd is queued on eh_cmd_q, which doesn't make much sense. >> > > I was trying to recreate this error using ata_ram wth v2.6.28-rc2. > Currently I am not able to see this error on timeout recovery using this > setup. Does IO load (or other factors) effect the error being seen? Not at all. That's the only write command I issued. -- tejun -- 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/