From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 79DB0C43141 for ; Thu, 21 Jun 2018 14:58:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3C99020837 for ; Thu, 21 Jun 2018 14:58:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3C99020837 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933293AbeFUO6c (ORCPT ); Thu, 21 Jun 2018 10:58:32 -0400 Received: from mga01.intel.com ([192.55.52.88]:13547 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933002AbeFUO6a (ORCPT ); Thu, 21 Jun 2018 10:58:30 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 Jun 2018 07:58:30 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,252,1526367600"; d="scan'208";a="65149987" Received: from unknown (HELO localhost.localdomain) ([10.232.112.44]) by fmsmga004.fm.intel.com with ESMTP; 21 Jun 2018 07:58:29 -0700 Date: Thu, 21 Jun 2018 09:01:43 -0600 From: Keith Busch To: "jianchao.wang" Cc: Christoph Hellwig , axboe@kernel.dk, martin.petersen@oracle.com, josef@toxicpanda.com, ulf.hansson@linaro.org, linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/5]stop normal completion path entering a timeout req Message-ID: <20180621150143.GA26712@localhost.localdomain> References: <1529500964-28429-1-git-send-email-jianchao.w.wang@oracle.com> <20180620181601.GA24145@localhost.localdomain> <20180621081900.GA5183@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 21, 2018 at 09:13:30PM +0800, jianchao.wang wrote: > Hi Christoph > > On 06/21/2018 04:19 PM, Christoph Hellwig wrote: > > On Thu, Jun 21, 2018 at 09:43:26AM +0800, jianchao.wang wrote: > >> So we have to preserve the ability of block layer that it could prevent > >> IO completion path from entering a timeout request. > >> > >> With scsi-debug module, I tried to simulate a scenario where timeout and IO > >> completion path could occur concurrently, the system ran into crash easily. > > > > Trace, please. With the latest kernel. I'm not saying that there > > is nothing to fix, but the mode of never completing once timeout > > requests as currently done is SCSI is clearly broken. > > > > Sorry, I don't quite get your point. > Do you mean we should do the modification in the scsi layer ? I think it would just be helpful to start with the stack trace of your observed crash + the reproduction steps so the problem (and hopefully a solution) can be better understood.