Received: by 2002:ac0:a581:0:0:0:0:0 with SMTP id m1-v6csp2151385imm; Thu, 21 Jun 2018 07:59:55 -0700 (PDT) X-Google-Smtp-Source: ADUXVKKkDtS5PgGfLB31Pnd2N3yq93x5Z7KxRjYStFGmopMiaakDGaz8fwdZ68IeRcNMnr7/+4t2 X-Received: by 2002:a62:ea14:: with SMTP id t20-v6mr28039644pfh.117.1529593195028; Thu, 21 Jun 2018 07:59:55 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1529593194; cv=none; d=google.com; s=arc-20160816; b=Bs++qS+vePuvTuigWmDyOqk/GsKuk95uZ++qAPk4qDjlShIkcK59tUC72L1xLsSfVE sY04yjJP4xBNWm4Wdze+1GvAx0/lOootfBymtURtDgo3hWyhxOuiib3fgaMWdACagzWt IFJCYf1yjwp0ZO0RWckXhb7iOqqZBHguQwmucQlFG9P0szWz4j23d67ev4MybwhBibX2 GEm4ULOLyV/CuFr9cR1I8MZ6ZocWTeQlYgGZinEX1ySfHSKMAIRD+PiLStWH51ClWD4U RAJjWisUduSZqMFbFHx0T4QSmndH9oIeRidEW9H/KrM3H2Ou577zZH11CEszJtsJaEyK NArw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:user-agent:in-reply-to :content-disposition:mime-version:references:message-id:subject:cc :to:from:date:arc-authentication-results; bh=iseDc57sBzVI1Q5nsT3/moFUpjf5Vj332DlkL4ZHXFE=; b=j6P/I0QZSyNoAE7SjyOpq0nA00r0qB4Dw4WyMmVHiGuiY1rrpX5CDPjPHc5exFHuFD 52op4bZf1E1qYpwEtZcOcB84AyRB7AmNWYloBoAyZh8mbJYe0oPMJvGsOtAolJqzj7dj U1h5Bk18QR106DQ4nbxpPJjs/sdx43GPGxjt4KxcU6pqGDfP1sfjja4DgZ8nG2Omvxoc aL6y+B9XE3om3vfqdQAXDckcfDuRZphbHVsat6omTvtupoJsL6LW9V0EL3XngoAma0jJ Tv4maKLUllh+FNfqG6fUCzXYhesztgBW6zvhIQctO6OfQFcwlijhdA8vZp0tzVE0FKMy pulw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id t69-v6si4192636pgd.55.2018.06.21.07.59.41; Thu, 21 Jun 2018 07:59:54 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933287AbeFUO6c (ORCPT + 99 others); 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.