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 046F4C43140 for ; Thu, 21 Jun 2018 08:09:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BCE5120883 for ; Thu, 21 Jun 2018 08:09:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BCE5120883 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de 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 S932734AbeFUIJr (ORCPT ); Thu, 21 Jun 2018 04:09:47 -0400 Received: from verein.lst.de ([213.95.11.211]:50527 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932654AbeFUIJp (ORCPT ); Thu, 21 Jun 2018 04:09:45 -0400 Received: by newverein.lst.de (Postfix, from userid 2407) id 2E3347F0E0; Thu, 21 Jun 2018 10:19:00 +0200 (CEST) Date: Thu, 21 Jun 2018 10:19:00 +0200 From: Christoph Hellwig To: "jianchao.wang" Cc: Keith Busch , axboe@kernel.dk, hch@lst.de, 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: <20180621081900.GA5183@lst.de> References: <1529500964-28429-1-git-send-email-jianchao.w.wang@oracle.com> <20180620181601.GA24145@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) 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 09:43:26AM +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.