Received: by 2002:ac0:a581:0:0:0:0:0 with SMTP id m1-v6csp1722779imm; Thu, 21 Jun 2018 01:10:38 -0700 (PDT) X-Google-Smtp-Source: ADUXVKLKKJ+Hu2r79fM3K2HClt4C7mkfS98dm6l/Xqj5m4y1tUs+iDonB2SiNXGLIOWZrKpKCMFs X-Received: by 2002:a17:902:583:: with SMTP id f3-v6mr23335732plf.115.1529568638652; Thu, 21 Jun 2018 01:10:38 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1529568638; cv=none; d=google.com; s=arc-20160816; b=kQPptymJtQvI8y68v8KQ+GurdK1n9hs6wiqfAmU6IFCrVc4D2gA1JLGYat0GfQPhdl TGCWa08enc0RUFPbOfSyVeh5vgYjAxIxSdgDeqAPp3yj+fTVf2RVZy24hHL3+6Bbks/Z 5vkYzZ0M0N9dPwBbEvN++PHnE9XYctDPbEJHECRgIZ2GkCoILnlBzRwFRr8R8h38AbNi 0ch+URaiosIDQ0E5y6uc0NxrfoO7pl+EA15MBX+7fEkfJAkUkvpcgh6jfpltPEim/6SL oT0hZybWr+llsKN33aX3GbFqwqPhv6CK1nIpeObjj4+oIrmNiZrs7HDDBk6jtY/csvF2 mGng== 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=20FJueHiQlKzl29xpcwI/G5IkdbCZ5Z5qlimq4gIQl8=; b=zYREWc68bzKE0Jt0wJwz2zasqkRqeoLERB1LYxkJP0Ol5lSM+iBZpZq2BikvaYR3Ex Vlr/MMObebw9KzaKsMqyLsl8hfNT0NXCL/AnOANHCPUE4bbrLa61vlz17qxLC8olVRlJ l2DO+egsIAY38myXpSCkDxy6egPsorH9o8dgt82hhfAw5F3TiUIk9Cka6v14AAdUnO42 5ek45Be7QQShAGgryD641Zpyn5XKRO4aNRG6G5V7d3T7pKiUC1oh21zBnHjPltwqvP4N nwiCntTCXQI8WVKVGACF3F/DS8Ud1PPko6ByLV0xXU5NINWPRFd7KJetG8cK7x5/PQVI VcBA== 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 Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id n63-v6si3389514pga.406.2018.06.21.01.10.22; Thu, 21 Jun 2018 01:10:38 -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 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932719AbeFUIJr (ORCPT + 99 others); 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.