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=-2.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 3ABC1C43331 for ; Thu, 2 Apr 2020 15:19:05 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0C9612072E for ; Thu, 2 Apr 2020 15:19:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Yev72oAq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0C9612072E 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-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=aWcSx5w7j4rS4V9Mk3EtAZJTqKKUWFUsdnJdyw137ms=; b=Yev72oAqrk/J/Z uS+9R2cNUb/ynIBEbsceqZ2fbt21/FvB27HbrKQnLZxWBBBq6F78hv4nIItG5yQOD/3TehJzE0lKS y7k0ZavC+LPdOQyod7uwOUOaySAnZK7qNBEhTPb5lYdwERAzZDUN/GGbeujCU4DAUAOkWyxtR+bqF YjU/cDIdB3jbF+NGan0n1EUfwnDNFWrFg/cVhdTKjCzmlYOm4f7N3V4eZsraxVXsgsY/xyLiy76Dt s1wFd20QQoSr2Ii6VMxFjFssmbwyLz9f3i1ej3G5UY1GIX9Y2ZuVs909ZbgagGoDbnU5yCiZuCIdu RO0QfXmzgGjl7wOeMmWg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jK1cU-0005D3-3L; Thu, 02 Apr 2020 15:19:02 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jK1cP-00054v-V3 for linux-nvme@lists.infradead.org; Thu, 02 Apr 2020 15:18:59 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 9D6B068B05; Thu, 2 Apr 2020 17:18:54 +0200 (CEST) Date: Thu, 2 Apr 2020 17:18:54 +0200 From: Christoph Hellwig To: Sagi Grimberg Subject: Re: nvme deadlock with ANA Message-ID: <20200402151854.GA11784@lst.de> References: <5e38c566-3f26-288d-1004-161d1084b468@grimberg.me> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <5e38c566-3f26-288d-1004-161d1084b468@grimberg.me> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200402_081858_183976_2F49B314 X-CRM114-Status: GOOD ( 12.39 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Keith Busch , Anton Eidelman , Christoph Hellwig , linux-nvme , Hannes Reinecke Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Wed, Mar 25, 2020 at 11:23:50PM -0700, Sagi Grimberg wrote: > Hey, > > I want to consult with you guys on a deadlock condition I'm able to > hit with a test that incorporate controller reconnect, ana updates > and live I/O with timeouts. > > This is true for NVMe/TCP, but can also happen in rdma or pci drivers as > well. > > The deadlock combines 4 flows in parallel: > - ns scanning (triggered from reconnect) > - request timeout > - ANA update (triggered from reconnect) > - FS I/O coming into the mpath device > > (1) ns scanning triggers disk revalidation -> update disk info -> > freeze queue -> but blocked, why? What does -> but blocked mean? > > > > (2) timeout handler reference the g_usage_counter - > but blocks in > the timeout handler, why? The timeout handler obviously needs to keep the queue alive while running. We could think of doing a try_get, though? _______________________________________________ linux-nvme mailing list linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme