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=-10.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 E3E95C433DB for ; Tue, 16 Mar 2021 06:19:08 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 6CA826501D for ; Tue, 16 Mar 2021 06:19:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6CA826501D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com 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=desiato.20200630; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Cc:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Yh7JV8w6TjXcbhcttFdLW9GstZuG0JSVRo6ZYJ2k3Lc=; b=cHOueoIJ63lj7+tEAMeiqtdzS QtvshAmt3CwYfKiDi4Hk3e1gk8md2l/cXAScdoXhmLrMuQTEylIkLHJpTu2u84s0/grwOJFf2J2IZ Kk92IL/KKqFCUs6SKv04JYNAESSFK28+B7xH1ZzLWMNYKsl8f7FcuUEY0GBX9q+38XWAAuLB3kkpt OL7gzh65AvKWaG46KPu+wc3m5ipz66V7pAlJn3XH4HcvF0D4Y7m7J5rOxWnptIQKqDV4Z4ksmx2KW fJg8WXNqLnUSVgeOpcxcIeZ84Y/YeiESyVMeQK+DzuN7WaxdC+N5JpuJtm4kWswYgpShk/MqV+I6k B6kAGtYFA==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lM32Q-00HVxK-T4; Tue, 16 Mar 2021 06:18:42 +0000 Received: from szxga01-in.huawei.com ([45.249.212.187]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lM32K-00HVwf-Ul for linux-nvme@lists.infradead.org; Tue, 16 Mar 2021 06:18:40 +0000 Received: from DGGEMM405-HUB.china.huawei.com (unknown [172.30.72.57]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4F031Y5N9VzWLTn; Tue, 16 Mar 2021 14:15:29 +0800 (CST) Received: from dggema772-chm.china.huawei.com (10.1.198.214) by DGGEMM405-HUB.china.huawei.com (10.3.20.213) with Microsoft SMTP Server (TLS) id 14.3.498.0; Tue, 16 Mar 2021 14:18:29 +0800 Received: from [10.169.42.93] (10.169.42.93) by dggema772-chm.china.huawei.com (10.1.198.214) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2106.2; Tue, 16 Mar 2021 14:18:29 +0800 Subject: Re: [PATCH 0/3 rfc] Fix nvme-tcp and nvme-rdma controller reset hangs To: Sagi Grimberg , , Christoph Hellwig , Keith Busch , "Chaitanya Kulkarni" References: <20210315222714.378417-1-sagi@grimberg.me> <7d552635-6f95-fca4-b0ca-709967465495@huawei.com> <3a172ebf-eeb8-b7a0-4eb2-099fa74bc1c6@grimberg.me> From: Chao Leng Message-ID: Date: Tue, 16 Mar 2021 14:18:29 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <3a172ebf-eeb8-b7a0-4eb2-099fa74bc1c6@grimberg.me> Content-Language: en-US X-Originating-IP: [10.169.42.93] X-ClientProxiedBy: dggeme702-chm.china.huawei.com (10.1.199.98) To dggema772-chm.china.huawei.com (10.1.198.214) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210316_061838_019792_46E602A1 X-CRM114-Status: GOOD ( 17.18 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On 2021/3/16 13:04, Sagi Grimberg wrote: > >> Does the problem exist on the latest version? > > This was seen on 5.4 stable, not upstream but nothing prevents > this from happening in upstream code. > >> >> We also found Similar deadlocks in the older version. >> However, with the latest code, it do not block grabbing the nshead srcu >> when ctrl is freezed. >> related patches: >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/block/blk-core.c?id=fe2008640ae36e3920cf41507a84fb5d3227435a >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5a6c35f9af416114588298aa7a90b15bbed15a41 >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/block/blk-core.c?id=ed00aabd5eb9fb44d6aff1173234a2e911b9fead >> I am not sure they are the same problem. > > Its not the same problem. > > When we teardown the io queues, we freeze the namespaces request queues. > This means that concurrent mpath submit_bio calls can now block with > the srcu lock taken.What is the call trace of ->submit_bio()? The requeue work or normal submit bio? > > When another path calls nvme_mpath_set_live, it needs to wait for > the srcu to sync before kicking the requeue work (to make sure > the updated current_path is visible). > > And this is where the hang is, the only thing that will free it > is if the offending controller reconnects (and unfreeze the queue) > or it will disconnect (automatically or manually). Both can take > a very long time or even forever in some cases. > . _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme