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=-1.0 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 483A2C43219 for ; Mon, 29 Apr 2019 18:04:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 16BE92087B for ; Mon, 29 Apr 2019 18:04:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728903AbfD2SEf (ORCPT ); Mon, 29 Apr 2019 14:04:35 -0400 Received: from mail-pl1-f194.google.com ([209.85.214.194]:35446 "EHLO mail-pl1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728748AbfD2SEf (ORCPT ); Mon, 29 Apr 2019 14:04:35 -0400 Received: by mail-pl1-f194.google.com with SMTP id w24so5454478plp.2 for ; Mon, 29 Apr 2019 11:04:35 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:subject:from:to:cc:date:in-reply-to :references:mime-version:content-transfer-encoding; bh=xFE02sFeAUQCKTOBLpVSCOCSjZU6ktmDtPm6wqRAMtY=; b=bfDieX7A0j3k24VZWe/I+hkqpwcPJYa/2qFDQdF1d/cLGblZj0STB2xtkhrZORA6Ob H5t+rRJnbBpe+TqTUT3ldPGetEfIzPvle4OAfyxneEjX1jLQBqZL5zQO3AxPj6ixIYPa RKbUc+rpmHcczIH3rU5OZfnl/LUHii4juV0c45SP2gm2B5sCdHyPByiPSQmS37KVKWjM 7TW4sfacBb8uH3h2kDP+13xq6v43SSqRCxb/oHd45uCER5McD+nLAV3DGpVqkGYgj5x7 MFm1FE0m6FgaVcW31M/Jja5+4DJ1e4822ZWxN92BIWY4ei5gMLfD1SdtA7NzjunGVhEK bsCQ== X-Gm-Message-State: APjAAAVqQEAB7bjSt/Im0ns8gQkHmUnDFY/pWsbz66gvLen9YuT8Vhhs 6Hgn4gRnj8XoIOI+AHRzANI= X-Google-Smtp-Source: APXvYqwqQf2tV3/q7xu4rTuT0bB+6DXN5KJVlewuQCS5hRteEUHCZw3+ujva9234bmERfw+9rS+dyw== X-Received: by 2002:a17:902:e785:: with SMTP id cp5mr3273795plb.43.1556561074247; Mon, 29 Apr 2019 11:04:34 -0700 (PDT) Received: from ?IPv6:2620:15c:2cd:203:5cdc:422c:7b28:ebb5? ([2620:15c:2cd:203:5cdc:422c:7b28:ebb5]) by smtp.gmail.com with ESMTPSA id w189sm66275827pfw.147.2019.04.29.11.04.33 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 29 Apr 2019 11:04:33 -0700 (PDT) Message-ID: <1556561072.161891.159.camel@acm.org> Subject: Re: [PATCH v4] blk-mq: fix hang caused by freeze/unfreeze sequence From: Bart Van Assche To: Bob Liu , axboe@kernel.dk Cc: linux-block@vger.kernel.org, hare@suse.com, ming.lei@redhat.com, hch@lst.de, martin.petersen@oracle.com, jinpuwang@gmail.com, rpenyaev@suse.de Date: Mon, 29 Apr 2019 11:04:32 -0700 In-Reply-To: <20190425102846.28911-1-bob.liu@oracle.com> References: <20190425102846.28911-1-bob.liu@oracle.com> Content-Type: text/plain; charset="UTF-7" X-Mailer: Evolution 3.26.2-1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Thu, 2019-04-25 at 03:28 -0700, Bob Liu wrote: +AD4 The following is a description of a hang in blk+AF8-mq+AF8-freeze+AF8-queue+AF8-wait(). +AD4 The hang happens on attempting to freeze a queue while another task does +AD4 queue unfreeze. Reviewed-by: Bart Van Assche +ADw-bvanassche+AEA-acm.org+AD4