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=-5.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, 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 2E904C433B4 for ; Sat, 24 Apr 2021 19:33:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EE0CA613C1 for ; Sat, 24 Apr 2021 19:33:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232546AbhDXTeE (ORCPT ); Sat, 24 Apr 2021 15:34:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52178 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232539AbhDXTeD (ORCPT ); Sat, 24 Apr 2021 15:34:03 -0400 Received: from mail-pj1-x1034.google.com (mail-pj1-x1034.google.com [IPv6:2607:f8b0:4864:20::1034]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D0FB4C061574 for ; Sat, 24 Apr 2021 12:33:23 -0700 (PDT) Received: by mail-pj1-x1034.google.com with SMTP id s14so19935074pjl.5 for ; Sat, 24 Apr 2021 12:33:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=rO/BU/4BwTXgn/LS1reLpKHsO8KV0oaUU7jrX6j9d+Y=; b=xu9m91DVUffZdKC2kADmzjrVOUxIpf9enSpUL3Vcda9GVCGFWoFchoGvsHB3m2cLpZ srFbNMIDW03Z056iX00n+4WtXrb1vBkyXQ+3q1qAx0lxDBMfe1TyDAznfG2IZWbXr1kp Bd4Na5VcUfQGVGU6eso7Uuf4CxOhWSPjZSabnlZWm8o3OpU/FA2uAewDfaoADOdiIahU s8jt5fcF2YHP5ea1Qo6hhEK4ciPxywqTF2jWqn699Tk7lNwiyYFwr1FOZ+bj0ettbgsB KQXMyCnlHybvAoCdOjT6PdtpMsR8bRnBOd4owT3/8+kw12p1y8JiXrr956umPNH5j5qM vCDg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=rO/BU/4BwTXgn/LS1reLpKHsO8KV0oaUU7jrX6j9d+Y=; b=alfJNjD+kpvtodjLmu+zP8ApdVB3gx1NCY4rwIL3WrIlNgZpicVKPMXyQBgMT1PM45 aa9Xd0B9kqgyWFcJQ87ro1IaFHWbPNCBTbUdzcg8ANVgT7nTzG0QACvA1AOyZQGi4fns o/gg83q66xIaBW5sCq4A7O6tLzBfeMs55vmM01gB7bDSSTs6EH+CpWJd5gsvKxbVx9gR v4WYf4COgMzsAiLd/gNBESIrZ6lquiHW3LHbu+RbY0AHe9Htp+2Y3E+9md4lzEb4TKmU FyAozohCytz2oE4i48Ckc5UfCdrRzbjRAyyLSvUvIGSCPSnCltUkOPoSLzRt1xgQzLu2 RcZg== X-Gm-Message-State: AOAM530IWgDxYokhbb2g2AoOC6OwqPiKfyUL5k9XDfjyYqzhKV6Sb3N3 0Tc/+ZZ/PWXYrk4AsM16gOjhZg== X-Google-Smtp-Source: ABdhPJz7X3Xz1yT2zeyxxOJWIAIwHXbeDV+S2TCOv5iLmiJS65zkkODzeNlMUN+Qgw3UNiAIm9RGBg== X-Received: by 2002:a17:902:b494:b029:e7:36be:9ce7 with SMTP id y20-20020a170902b494b02900e736be9ce7mr10299248plr.43.1619292803026; Sat, 24 Apr 2021 12:33:23 -0700 (PDT) Received: from [192.168.1.134] ([66.219.217.173]) by smtp.gmail.com with ESMTPSA id f5sm7507630pfd.62.2021.04.24.12.33.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 24 Apr 2021 12:33:22 -0700 (PDT) Subject: Re: [PATCH] blk-mq: Fix two racy hctx->tags->rqs[] assignments To: Bart Van Assche Cc: linux-block@vger.kernel.org, Christoph Hellwig , Ming Lei , Hannes Reinecke , John Garry References: <20210423200109.18430-1-bvanassche@acm.org> From: Jens Axboe Message-ID: <661306fd-0adc-dff7-c79b-f4be8feba73d@kernel.dk> Date: Sat, 24 Apr 2021 13:33:21 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210423200109.18430-1-bvanassche@acm.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 4/23/21 2:01 PM, Bart Van Assche wrote: > hctx->tags->rqs[] must be cleared before releasing a request tag because > otherwise clearing that pointer races with the following assignment in > blk_mq_get_driver_tag(): > > rcu_assign_pointer(hctx->tags->rqs[rq->tag], rq); Looks good to me. Applied, and added: Fixes: 5ba3f5a6ca7e ("blk-mq: Fix races between iterating over requests and freeing requests") which was missing. -- Jens Axboe