Received: by 2002:a05:6a10:17d3:0:0:0:0 with SMTP id hz19csp839903pxb; Thu, 15 Apr 2021 07:49:56 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyIBbgCJUKJe9hR9AbUwEUidpJwwYkmKBmzVgoBj9jaRo8NZVQlangLVJK6dkNVtOJuezT5 X-Received: by 2002:a17:90b:46d7:: with SMTP id jx23mr4150967pjb.168.1618498196652; Thu, 15 Apr 2021 07:49:56 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1618498196; cv=none; d=google.com; s=arc-20160816; b=dgAVwAAFZUkJg7K2U/hsexzlfxx21dBjP1fGiHjoZWJJAh81KomlzN+SgB9pyJCGRl ZMAqAjXZq8mXKNih1ZD8rvzhIgCklS0v8JrnWXBrMEO2Q7tZ3ZqZZbOsZomjek212yEz kEtUFiGa9vfhN5NdwguqNyw1V0HyYyssKt6xOoTyZ9/W0V89/0GrdzZTa0jY44+Cav1B QnvrcUuUahESVOOLrVTA6RhlLrJrIU4gISEHQEJ9xuzJj587JTQzQ5zv0FCzoA7SR5Hy n3yKKb6A9bH7cM/vbBYUZELmZ2fNIkB26OFBzbSDJoi/LUizl2WYE33Ibsri/DCGBhqU HsuQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:in-reply-to:content-disposition:mime-version :references:message-id:subject:cc:to:from:date:dkim-signature; bh=Z7+Tu/cOwOD4zUSujDMlZ1cKk6U8IueYF+2Nrcr7Rpk=; b=E5OJEnU/PgGq9xa+ctiLJqZjxNQYDqE6der1IDICoQm6QFF8TLx1nwj61bu/qv9ZeT +IxrISID19uYyCm6MkNHEs1Utc/Yq/kmh+yDgkabvdxPCuK8DQZfUf12SXIW4dqw4APU IPVmIAyuDY8lPUcL2Y2wB2BSHyLp6V+o4f87uthEep3jbXFFfNSMdDFZ0oeOiPQ2cGan a0KWWEx8LMw71yMHXA85AzXSGhwDiRRQl6Db+xp53eB8aZahHWbQ7wpTcSDpAD4jd1RP YogBB4F9uE+noNr0Y7KdqroxfFwj8NXMPsLkBATezZaxjNiyUdRby/xDtX7N7uFggwAk a0PQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@infradead.org header.s=casper.20170209 header.b=R5h6S1ty; spf=pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-ext4-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id h17si3436570pfc.290.2021.04.15.07.49.43; Thu, 15 Apr 2021 07:49:56 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=casper.20170209 header.b=R5h6S1ty; spf=pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-ext4-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233757AbhDOOto (ORCPT + 99 others); Thu, 15 Apr 2021 10:49:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42902 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233728AbhDOOte (ORCPT ); Thu, 15 Apr 2021 10:49:34 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C1B9AC061574; Thu, 15 Apr 2021 07:49:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=Z7+Tu/cOwOD4zUSujDMlZ1cKk6U8IueYF+2Nrcr7Rpk=; b=R5h6S1tyNmZbHxJvdQgMubPVSB DTeZTGp1jMPNCG0srQBvRf+z0qDzeG4yVZj/KEy6gqRkwlPpujWI6LRwf2My5VNizUenOYZ9Mu9KG 6FQDSkVfGGPlZN5wGXoj40L8fG+exL/JDAoCxDYwhsB2JIcql7FSgO766mvQVk4dzW5TD/u7OzRH8 c83AR1fS2V70km5x4DZTmO04ZLm94DTw9sI/cI1h0Zve2oMbKR1xWKIzYn7Q5D+B6dHtdBqjW8rhg RAPUJSwr8vHM6AeCu3bSjrzc4yrSio1uZk3EqegbTrSqL9vR47nMz87XwyVqlWxVyYzzLj7W0D21J QM6z7T0Q==; Received: from hch by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lX3ID-008gt0-EE; Thu, 15 Apr 2021 14:48:36 +0000 Date: Thu, 15 Apr 2021 15:48:29 +0100 From: Christoph Hellwig To: Zhang Yi Cc: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, tytso@mit.edu, adilger.kernel@dilger.ca, jack@suse.cz, yukuai3@huawei.com Subject: Re: [RFC PATCH v2 5/7] ext4: use RCU to protect accessing superblock in blkdev_releasepage() Message-ID: <20210415144829.GC2069063@infradead.org> References: <20210414134737.2366971-1-yi.zhang@huawei.com> <20210414134737.2366971-6-yi.zhang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210414134737.2366971-6-yi.zhang@huawei.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Wed, Apr 14, 2021 at 09:47:35PM +0800, Zhang Yi wrote: > In blkdev_releasepage() we access the superblock structure directly, it > could be raced by umount filesystem on destroy superblock in put_super(), > and end up triggering a use after free issue. The subject is wrong, this does not change ext4 code.