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[2620:137:e000::1:20]) by mx.google.com with ESMTP id q2-20020a63bc02000000b00528d0d8b7bbsi10837167pge.595.2023.05.12.22.10.20; Fri, 12 May 2023 22:10:34 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=fail header.i=@mit.edu header.s=outgoing header.b=PbJPQ6ik; spf=pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-ext4-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=mit.edu Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230086AbjEME7o (ORCPT + 99 others); Sat, 13 May 2023 00:59:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229545AbjEME7n (ORCPT ); Sat, 13 May 2023 00:59:43 -0400 Received: from outgoing.mit.edu (outgoing-auth-1.mit.edu [18.9.28.11]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E4719449C for ; Fri, 12 May 2023 21:59:41 -0700 (PDT) Received: from cwcc.thunk.org (pool-173-48-120-46.bstnma.fios.verizon.net [173.48.120.46]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 34D4xX58020075 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sat, 13 May 2023 00:59:34 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mit.edu; s=outgoing; t=1683953975; bh=QIvOIcqpjxYGgMhk21e537adDmqHT5Ejg+fwI5KC/q0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=PbJPQ6ikyC0PryHYsl1TmUqHffgBfXNIq8XXi+Lvw1DpHmKWj0KZIbl8Hi5mJL6y3 Xnx93gBpVOZcBN/v6phddN7nWYsYXQayRMaIdbORs3um5jzcinLmBpws+MmL3SS+gx 3NV5nzjvnSDRPwth9fYEdoWesTpVJGqmhtzIstyci4mgOvM9cWvesxG6JmNN1k7tuT aH8Xw3LjOx2/yR4geDSjYFlIqYtKWppE4WDBwnhpXFCpZpppVRay9rFpAsyCJHeLdi zMpygDDZUHdP69C3lQh05/kSBk0UnAkhnH+N3Qf7eX8tpXW3o6cgBavdmO6gVokO23 g7pmN1ScJ+Y4w== Received: by cwcc.thunk.org (Postfix, from userid 15806) id 75BE915C02E8; Sat, 13 May 2023 00:59:33 -0400 (EDT) From: "Theodore Ts'o" To: Jan Kara Cc: "Theodore Ts'o" , linux-ext4@vger.kernel.org, syzbot+4a03518df1e31b537066@syzkaller.appspotmail.com, Dmitry Vyukov Subject: Re: [PATCH v2] ext4: Fix data races when using cached status extents Date: Sat, 13 May 2023 00:59:29 -0400 Message-Id: <168395396129.1443054.18017236499948982224.b4-ty@mit.edu> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20230504125524.10802-1-jack@suse.cz> References: <20230504125524.10802-1-jack@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-4.0 required=5.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Thu, 04 May 2023 14:55:24 +0200, Jan Kara wrote: > When using cached extent stored in extent status tree in tree->cache_es > another process holding ei->i_es_lock for reading can be racing with us > setting new value of tree->cache_es. If the compiler would decide to > refetch tree->cache_es at an unfortunate moment, it could result in a > bogus in_range() check. Fix the possible race by using READ_ONCE() when > using tree->cache_es only under ei->i_es_lock for reading. > > [...] Applied, thanks! [1/1] ext4: Fix data races when using cached status extents commit: 185e33d15ebf4a9d779fa78249b6cc95a071967e Best regards, -- Theodore Ts'o