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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 703B0C433EF for ; Wed, 15 Jun 2022 21:27:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349781AbiFOV1o (ORCPT ); Wed, 15 Jun 2022 17:27:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50862 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349710AbiFOV1l (ORCPT ); Wed, 15 Jun 2022 17:27:41 -0400 Received: from mout.gmx.net (mout.gmx.net [212.227.17.21]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 65BFC167C7; Wed, 15 Jun 2022 14:27:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1655328434; bh=sewS1k19E5zNFt7guGx8ADD0uovsZroqX/MykOeNoAw=; h=X-UI-Sender-Class:Date:Subject:To:Cc:References:From:In-Reply-To; b=ZaY29LgSeKsC0VKC0SfEO8gCT/mbD6Qy/5eG//rKUlfwQK32wCZyAB8p4+MeiczAs wEnfd+sTmcT94yqzlRVJePYywnp5EvPECoxAhy5pRe56snX/8JFtBBgpCsKSUAfHNV jL/7QpKzQmAvk0RCH/rLb4FqlMv8n1jXIqjxFB38= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [0.0.0.0] ([149.28.201.231]) by mail.gmx.net (mrgmx105 [212.227.17.174]) with ESMTPSA (Nemesis) id 1MsHru-1nhIVP2ZLu-00tnF1; Wed, 15 Jun 2022 23:27:14 +0200 Message-ID: <00bbda63-dc00-05c0-4244-343352591d98@gmx.com> Date: Thu, 16 Jun 2022 05:27:04 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.10.0 Subject: Re: [syzbot] KASAN: use-after-free Read in copy_page_from_iter_atomic (2) Content-Language: en-US To: Christoph Hellwig Cc: dsterba@suse.cz, syzbot , akpm@linux-foundation.org, clm@fb.com, dsterba@suse.com, josef@toxicpanda.com, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com, willy@infradead.org References: <0000000000003ce9d105e0db53c8@google.com> <00000000000085068105e112a117@google.com> <20220613193912.GI20633@twin.jikos.cz> <20220614071757.GA1207@lst.de> <2cc67037-cf90-cca2-1655-46b92b43eba8@gmx.com> <20220615132147.GA18252@lst.de> From: Qu Wenruo In-Reply-To: <20220615132147.GA18252@lst.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:GzvWUv7j+dS6fGBh0O76pQHRuv0QctvPBDKfUco4+Y/GlL/5y5g BXHYTJT9fnyYxlKhn1+btWdWvWOiF9BDnLfCq+EChmasKSAq6b9B1pCQq6ZQASuejlOodGV HN32edj0jLN7bwq3m5m0D0pObpIh6RNHWquJ644IBNrDdnIdMTXGq0sbFfGfNtFwiDuTyIw bbtKn1jfl54A+36cVRM4w== X-UI-Out-Filterresults: notjunk:1;V03:K0:lmKkDBBaQN4=:jf9gSILfZGEkHNseXPaNRe PvP7u+k40FY2CY2c0qVJJZBB/SSwTJDnZaUJ+SDpqeZrdOVsk4C8rtHyoZ8VARRoOxw5VTHmO Ccz1d/+zDolUMSDJN/JxkTSUDCi2OKfQeM8YN7zQyU1v+Pg8h/hVzRfH+sXiLqZHpm7yImcXe Zns22cRY5ahuRaE2oWaY1UC1+UNPve57Dv7F1pFGJQVGEqTOvkI1xzJuM8qT/ieBd55fD/oAs +55imKkenFxKoBNFuRBqJtrb98zaAbF0NbNBl5pktTcEOsz1cjYh4KKWMFNa5qnu3lHRVjFW3 ONRUrJDpOunQSHpCP8sruk9PrSwAmxUHeIWZdGTY7XIfJUMs/ISyhdsYDW1cMmK2JGnUtyp0q /5fzm0FFf6xdr6G9q4cwF1q2jsuHIV+y7uKkqGyNicAXak9LPk7aXkU6Mnw0WYUKFdBmMPYTJ 8TvJRrLCXnJB4RQGlAe2KNe3jelUpxv0Ei6DJqn7gTb5tiESBPwTu7NHZ7EcZ+io2rjhfrJ7y Y/FP/JpHG1b//XFXHUbQTCvbMJ/43T/wrLGtw3wwa2RDgtWGdP+XwIGL5sAlQODdEKXMR2hxa L6yL2jOirN64cSOHfNuQ5aHJ9fhfqmezh1imJwI7+nWdkjiKYZMgucyVWFqTwZAyclAj4jLka eSVL2A07OUVdeB6IDpq4LW4KFqX+HFtZD566Dw61X8vjl4W2kSyTdZknPV/eatpzAEQKJ+YA3 +wvPTCK/09H35naTvpU8cdM9FDkWK2rEQHZZpBSlCC0D6F+x3GT0XL2fj+v9j+51RUk2Q4Hbc ByLPN/HiArHr1xbq6ktyJEjpMmjMQMv30Vq/4BM6ZqJty8OHCs7dnwqBo1RxgcaDcglFBAy6r Wwsy3UqRjM3N3/IsstSmsF1f112zJKzsOYGBVU4n+YxJgSKiRC7yDB2VPVt3e6jdeK3Y8m5gg qq53Pz/u7c4wKhvf5ASPAnB2ygA748E+2SLwxVHmnm0UFKhZJCJA+GnZsL21qOCyZ6N0bei8M QRln+yhh05sPLbVNlsPEmewJAHICI57FsNDrKog79AJsQEEtviKYHZqb1O8GsrBevAn4KBoZi Xr+vzv/l0huLKyq0FCz7buQROHIxWvDxZDm22i6sWCwe/AwVl79didzmQ== Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/6/15 21:21, Christoph Hellwig wrote: > On Tue, Jun 14, 2022 at 04:50:22PM +0800, Qu Wenruo wrote: >> The same way as data? >> >> map-logical to find the location of a mirror, write 4 bytes of zero int= o >> the location, then call it a day. >> >> Although for metadata, you may want to choose a metadata that would >> definitely get read. >> Thus tree root is a good candidate. > > And how do I find out the logic address of the tree root? For tree root, "btrfs ins dump-super | grep '^root\s'. For other tree blocks, "btrfs ins dump-tree " then with other other keywords to grab. Thanks, Qu