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=-13.0 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 47DCDC433E0 for ; Fri, 7 Aug 2020 05:41:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1463020855 for ; Fri, 7 Aug 2020 05:41:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=gmx.net header.i=@gmx.net header.b="YmBX+bV0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725872AbgHGFlJ (ORCPT ); Fri, 7 Aug 2020 01:41:09 -0400 Received: from mout.gmx.net ([212.227.15.18]:35239 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725287AbgHGFlH (ORCPT ); Fri, 7 Aug 2020 01:41:07 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1596778859; bh=LKZrU3qLFV/jzqWhRQVfKpvweGdgfsmTldsEXUaVRkw=; h=X-UI-Sender-Class:Subject:To:Cc:References:From:Date:In-Reply-To; b=YmBX+bV0YRJ5q/O0OBmWlac9NPTnQ/sZP7POzjQ0vW//p3KXPPclXK+MjDmj8JvGN TQuxzea2Rk904FSDI7KJW8rsYit+/oEJKn75jRhKLxfV+pFVSasZMWHo1drOd89EFK jHePbl5olx9wutXWUcFoaQ2nqDBVp7mUepAf1Op0= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [0.0.0.0] ([45.77.180.217]) by mail.gmx.com (mrgmx004 [212.227.17.184]) with ESMTPSA (Nemesis) id 1MVNAr-1kCLYT41Z9-00SRJQ; Fri, 07 Aug 2020 07:40:59 +0200 Subject: Re: [PATCH] btrfs: backref: this patch fixes a null pointer dereference bug. To: Boleyn Su Cc: Chris Mason , Josef Bacik , David Sterba , Boleyn Su , linux-btrfs@vger.kernel.org References: <20200806063144.2119712-1-boleynsu@google.com> <13d20404-ef74-bb04-d206-086207561464@gmx.com> From: Qu Wenruo Autocrypt: addr=quwenruo.btrfs@gmx.com; prefer-encrypt=mutual; keydata= mQENBFnVga8BCACyhFP3ExcTIuB73jDIBA/vSoYcTyysFQzPvez64TUSCv1SgXEByR7fju3o 8RfaWuHCnkkea5luuTZMqfgTXrun2dqNVYDNOV6RIVrc4YuG20yhC1epnV55fJCThqij0MRL 1NxPKXIlEdHvN0Kov3CtWA+R1iNN0RCeVun7rmOrrjBK573aWC5sgP7YsBOLK79H3tmUtz6b 9Imuj0ZyEsa76Xg9PX9Hn2myKj1hfWGS+5og9Va4hrwQC8ipjXik6NKR5GDV+hOZkktU81G5 gkQtGB9jOAYRs86QG/b7PtIlbd3+pppT0gaS+wvwMs8cuNG+Pu6KO1oC4jgdseFLu7NpABEB AAG0IlF1IFdlbnJ1byA8cXV3ZW5ydW8uYnRyZnNAZ214LmNvbT6JAU4EEwEIADgCGwMFCwkI BwIGFQgJCgsCBBYCAwECHgECF4AWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCXZw1oQAKCRDC PZHzoSX+qCY6CACd+mWu3okGwRKXju6bou+7VkqCaHTdyXwWFTsr+/0ly5nUdDtT3yEVggPJ 3VP70wjlrxUjNjFb6iIvGYxiPOrop1NGwGYvQktgRhaIhALG6rPoSSAhGNjwGVRw0km0PlIN D29BTj/lYEk+jVM1YL0QLgAE1AI3krihg/lp/fQT53wLhR8YZIF8ETXbClQG1vJ0cllPuEEv efKxRyiTSjB+PsozSvYWhXsPeJ+KKjFen7ebE5reQTPFzSHctCdPnoR/4jSPlnTlnEvLeqcD ZTuKfQe1gWrPeevQzgCtgBF/WjIOeJs41klnYzC3DymuQlmFubss0jShLOW8eSOOWhLRuQEN BFnVga8BCACqU+th4Esy/c8BnvliFAjAfpzhI1wH76FD1MJPmAhA3DnX5JDORcgaCbPEwhLj 1xlwTgpeT+QfDmGJ5B5BlrrQFZVE1fChEjiJvyiSAO4yQPkrPVYTI7Xj34FnscPj/IrRUUka 68MlHxPtFnAHr25VIuOS41lmYKYNwPNLRz9Ik6DmeTG3WJO2BQRNvXA0pXrJH1fNGSsRb+pK EKHKtL1803x71zQxCwLh+zLP1iXHVM5j8gX9zqupigQR/Cel2XPS44zWcDW8r7B0q1eW4Jrv 0x19p4P923voqn+joIAostyNTUjCeSrUdKth9jcdlam9X2DziA/DHDFfS5eq4fEvABEBAAGJ ATwEGAEIACYCGwwWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCXZw1rgUJCWpOfwAKCRDCPZHz oSX+qFcEB/95cs8cM1OQdE/GgOfCGxwgckMeWyzOR7bkAWW0lDVp2hpgJuxBW/gyfmtBnUai fnggx3EE3ev8HTysZU9q0h+TJwwJKGv6sUc8qcTGFDtavnnl+r6xDUY7A6GvXEsSoCEEynby 72byGeSovfq/4AWGNPBG1L61Exl+gbqfvbECP3ziXnob009+z9I4qXodHSYINfAkZkA523JG ap12LndJeLk3gfWNZfXEWyGnuciRGbqESkhIRav8ootsCIops/SqXm0/k+Kcl4gGUO/iD/T5 oagaDh0QtOd8RWSMwLxwn8uIhpH84Q4X1LadJ5NCgGa6xPP5qqRuiC+9gZqbq4Nj Message-ID: <55450ec5-a49d-2855-0a60-42d8a4d9a8e8@gmx.com> Date: Fri, 7 Aug 2020 13:40:54 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="pU3SaasZi360Ug0wOGFFVBIsKI4ljA2kZ" X-Provags-ID: V03:K1:hIlXktGfqnFP//fZX+Pr1jb8l3aaxtprmG86SKxLOEQ/PN4PI8B BayJAR43TwcEh5RhU6rtIjzqSLpSE8GgtVBwHSvZDaK892dB8k23S1mZ3DtdgMeHSv3XJxk C6edIGsMltlS2NGNA0yHDNYRLXgWW4vtXtWeUj2oejUrHVgqI2S+CBlXMVGAuy1eAvcjXpq wA3ixZm67K+1EXQfuvwmQ== X-UI-Out-Filterresults: notjunk:1;V03:K0:++MHZ9fMiPM=:ilLzizkC2Xstm/CcFUfKb9 EDFDp9fTC+tDLksTJXMEWZ67wv/zKf4MHPnn/bs6q8EhZPXrrrcCpA/c0jyaQg8q6XeVWoz/0 M97xUCRe0JkBEsXLnPtiua1cymqBYAWFxK8W7Kj7Gy45Ftp31FzfCXbJzu79pVzNwXd9RJNDE qPTjJexB+YTrcyYXQ/JJ2FRAHEWYQEZwlhFomRvp/OxTD8bwE5PDYyojd6GL5DyVe9xTs4CcZ bJnv9ljRGe3TwE470xFgnDUr7wup2jy08jas6T493PrLbQwGs9uhfK/nrO7sQR7kpjByWJh8T f8QtwfDGnnjzdzeDw8B1O+jlmrpiWNypZ899hkUP589/+Lfc/TLx1nUoNeS1RK7HVElJrd+pW qBgsh80NQl98KIXYkMt3lsMoWyZFDeVeHhjXB6SQUhbMgnwl/9lLBRvh3lrakL84fdSCnrr1g gtANTzoGnfmwwAsdVMTM6UnwXJp0EPxTdEis0gVuc4qsB65L0jU6aT7wn9KEC0K3MEjiPQQbm Kczig4ejFwjgw4hG07YkRYgNF+qRwsLqP0VRmPDi+aPOn7x/8MYQ+4upUeL9ilbZL+c+TFjTQ 2rrQN9VCR0WqGoCtSXk5Mwp0H4VhY4x1jgDM5Ssbp6dUt2sgQ6le0djx8JPo0pjvtZMfz4lBf MxGPY96jcRcSRRUvBnzWzwzbg/v6Mwv52V5xZzOOv7/o3WEXaeif1aDwr64l9eLr8aBW/CA9s C0rs3pKhdiV2MI9OusE7XRjncaMiokkODfnzG5JdGAnuMXA1FQJbMccUI1utzvcdERms8Kwwn PD7/A2XtxxYmOm8t1JxGN5xNhW/QsJJBZx4wNYGaadF8CvOHbgkJVz5cFSbqGmv9dU0KdJGMa Gh1bD8emNUqdVqJ0kZGxOjQwoBsuq54Qj9d3wd4CWjQZwuTl/Cd73+lPr5n5VzxvtV2HMd2/9 gzfH2DI2YZNWaCBaXesYS6C2o5v8DDDfm2vHD4IP/aBMT/LOmXr0x1B+C9NN8UARdcAHZ9JC5 Tfet66hcQOLtyNHtM2FypGWT2+LBIRA14yE7Xn+k7LLzuUGUKzHrlyyIpudrUqk0SZxeAe2sB K5YIuyQ+6UR4zSthldD0Z8X5IhwPg7hFA2ro4C6ltp+qm4IwMKcB1l2PF6BT88JF4fpyP3wNY lbZ7Yq66SjJNWGP6/VzqbI82yGwTxgwPmWM+OXmDNj02H6LBgbbVTNRKrc4RmiqNesLbRS2t1 Kt584XJuHZFSsJaKD3gZ4y549bxgqDo6LFQOI8A== Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --pU3SaasZi360Ug0wOGFFVBIsKI4ljA2kZ Content-Type: multipart/mixed; boundary="K4JhHNLpPTSdx3BTDbdN2k5MF3p0DddtQ" --K4JhHNLpPTSdx3BTDbdN2k5MF3p0DddtQ Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 2020/8/7 =E4=B8=8A=E5=8D=8811:34, Boleyn Su wrote: > Thanks for the review. BTW, do I need to do anything else or just leave= > it to you? > If you mean adding the extra reviewed-by tags, no. It's handled by the awesome maintainer David. But if you mean to find more btrfs bugs, then keep going your awesome wor= k! Thanks, Qu > On Thu, Aug 6, 2020 at 4:04 PM Qu Wenruo > wrote: >=20 >=20 >=20 > On 2020/8/6 =E4=B8=8B=E5=8D=882:31, Boleyn Su wrote: > > The `if (!ret)` check will always be false and it may result in > ret->path > > being dereferenced while it is a null pointer. > > > > Fixes: a37f232b7b65 ("btrfs: backref: introduce the skeleton of > btrfs_backref_iter") > > Cc: Chris Mason > > > Cc: Josef Bacik > > > Cc: David Sterba > > > Cc: Boleyn Su > > > Cc: linux-btrfs@vger.kernel.org > > Signed-off-by: Boleyn Su > >=20 > Nice catch. >=20 > Reviewed-by: Qu Wenruo > >=20 > Thanks, > Qu > > --- > >=C2=A0 fs/btrfs/backref.c | 2 +- > >=C2=A0 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c > > index ea10f7bc9..ea1c28ccb 100644 > > --- a/fs/btrfs/backref.c > > +++ b/fs/btrfs/backref.c > > @@ -2303,7 +2303,7 @@ struct btrfs_backref_iter > *btrfs_backref_iter_alloc( > >=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0return NULL= ; > >=C2=A0 > >=C2=A0 =C2=A0 =C2=A0 =C2=A0ret->path =3D btrfs_alloc_path(); > > -=C2=A0 =C2=A0 =C2=A0if (!ret) { > > +=C2=A0 =C2=A0 =C2=A0if (!ret->path) { > >=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0kfree(ret);= > >=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0return NULL= ; > >=C2=A0 =C2=A0 =C2=A0 =C2=A0} > > >=20 >=20 >=20 > --=20 > Boleyn Su (simplified Chinese: =E8=8B=8F=E8=95=89; traditional Chinese:= =E8=98=87=E8=95=89; Pinyin: > S=C5=AB Ji=C4=81o; Katakana: =E3=82=B9=E3=83=BC=E3=82=B8=E3=83=A3=E3=82= =AA) >=20 > My PGP public key is available at=C2=A0boleyn.su/pgp . --K4JhHNLpPTSdx3BTDbdN2k5MF3p0DddtQ-- --pU3SaasZi360Ug0wOGFFVBIsKI4ljA2kZ Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEELd9y5aWlW6idqkLhwj2R86El/qgFAl8s6WYACgkQwj2R86El /qgz3wf+JQlL4BRIWHV8JJQRzoSz2T6wqgQMaDxgP5KTcUANeSkP+6NvfvwfFaeQ XMvMHt29XJx324yIgNNmvTr4484EchMGJ3U5jX7EnvTVQnfjY332m1ZQjgNaETOe P9gqajDQBvuAb4LcjA0Wa2sQWjhmZMZsGy/N1RlGpMMMu2tqbJuB4enK/1usdHJn DkeXdlbMKItq3rwxQc5msBMnI6lAylscI3aicM/UT6fXfJDXDNnC63+lN9YBfCEQ ymjTcea2p6jFG51IGVoyd3miCnSBY4fyYTElWs/cuet5RRyhjiV/5t++nxJe/u0e YEVw8AIEyjWYzct0QzKsmStdmWSfNg== =3QyV -----END PGP SIGNATURE----- --pU3SaasZi360Ug0wOGFFVBIsKI4ljA2kZ--