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=-5.5 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 B3918C433E1 for ; Thu, 16 Jul 2020 00:15:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7500C20658 for ; Thu, 16 Jul 2020 00:15:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=gmx.net header.i=@gmx.net header.b="AUaLWZTi" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726945AbgGPAPT (ORCPT ); Wed, 15 Jul 2020 20:15:19 -0400 Received: from mout.gmx.net ([212.227.15.15]:52087 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726479AbgGPAPT (ORCPT ); Wed, 15 Jul 2020 20:15:19 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1594858512; bh=S/oRe9zBudJ+a06ninXBZ8EZe9AIIxVE+8Rbt/sdpEY=; h=X-UI-Sender-Class:Subject:To:Cc:References:From:Date:In-Reply-To; b=AUaLWZTiu8ySY3jx0/63i55Dii5oY1l1C/wemFnvpmZ6KlWTKICpP9MabH1zIgd9h 8OxgT/QZT3rnxuoTNykSXQBzjw1I/JVEvlezdYyX56MZ2+vkAHNJZUkND2G+cjxrAL 284fgsSpnFcbcY4SIL5TlGgIH1jstJ/RAwna+n4Y= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [0.0.0.0] ([149.28.201.231]) by mail.gmx.com (mrgmx005 [212.227.17.184]) with ESMTPSA (Nemesis) id 1Mj8mV-1kXvb83jWv-00f8sg; Thu, 16 Jul 2020 02:15:12 +0200 Subject: Re: [PATCH v2 2/2] btrfs: qgroup: add sysfs interface for debug To: Chris Down , Qu Wenruo Cc: linux-btrfs@vger.kernel.org, kernel-team@fb.com References: <20200715134931.GA2140@chrisdown.name> 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: Date: Thu, 16 Jul 2020 08:15:08 +0800 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: <20200715134931.GA2140@chrisdown.name> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="vkE7UOlaGx0P74iBgXS0rx8SU5D6UI2qR" X-Provags-ID: V03:K1:BToiSrHAYhUhDxcMs0h/OzHrjiLAzpl4GvnRDm8L0qowcYJg4Ft Bh6vcUx9OmQGw/TX9j/yxfdTIcptfYJmR1srJ7j/UY/R4bd26xMWZoC+P9pESz1K89/gKO5 aTTtzytqpoFp3FCJbuSJ5mGcPY54a9KL69FAvx9SCJvZj9TIPk3W9dgGkpUle5NCDt2gUe9 B/xoAOep5OtSElrPRGgbw== X-UI-Out-Filterresults: notjunk:1;V03:K0:87eUFBhNzDE=:ZhCfdkzQ9/OSalJqyexAev oZEvIRW7aa9phCNP5X2qnffajiF57QfqqPFn6G4vPVkT+2UQsAeLoRGb4HFn7QfppdYOkDYJa +Ua2ThLU2pVPr2H2Unm8xQgIKF0dUuMvyZHrR+zGNznfcbq2icmQE6JAUa2AW3js+5EtP82pE V0asxzNRGHEgdsq/hNTMG9g1JZOTuRu1ZVPzc2ApCit2+dVYpSh1/yFPD51RBoSaEWo+vaAe9 5wp8hRm0BT/e8PGZZlkXHm5+Uyg9TBi0JaTG+frgGLwOe775CRymzZwxBcB7rxJGYPl/As6XD 6A8Cl9vdOKjkexMds2eJxY7WjWhetA0fPJsGr9CcRzv/K70NJJvzrq/nzf1hR120yvwdwrXEh yldTvyILYJkLjkBMww/Fry/0H9F2ecXjkmOvy6aVWJDfcKJGK0bArwZ0A8TuqzJfJKxaao8Yp zdVili7xISm7ELbcl6QNtCJ7l7Ittd56aaoLzRiKbEI6yBHIIl9/sSjigcNvpjKHhoYOYgK68 26VPcdCw7ypZnBab4qfBfhHiMnW8ILebhYlaoNi9uHy4VAQ1ZOo67fzx/LV1MxxOfQhdBjUAq rxeIooKqsebgll3Vz4A9atb93zhv2IPCy3cL0nN2VdhsP+gEKkRspjfxv7aJIVVKs1U5vK20E n3oITGHp9itRCm7vpwVeuzD8eX6L3+PvhYmr30rfy9veovLhWEWXHgopYeRJnk2uSMOOHuChU ud6GDsHqEyCrDjlCVSEVUEarGwE5prMhaT78y+51a3TuiDJWMNB3BrSi21svqTHeBauzmTxHq RyAj8WuQM7ZHMm111MFTEZvr5nK74D2xVM/M/xq2Zy8qxcrbKEqXqzmxRCwzB8t4mzMOg6qLf cDCXQ2kztb7qNIUEOIUmPrZkSKaVDR72ZNM9S86LKgBexKJLVZJVQ7lM5wmSd4/g7dgpT/ndo mU8u1yEauKZYLu35v7Kit9HPL3EOwAspywclJqt1YJi/6v37+Pyj0HXWQxur/dG+vJTnfY9JO bJgkN7JyHylxM7QIEZZXvf4A02RK2a0A+3FtGI7IVQWE30IHA8EM+VleL94aGNXhY79l38Yqa XOhHMZrgQTaiIFsvB43KjGtnFe3NCz4xpuQ7GW8FLfvNAiIBT0W1/CZaotfHdrlxMHzVNH0LT dPs37hyL3duVIxTN/LWIzGo/zVbL3xoDnrvzjF+vfuoPsy01TK5o6Aj2+bRyrXfDoRyby8Ots vXC62LQfeIfBEVCdWmkw+npnpBx9lp0M6mCanhw== 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) --vkE7UOlaGx0P74iBgXS0rx8SU5D6UI2qR Content-Type: multipart/mixed; boundary="jV1jsiF3t3CAM4fbGg56H118rgUfEzDkB" --jV1jsiF3t3CAM4fbGg56H118rgUfEzDkB Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 2020/7/15 =E4=B8=8B=E5=8D=889:49, Chris Down wrote: > Hi Wenruo, >=20 > While testing my pending patches on top of linux-next, I encountered a > bug that seems related to this patch during btrfs unmount. Specifically= , > a null pointer dereference in kobject_del inside btrfs_sysfs_del_qgroup= s > from close_ctree. >=20 > The fix may be as simple as checking if the kobject is initialised, > although perhaps it should always be initialised in this case, so I'll > leave you to work out what the real issue is :-) Thank you very much for the report. May I ask if the qgroup is enabled? Or qgroup is not enabled at all? Thanks, Qu >=20 >=20 > =C2=A0=C2=A0=C2=A0 RIP: kobject_del+0x1/0x20 >=20 > =C2=A0=C2=A0=C2=A0 [...] >=20 > =C2=A0=C2=A0=C2=A0 Call Trace: > =C2=A0=C2=A0=C2=A0=C2=A0 btrfs_sysfs_del_qgroups+0xa5/0xe0 > =C2=A0=C2=A0=C2=A0=C2=A0 close_ctree+0x1cd/0x2c0 > =C2=A0=C2=A0=C2=A0=C2=A0 generic_shutdown_super+0x6c/0x100 > =C2=A0=C2=A0=C2=A0=C2=A0 kill_anon_super+0x14/0x30 > =C2=A0=C2=A0=C2=A0=C2=A0 btrfs_kill_super+0x12/0x20 > =C2=A0=C2=A0=C2=A0=C2=A0 deactivate_locked_super+0x36/0x90 > =C2=A0=C2=A0=C2=A0=C2=A0 cleanup_mnt+0x12d/0x190 > =C2=A0=C2=A0=C2=A0=C2=A0 task_work_run+0x5c/0x90 > =C2=A0=C2=A0=C2=A0=C2=A0 __prepare_exit_to_usermode+0x164/0x170 > =C2=A0=C2=A0=C2=A0=C2=A0 [...] >=20 > Thanks, >=20 > Chris --jV1jsiF3t3CAM4fbGg56H118rgUfEzDkB-- --vkE7UOlaGx0P74iBgXS0rx8SU5D6UI2qR Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEELd9y5aWlW6idqkLhwj2R86El/qgFAl8PnAwACgkQwj2R86El /qgFfgf/WYL25kfquKQixj8kyTMdbLBnWs1iQ+sVNJCeoctHm2DDUEFED5hxWdDO TWtp/GLCSf5RVsXMZjr1Fc5BYBMByI6PW8+tskh4TjBbGhAEIGTNo8qyvmtEsglR 9Vsn8FOjcIODKEgmTYftBh0+lhJH4cVoT7h5KFs52SUcix7nLLZJKfXuckbDPXsH AEsWZ2osdpxXNUzocaJPZu2zHdsIeTCmlnhndjNoK+SZrOWyPsy0cq1xePt38EN4 Y7GzW7146PB8ZVlh/L3PX3nFacLkJq3GdpigP0+g+vcti97P/juGZFzodSEZ1kLv nyN8fvQMGLzPC93zXnxTAUlL7p0QkA== =KbQq -----END PGP SIGNATURE----- --vkE7UOlaGx0P74iBgXS0rx8SU5D6UI2qR--