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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 555C1C433E0 for ; Wed, 10 Jun 2020 20:21:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 349F420760 for ; Wed, 10 Jun 2020 20:21:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727002AbgFJUVe (ORCPT ); Wed, 10 Jun 2020 16:21:34 -0400 Received: from out03.mta.xmission.com ([166.70.13.233]:33832 "EHLO out03.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726828AbgFJUVe (ORCPT ); Wed, 10 Jun 2020 16:21:34 -0400 Received: from in02.mta.xmission.com ([166.70.13.52]) by out03.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jj7E3-0000Ye-35; Wed, 10 Jun 2020 14:21:31 -0600 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95] helo=x220.xmission.com) by in02.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.87) (envelope-from ) id 1jj7E2-00080u-Ef; Wed, 10 Jun 2020 14:21:30 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Alexey Gladkov Cc: syzbot , adobriyan@gmail.com, keescook@chromium.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk References: <20200610130422.1197386-1-gladkov.alexey@gmail.com> <20200610183549.1234214-1-gladkov.alexey@gmail.com> Date: Wed, 10 Jun 2020 15:17:22 -0500 In-Reply-To: <20200610183549.1234214-1-gladkov.alexey@gmail.com> (Alexey Gladkov's message of "Wed, 10 Jun 2020 20:35:49 +0200") Message-ID: <87eeqmzne5.fsf@x220.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1jj7E2-00080u-Ef;;;mid=<87eeqmzne5.fsf@x220.int.ebiederm.org>;;;hst=in02.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX18c/i2m4LzZvVR3NXfr4aSXpqcWLF2oyW0= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: [PATCH v2] proc: s_fs_info may be NULL when proc_kill_sb is called X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Alexey Gladkov writes: > syzbot found that proc_fill_super() fails before filling up sb->s_fs_info, > deactivate_locked_super() will be called and sb->s_fs_info will be NULL. > The proc_kill_sb() does not expect fs_info to be NULL which is wrong. > > Link: https://lore.kernel.org/lkml/0000000000002d7ca605a7b8b1c5@google.com > Reported-by: syzbot+4abac52934a48af5ff19@syzkaller.appspotmail.com > Fixes: fa10fed30f25 ("proc: allow to mount many instances of proc in one pid namespace") > Signed-off-by: Alexey Gladkov applied Eric