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=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 98E3AC433E1 for ; Sun, 21 Mar 2021 04:29:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 675D56193B for ; Sun, 21 Mar 2021 04:29:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229826AbhCUE2c (ORCPT ); Sun, 21 Mar 2021 00:28:32 -0400 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:41344 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S229556AbhCUE2H (ORCPT ); Sun, 21 Mar 2021 00:28:07 -0400 Received: from cwcc.thunk.org (pool-72-74-133-215.bstnma.fios.verizon.net [72.74.133.215]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 12L4S2iM007192 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 21 Mar 2021 00:28:02 -0400 Received: by cwcc.thunk.org (Postfix, from userid 15806) id E78B015C39CA; Sun, 21 Mar 2021 00:28:01 -0400 (EDT) Date: Sun, 21 Mar 2021 00:28:01 -0400 From: "Theodore Ts'o" To: Jan Kara Cc: linux-ext4@vger.kernel.org, syzbot+628472a2aac693ab0fcd@syzkaller.appspotmail.com, stable@vger.kernel.org Subject: Re: [PATCH] ext4: Fix timer use-after-free on failed mount Message-ID: References: <20210315165906.2175-1-jack@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210315165906.2175-1-jack@suse.cz> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Mon, Mar 15, 2021 at 05:59:06PM +0100, Jan Kara wrote: > When filesystem mount fails because of corrupted filesystem we first > cancel the s_err_report timer reminding fs errors every day and only > then we flush s_error_work. However s_error_work may report another fs > error and re-arm timer thus resulting in timer use-after-free. Fix the > problem by first flushing the work and only after that canceling the > s_err_report timer. > > Reported-by: syzbot+628472a2aac693ab0fcd@syzkaller.appspotmail.com > Fixes: 2d01ddc86606 ("ext4: save error info to sb through journal if available") > CC: stable@vger.kernel.org > Signed-off-by: Jan Kara Thanks, applied. - Ted