From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752908AbaBLITx (ORCPT ); Wed, 12 Feb 2014 03:19:53 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:50298 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752194AbaBLIOK (ORCPT ); Wed, 12 Feb 2014 03:14:10 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Al Viro" , "Theodore Ts'o" , "Al Viro" Date: Wed, 12 Feb 2014 08:10:12 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 36/79] ext4: fix del_timer() misuse for ->s_err_report In-Reply-To: X-SA-Exim-Connect-IP: 91.84.160.45 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.55-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Al Viro commit 9105bb149bbbc555d2e11ba5166dfe7a24eae09e upstream. That thing should be del_timer_sync(); consider what happens if ext4_put_super() call of del_timer() happens to come just as it's getting run on another CPU. Since that timer reschedules itself to run next day, you are pretty much guaranteed that you'll end up with kfree'd scheduled timer, with usual fun consequences. AFAICS, that's -stable fodder all way back to 2010... [the second del_timer_sync() is almost certainly not needed, but it doesn't hurt either] Signed-off-by: Al Viro Signed-off-by: "Theodore Ts'o" [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- fs/ext4/super.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -819,7 +819,7 @@ static void ext4_put_super(struct super_ ext4_abort(sb, "Couldn't clean up the journal"); } - del_timer(&sbi->s_err_report); + del_timer_sync(&sbi->s_err_report); ext4_release_system_zone(sb); ext4_mb_release(sb); ext4_ext_release(sb); @@ -3961,7 +3961,7 @@ failed_mount_wq: sbi->s_journal = NULL; } failed_mount3: - del_timer(&sbi->s_err_report); + del_timer_sync(&sbi->s_err_report); if (sbi->s_flex_groups) ext4_kvfree(sbi->s_flex_groups); percpu_counter_destroy(&sbi->s_freeclusters_counter);