From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755338Ab2HTENp (ORCPT ); Mon, 20 Aug 2012 00:13:45 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:59366 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754927Ab2HTD6i (ORCPT ); Sun, 19 Aug 2012 23:58:38 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg KH , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, =?UTF-8?q?Maciej=20=C5=BBenczykowski?= , Marti Raudsepp , Fengguang Wu , "Theodore Tso" Subject: =?UTF-8?q?=5B=2019/32=5D=20ext4=3A=20fix=20kernel=20BUG=20on=20large-scale=20rm=20-rf=20commands?= Date: Sun, 19 Aug 2012 20:57:15 -0700 Message-Id: <20120820035650.527607576@linuxfoundation.org> X-Mailer: git-send-email 1.7.10.2.565.gbd578b5 In-Reply-To: <20120820035647.862247088@linuxfoundation.org> References: <20120820035647.862247088@linuxfoundation.org> User-Agent: quilt/0.60-20.5 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg KH 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Theodore Ts'o commit 89a4e48f8479f8145eca9698f39fe188c982212f upstream. Commit 968dee7722: "ext4: fix hole punch failure when depth is greater than 0" introduced a regression in v3.5.1/v3.6-rc1 which caused kernel crashes when users ran run "rm -rf" on large directory hierarchy on ext4 filesystems on RAID devices: BUG: unable to handle kernel NULL pointer dereference at 0000000000000028 Process rm (pid: 18229, threadinfo ffff8801276bc000, task ffff880123631710) Call Trace: [] ? __ext4_handle_dirty_metadata+0x83/0x110 [] ext4_ext_truncate+0x193/0x1d0 [] ? ext4_mark_inode_dirty+0x7f/0x1f0 [] ext4_truncate+0xf5/0x100 [] ext4_evict_inode+0x461/0x490 [] evict+0xa2/0x1a0 [] iput+0x103/0x1f0 [] do_unlinkat+0x154/0x1c0 [] ? sys_newfstatat+0x2a/0x40 [] sys_unlinkat+0x1b/0x50 [] system_call_fastpath+0x16/0x1b Code: 8b 4d 20 0f b7 41 02 48 8d 04 40 48 8d 04 81 49 89 45 18 0f b7 49 02 48 83 c1 01 49 89 4d 00 e9 ae f8 ff ff 0f 1f 00 49 8b 45 28 <48> 8b 40 28 49 89 45 20 e9 85 f8 ff ff 0f 1f 80 00 00 00 RIP [] ext4_ext_remove_space+0xa34/0xdf0 This could be reproduced as follows: The problem in commit 968dee7722 was that caused the variable 'i' to be left uninitialized if the truncate required more space than was available in the journal. This resulted in the function ext4_ext_truncate_extend_restart() returning -EAGAIN, which caused ext4_ext_remove_space() to restart the truncate operation after starting a new jbd2 handle. Reported-by: Maciej Żenczykowski Reported-by: Marti Raudsepp Tested-by: Fengguang Wu Signed-off-by: "Theodore Ts'o" Signed-off-by: Greg Kroah-Hartman --- fs/ext4/extents.c | 1 + 1 file changed, 1 insertion(+) --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -2596,6 +2596,7 @@ cont: } path[0].p_depth = depth; path[0].p_hdr = ext_inode_hdr(inode); + i = 0; if (ext4_ext_check(inode, path[0].p_hdr, depth)) { err = -EIO;