From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758951Ab2CUVQr (ORCPT ); Wed, 21 Mar 2012 17:16:47 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:61339 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757623Ab2CUVQe (ORCPT ); Wed, 21 Mar 2012 17:16:34 -0400 Message-Id: <20120321211448.316064855@linuxfoundation.org> User-Agent: quilt/0.60-19.1 Date: Wed, 21 Mar 2012 14:14:49 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Slicky Devil , Ryusuke Konishi Subject: [ 1/8] nilfs2: fix NULL pointer dereference in nilfs_load_super_block() In-Reply-To: <20120321211522.GA28233@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ryusuke Konishi commit d7178c79d9b7c5518f9943188091a75fc6ce0675 upstream. According to the report from Slicky Devil, nilfs caused kernel oops at nilfs_load_super_block function during mount after he shrank the partition without resizing the filesystem: BUG: unable to handle kernel NULL pointer dereference at 00000048 IP: [] nilfs_load_super_block+0x17e/0x280 [nilfs2] *pde = 00000000 Oops: 0000 [#1] PREEMPT SMP ... Call Trace: [] init_nilfs+0x4b/0x2e0 [nilfs2] [] nilfs_mount+0x447/0x5b0 [nilfs2] [] mount_fs+0x36/0x180 [] vfs_kern_mount+0x51/0xa0 [] do_kern_mount+0x3e/0xe0 [] do_mount+0x169/0x700 [] sys_mount+0x6b/0xa0 [] sysenter_do_call+0x12/0x28 Code: 53 18 8b 43 20 89 4b 18 8b 4b 24 89 53 1c 89 43 24 89 4b 20 8b 43 20 c7 43 2c 00 00 00 00 23 75 e8 8b 50 68 89 53 28 8b 54 b3 20 <8b> 72 48 8b 7a 4c 8b 55 08 89 b3 84 00 00 00 89 bb 88 00 00 00 EIP: [] nilfs_load_super_block+0x17e/0x280 [nilfs2] SS:ESP 0068:ca9bbdcc CR2: 0000000000000048 This turned out due to a defect in an error path which runs if the calculated location of the secondary super block was invalid. This patch fixes it and eliminates the reported oops. Reported-by: Slicky Devil Signed-off-by: Ryusuke Konishi Tested-by: Slicky Devil Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/nilfs2/the_nilfs.c | 1 + 1 file changed, 1 insertion(+) --- a/fs/nilfs2/the_nilfs.c +++ b/fs/nilfs2/the_nilfs.c @@ -515,6 +515,7 @@ static int nilfs_load_super_block(struct brelse(sbh[1]); sbh[1] = NULL; sbp[1] = NULL; + valid[1] = 0; swp = 0; } if (!valid[swp]) {