From: akpm@linux-foundation.org Subject: + ext3-ext4-avoid-divide-by-zero.patch added to -mm tree Date: Wed, 12 Dec 2007 02:27:28 -0800 Message-ID: <200712121027.lBCARSKQ005179@imap1.linux-foundation.org> Cc: Andries.Brouwer@cwi.nl, alan@redhat.com, linux-ext4@vger.kernel.org To: mm-commits@vger.kernel.org Return-path: Received: from smtp2.linux-foundation.org ([207.189.120.14]:34965 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758910AbXLLK2W (ORCPT ); Wed, 12 Dec 2007 05:28:22 -0500 Sender: linux-ext4-owner@vger.kernel.org List-ID: The patch titled ext3, ext4: avoid divide by zero has been added to the -mm tree. Its filename is ext3-ext4-avoid-divide-by-zero.patch *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this ------------------------------------------------------ Subject: ext3, ext4: avoid divide by zero From: "Andries E. Brouwer" As it turns out, the kernel divides by EXT3_INODES_PER_GROUP(s) when mounting an ext3 filesystem. If that number is zero, a crash follows. Below a patch. This crash was reported by Joeri de Ruiter, Carst Tankink and Pim Vullers. Cc: Acked-by: Alan Cox Signed-off-by: Andrew Morton --- fs/ext3/super.c | 2 +- fs/ext4/super.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff -puN fs/ext3/super.c~ext3-ext4-avoid-divide-by-zero fs/ext3/super.c --- a/fs/ext3/super.c~ext3-ext4-avoid-divide-by-zero +++ a/fs/ext3/super.c @@ -1676,7 +1676,7 @@ static int ext3_fill_super (struct super sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group); sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group); sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group); - if (EXT3_INODE_SIZE(sb) == 0) + if (EXT3_INODE_SIZE(sb) == 0 || EXT3_INODES_PER_GROUP(sb) == 0) goto cantfind_ext3; sbi->s_inodes_per_block = blocksize / EXT3_INODE_SIZE(sb); if (sbi->s_inodes_per_block == 0) diff -puN fs/ext4/super.c~ext3-ext4-avoid-divide-by-zero fs/ext4/super.c --- a/fs/ext4/super.c~ext3-ext4-avoid-divide-by-zero +++ a/fs/ext4/super.c @@ -1797,7 +1797,7 @@ static int ext4_fill_super (struct super sbi->s_desc_size = EXT4_MIN_DESC_SIZE; sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group); sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group); - if (EXT4_INODE_SIZE(sb) == 0) + if (EXT4_INODE_SIZE(sb) == 0 || EXT4_INODES_PER_GROUP(sb) == 0) goto cantfind_ext4; sbi->s_inodes_per_block = blocksize / EXT4_INODE_SIZE(sb); if (sbi->s_inodes_per_block == 0) _ Patches currently in -mm which might be from Andries.Brouwer@cwi.nl are ext3-ext4-avoid-divide-by-zero.patch mnt_unbindable-fix.patch