From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20120330194854.501801795@linuxfoundation.org> Date: Fri, 30 Mar 2012 12:50:45 -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, "Theodore Tso" Subject: [ 140/175] ext4: check for zero length extent In-Reply-To: <20120330195801.GA31806@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Theodore Ts'o commit 31d4f3a2f3c73f279ff96a7135d7202ef6833f12 upstream. Explicitly test for an extent whose length is zero, and flag that as a corrupted extent. This avoids a kernel BUG_ON assertion failure. Tested: Without this patch, the file system image found in tests/f_ext_zero_len/image.gz in the latest e2fsprogs sources causes a kernel panic. With this patch, an ext4 file system error is noted instead, and the file system is marked as being corrupted. https://bugzilla.kernel.org/show_bug.cgi?id=42859 Signed-off-by: "Theodore Ts'o" Signed-off-by: Greg Kroah-Hartman --- fs/ext4/extents.c | 2 ++ 1 file changed, 2 insertions(+) --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -300,6 +300,8 @@ static int ext4_valid_extent(struct inod ext4_fsblk_t block = ext4_ext_pblock(ext); int len = ext4_ext_get_actual_len(ext); + if (len == 0) + return 0; return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len); }