[lkml]   [2012]   [Mar]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[ 084/108] ext4: check for zero length extent
3.0-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.

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
@@ -341,6 +341,8 @@ 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);

 \ /
  Last update: 2012-03-31 00:45    [W:0.470 / U:1.332 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site