From 31d4f3a2f3c73f279ff96a7135d7202ef6833f12 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sun, 11 Mar 2012 23:30:16 -0400 Subject: [PATCH] ext4: check for zero length extent 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" Cc: stable@kernel.org --- fs/ext4/extents.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 74f23c292e1b..4394a757aa4c 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -300,6 +300,8 @@ static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext) 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); }