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| author | Theodore Ts'o <tytso@mit.edu> | 2010-05-17 03:00:00 (GMT) |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2010-05-17 03:00:00 (GMT) |
| commit | f70f362b4a6fe47c239dbfb3efc0cc2c10e4f09c (patch) | |
| tree | b9db08f3675d1cc0ed7d1af08418f5f5ba554ca6 | |
| parent | 12e9b892002d9af057655d35b44db8ee9243b0dc (diff) | |
| download | linux-f70f362b4a6fe47c239dbfb3efc0cc2c10e4f09c.tar.xz | |
ext4: Avoid crashing on NULL ptr dereference on a filesystem error
If the EOFBLOCK_FL flag is set when it should not be and the inode is
zero length, then eh_entries is zero, and ex is NULL, so dereferencing
ex to print ex->ee_block causes a kernel OOPS in
ext4_ext_map_blocks().
On top of that, the error message which is printed isn't very helpful.
So we fix this by printing something more explanatory which doesn't
involve trying to print ex->ee_block.
Addresses-Google-Bug: #2655740
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
| -rw-r--r-- | fs/ext4/extents.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 42d8ce9..e40d2b7 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -3370,8 +3370,9 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, */ if (unlikely(path[depth].p_ext == NULL && depth != 0)) { EXT4_ERROR_INODE(inode, "bad extent address " - "iblock: %d, depth: %d pblock %lld", - map->m_lblk, depth, path[depth].p_block); + "lblock: %lu, depth: %d pblock %lld", + (unsigned long) map->m_lblk, depth, + path[depth].p_block); err = -EIO; goto out2; } @@ -3501,8 +3502,8 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, if (unlikely(ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))) { if (unlikely(!eh->eh_entries)) { EXT4_ERROR_INODE(inode, - "eh->eh_entries == 0 ee_block %d", - ex->ee_block); + "eh->eh_entries == 0 and " + "EOFBLOCKS_FL set"); err = -EIO; goto out2; } |