commit f70f362b4a6fe47c239dbfb3efc0cc2c10e4f09c upstream (as of v2.6.34-git13)
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@xxxxxxx>
---
fs/ext4/extents.c | 11 +++++++----
1 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 5b1c104..e2d9bfb 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3275,8 +3275,8 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
*/
if (path[depth].p_ext == NULL && depth != 0) {
ext4_error(inode->i_sb, __func__, "bad extent address "
- "inode: %lu, iblock: %d, depth: %d",
- inode->i_ino, iblock, depth);
+ "inode: %lu, iblock: %lu, depth: %d",
+ inode->i_ino, (unsigned long) iblock, depth);
err = -EIO;
goto out2;
}
@@ -3412,8 +3412,11 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
} else {
WARN_ON(eh->eh_entries == 0);
ext4_error(inode->i_sb, __func__,
- "inode#%lu, eh->eh_entries = 0!", inode->i_ino);
- }
+ "inode#%lu, eh->eh_entries = 0 and "
+ "EOFBLOCKS_FL set", inode->i_ino);
+ err = -EIO;
+ goto out2;
+ }
}
err = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
if (err) {
--
1.6.6.1.1.g974db.dirty
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