| From be35fdaf86305ae807dc170139a50ab9a0dd4e09 Mon Sep 17 00:00:00 2001 |
| From: Theodore Ts'o <tytso@mit.edu> |
| Date: Sun, 16 May 2010 23:00:00 -0400 |
| Subject: [PATCH] ext4: Avoid crashing on NULL ptr dereference on a filesystem error |
| |
| commit f70f362b4a6fe47c239dbfb3efc0cc2c10e4f09c upstream. |
| |
| 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> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| --- |
| 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 a1d3f7c..8e8a7a4 100644 |
| --- a/fs/ext4/extents.c |
| +++ b/fs/ext4/extents.c |
| @@ -3381,8 +3381,9 @@ int ext4_ext_get_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", |
| - iblock, depth, path[depth].p_block); |
| + "iblock: %lu, depth: %d pblock %lld", |
| + (unsigned long) iblock, depth, |
| + path[depth].p_block); |
| err = -EIO; |
| goto out2; |
| } |
| @@ -3512,8 +3513,8 @@ int ext4_ext_get_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; |
| } |
| -- |
| 1.7.0.4 |
| |
