| Message ID | 20180330054857.6106-3-wqu@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/extent_io.c b/extent_io.c index 986ad5c0577c..3117782335ab 100644 --- a/extent_io.c +++ b/extent_io.c @@ -564,6 +564,7 @@ static struct extent_buffer *__alloc_extent_buffer(struct extent_io_tree *tree, eb->cache_node.start = bytenr; eb->cache_node.size = blocksize; INIT_LIST_HEAD(&eb->recow); + INIT_LIST_HEAD(&eb->lru); return eb; }
eb->lru is not initialized in __alloc_extent_buffer(), so in the following call chain, it could call NULL pointer dereference: btrfs_clone_extent_buffer() |- __alloc_extent_buffer() |- Now eb->lru is NULL (not initialized) free_extent_buffer_final() |- list_del_init(&eb->lru) Thankfully, current btrfs-progs won't trigger such bug as the only btrfs_clone_extent_buffer() user is paths_from_inode(), which is not used by anyone. (But due to the usefulness of that function in future offline scrub, I'd like to keep this dead code) Anyway, initialize eb->lru in __alloc_extent_bufer() bring no harm. Signed-off-by: Qu Wenruo <wqu@suse.com> --- extent_io.c | 1 + 1 file changed, 1 insertion(+)