diff options
authorQu Wenruo <>2018-03-30 13:48:54 +0800
committerDavid Sterba <>2018-04-24 13:00:11 +0200
commit43dea2af140fe21111e7ce8491cad2724d73b2d4 (patch)
parent98d5d325a887b6c061096c141eef10755762bbcf (diff)
btrfs-progs: extent_io: Init eb->lru to avoid NULL pointer dereference
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 <> Reviewed-by: Lu Fengqi <> Signed-off-by: David Sterba <>
1 files changed, 1 insertions, 0 deletions
diff --git a/extent_io.c b/extent_io.c
index 986ad5c0..31177823 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->lru);
return eb;