btrfs_next_old_leaf() doesn't check if the target root is NULL or not, resulting the null-ptr-deref. Add sanity check for btrfs root before using it in btrfs_next_old_leaf().
Found by code review.
Cc: stable@vger.kernel.org Fixes: d96b34248c2f ("btrfs: make send work with concurrent block group relocation") Signed-off-by: Ma Ke make24@iscas.ac.cn --- fs/btrfs/ctree.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 4e2e1c38d33a..1a3fc3863860 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -4794,13 +4794,17 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path, int level; struct extent_buffer *c; struct extent_buffer *next; - struct btrfs_fs_info *fs_info = root->fs_info; + struct btrfs_fs_info *fs_info; struct btrfs_key key; bool need_commit_sem = false; u32 nritems; int ret; int i;
+ if (!root) + return -EINVAL; + + fs_info = root->fs_info; /* * The nowait semantics are used only for write paths, where we don't * use the tree mod log and sequence numbers.