Commit 03cc1e67 authored by Kent Overstreet's avatar Kent Overstreet
Browse files

bcachefs: Fix null ptr deref in bch2_backpointer_get_node() 



bch2_btree_iter_peek_node() can return a NULL ptr (when the tree is
shorter than the search depth); handle this with an early return.

Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
Reported-by: default avatarDan Carpenter <dan.carpenter@linaro.org>
Fixes: https://lore.kernel.org/linux-bcachefs/5fc3c28b-c232-4ec7-b0ac-4ef220ddf976@moroto.mountain/T/


Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
parent 274c2f8f

fs/bcachefs/backpointers.c

+5 −5
Original line number Diff line number Diff line
@@ -313,17 +313,17 @@ struct btree *bch2_backpointer_get_node(struct btree_trans *trans, 
				  bp.level - 1,

				  0);

	b = bch2_btree_iter_peek_node(iter);

	if (IS_ERR(b))

	if (IS_ERR_OR_NULL(b))

		goto err;



	BUG_ON(b->c.level != bp.level - 1);



	if (b && extent_matches_bp(c, bp.btree_id, bp.level,

	if (extent_matches_bp(c, bp.btree_id, bp.level,

			      bkey_i_to_s_c(&b->key),

			      bucket, bp))

		return b;



	if (b && btree_node_will_make_reachable(b)) {

	if (btree_node_will_make_reachable(b)) {

		b = ERR_PTR(-BCH_ERR_backpointer_to_overwritten_btree_node);

	} else {

		backpointer_not_found(trans, bp_pos, bp, bkey_i_to_s_c(&b->key));