struct rb_entry *__lookup_rb_tree_ret(struct rb_root *root,
				struct rb_entry *cached_re,
				unsigned int ofs,
				struct rb_entry **prev_entry,
				struct rb_entry **next_entry,
				struct rb_node ***insert_p,
				struct rb_node **insert_parent,
				bool force)
{
	struct rb_node **pnode = &root->rb_node;
	struct rb_node *parent = NULL, *tmp_node;
	struct rb_entry *re = cached_re;

	*insert_p = NULL;
	*insert_parent = NULL;
	*prev_entry = NULL;
	*next_entry = NULL;

	if (RB_EMPTY_ROOT(root))
		return NULL;

	if (re) {
		if (re->ofs <= ofs && re->ofs + re->len > ofs)
			goto lookup_neighbors;
	}

	while (*pnode) {
		parent = *pnode;
		re = rb_entry(*pnode, struct rb_entry, rb_node);

		if (ofs < re->ofs)
			pnode = &(*pnode)->rb_left;
		else if (ofs >= re->ofs + re->len)
			pnode = &(*pnode)->rb_right;
		else
			goto lookup_neighbors;
	}

	*insert_p = pnode;
	*insert_parent = parent;

	re = rb_entry(parent, struct rb_entry, rb_node);
	tmp_node = parent;
	if (parent && ofs > re->ofs)
		tmp_node = rb_next(parent);
	*next_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node);

	tmp_node = parent;
	if (parent && ofs < re->ofs)
		tmp_node = rb_prev(parent);
	*prev_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node);
	return NULL;

lookup_neighbors:
	if (ofs == re->ofs || force) {
		/* lookup prev node for merging backward later */
		tmp_node = rb_prev(&re->rb_node);
		*prev_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node);
	}
	if (ofs == re->ofs + re->len - 1 || force) {
		/* lookup next node for merging frontward later */
		tmp_node = rb_next(&re->rb_node);
		*next_entry = rb_entry_safe(tmp_node, struct rb_entry, rb_node);
	}
	return re;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.