static void br_multicast_add_router(struct net_bridge *br,
				    struct net_bridge_port *port)
{
	struct net_bridge_port *p;
	struct hlist_node *slot = NULL;

	hlist_for_each_entry(p, &br->router_list, rlist) {
		if ((unsigned long) port >= (unsigned long) p)
			break;
		slot = &p->rlist;
	}

	if (slot)
		hlist_add_after_rcu(slot, &port->rlist);
	else
		hlist_add_head_rcu(&port->rlist, &br->router_list);
}

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.