int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,
			 u8 tos, struct net_device *dev)
{
	struct fib_result res;
	int err;

	tos &= IPTOS_RT_MASK;
	rcu_read_lock();
	err = ip_route_input_rcu(skb, daddr, saddr, tos, dev, &res);
	rcu_read_unlock();

	return err;
}

The product dereferences a pointer that it expects to be valid but is NULL.