void ip4_datagram_release_cb(struct sock *sk)
{
	const struct inet_sock *inet = inet_sk(sk);
	const struct ip_options_rcu *inet_opt;
	__be32 daddr = inet->inet_daddr;
	struct flowi4 fl4;
	struct rtable *rt;

	if (! __sk_dst_get(sk) || __sk_dst_check(sk, 0))
		return;

	rcu_read_lock();
	inet_opt = rcu_dereference(inet->inet_opt);
	if (inet_opt && inet_opt->opt.srr)
		daddr = inet_opt->opt.faddr;
	rt = ip_route_output_ports(sock_net(sk), &fl4, sk, daddr,
				   inet->inet_saddr, inet->inet_dport,
				   inet->inet_sport, sk->sk_protocol,
				   RT_CONN_FLAGS(sk), sk->sk_bound_dev_if);
	if (!IS_ERR(rt))
		__sk_dst_set(sk, &rt->dst);
	rcu_read_unlock();
}
Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.