static int l2tp_ip_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
	struct inet_sock *inet = inet_sk(sk);
	struct sockaddr_l2tpip *addr = (struct sockaddr_l2tpip *) uaddr;
	struct net *net = sock_net(sk);
 	int ret;
 	int chk_addr_ret;
 
	if (!sock_flag(sk, SOCK_ZAPPED))
		return -EINVAL;
 	if (addr_len < sizeof(struct sockaddr_l2tpip))
 		return -EINVAL;
 	if (addr->l2tp_family != AF_INET)
		return -EINVAL;

	ret = -EADDRINUSE;
	read_lock_bh(&l2tp_ip_lock);
	if (__l2tp_ip_bind_lookup(net, addr->l2tp_addr.s_addr,
				  sk->sk_bound_dev_if, addr->l2tp_conn_id))
		goto out_in_use;

 	read_unlock_bh(&l2tp_ip_lock);
 
 	lock_sock(sk);
 	if (sk->sk_state != TCP_CLOSE || addr_len < sizeof(struct sockaddr_l2tpip))
 		goto out;
 
	chk_addr_ret = inet_addr_type(net, addr->l2tp_addr.s_addr);
	ret = -EADDRNOTAVAIL;
	if (addr->l2tp_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
	    chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
		goto out;

	if (addr->l2tp_addr.s_addr)
		inet->inet_rcv_saddr = inet->inet_saddr = addr->l2tp_addr.s_addr;
	if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
		inet->inet_saddr = 0;  /* Use device */
	sk_dst_reset(sk);

	l2tp_ip_sk(sk)->conn_id = addr->l2tp_conn_id;

	write_lock_bh(&l2tp_ip_lock);
	sk_add_bind_node(sk, &l2tp_ip_bind_table);
	sk_del_node_init(sk);
	write_unlock_bh(&l2tp_ip_lock);
	ret = 0;
	sock_reset_flag(sk, SOCK_ZAPPED);

out:
	release_sock(sk);

	return ret;

out_in_use:
	read_unlock_bh(&l2tp_ip_lock);

	return ret;
}

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.