static void nfc_llcp_recv_ui(struct nfc_llcp_local *local,
			     struct sk_buff *skb)
{
	struct nfc_llcp_sock *llcp_sock;
	struct nfc_llcp_ui_cb *ui_cb;
	u8 dsap, ssap;

	dsap = nfc_llcp_dsap(skb);
	ssap = nfc_llcp_ssap(skb);

	ui_cb = nfc_llcp_ui_skb_cb(skb);
	ui_cb->dsap = dsap;
	ui_cb->ssap = ssap;

	pr_debug("%d %d\n", dsap, ssap);

	/* We're looking for a bound socket, not a client one */
	llcp_sock = nfc_llcp_sock_get(local, dsap, LLCP_SAP_SDP);
	if (llcp_sock == NULL || llcp_sock->sk.sk_type != SOCK_DGRAM)
		return;

	/* There is no sequence with UI frames */
	skb_pull(skb, LLCP_HEADER_SIZE);
	if (!sock_queue_rcv_skb(&llcp_sock->sk, skb)) {
		/*
		 * UI frames will be freed from the socket layer, so we
		 * need to keep them alive until someone receives them.
		 */
		skb_get(skb);
	} else {
		pr_err("Receive queue is full\n");
	}

	nfc_llcp_sock_put(llcp_sock);
}

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