static inline int get_xps_queue(struct net_device *dev, struct sk_buff *skb)
{
#ifdef CONFIG_XPS
	struct xps_dev_maps *dev_maps;
	struct xps_map *map;
	int queue_index = -1;

	rcu_read_lock();
	dev_maps = rcu_dereference(dev->xps_maps);
	if (dev_maps) {
		unsigned int tci = skb->sender_cpu - 1;

		if (dev->num_tc) {
			tci *= dev->num_tc;
			tci += netdev_get_prio_tc_map(dev, skb->priority);
		}

		map = rcu_dereference(dev_maps->cpu_map[tci]);
		if (map) {
			if (map->len == 1)
				queue_index = map->queues[0];
			else
				queue_index = map->queues[reciprocal_scale(skb_get_hash(skb),
									   map->len)];
			if (unlikely(queue_index >= dev->real_num_tx_queues))
				queue_index = -1;
		}
	}
	rcu_read_unlock();

	return queue_index;
#else
	return -1;
#endif
}

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