int register_netdevice(struct net_device *dev)
{
	int ret;
	struct net *net = dev_net(dev);

	BUG_ON(dev_boot_phase);
	ASSERT_RTNL();

	might_sleep();

	/* When net_device's are persistent, this will be fatal. */
	BUG_ON(dev->reg_state != NETREG_UNINITIALIZED);
	BUG_ON(!net);

	spin_lock_init(&dev->addr_list_lock);
	netdev_set_addr_lockdep_class(dev);

	ret = dev_get_valid_name(net, dev, dev->name);
	if (ret < 0)
		goto out;

	/* Init, if this function is available */
	if (dev->netdev_ops->ndo_init) {
		ret = dev->netdev_ops->ndo_init(dev);
		if (ret) {
			if (ret > 0)
				ret = -EIO;
			goto out;
		}
	}

	if (((dev->hw_features | dev->features) &
	     NETIF_F_HW_VLAN_CTAG_FILTER) &&
	    (!dev->netdev_ops->ndo_vlan_rx_add_vid ||
	     !dev->netdev_ops->ndo_vlan_rx_kill_vid)) {
		netdev_WARN(dev, "Buggy VLAN acceleration in driver!\n");
		ret = -EINVAL;
		goto err_uninit;
	}

	ret = -EBUSY;
	if (!dev->ifindex)
		dev->ifindex = dev_new_index(net);
	else if (__dev_get_by_index(net, dev->ifindex))
		goto err_uninit;

	/* Transfer changeable features to wanted_features and enable
	 * software offloads (GSO and GRO).
	 */
	dev->hw_features |= NETIF_F_SOFT_FEATURES;
	dev->features |= NETIF_F_SOFT_FEATURES;

	if (dev->netdev_ops->ndo_udp_tunnel_add) {
		dev->features |= NETIF_F_RX_UDP_TUNNEL_PORT;
		dev->hw_features |= NETIF_F_RX_UDP_TUNNEL_PORT;
	}

	dev->wanted_features = dev->features & dev->hw_features;

	if (!(dev->flags & IFF_LOOPBACK))
		dev->hw_features |= NETIF_F_NOCACHE_COPY;

	/* If IPv4 TCP segmentation offload is supported we should also
	 * allow the device to enable segmenting the frame with the option
	 * of ignoring a static IP ID value.  This doesn't enable the
	 * feature itself but allows the user to enable it later.
	 */
	if (dev->hw_features & NETIF_F_TSO)
		dev->hw_features |= NETIF_F_TSO_MANGLEID;
	if (dev->vlan_features & NETIF_F_TSO)
		dev->vlan_features |= NETIF_F_TSO_MANGLEID;
	if (dev->mpls_features & NETIF_F_TSO)
		dev->mpls_features |= NETIF_F_TSO_MANGLEID;
	if (dev->hw_enc_features & NETIF_F_TSO)
		dev->hw_enc_features |= NETIF_F_TSO_MANGLEID;

	/* Make NETIF_F_HIGHDMA inheritable to VLAN devices.
	 */
	dev->vlan_features |= NETIF_F_HIGHDMA;

	/* Make NETIF_F_SG inheritable to tunnel devices.
	 */
	dev->hw_enc_features |= NETIF_F_SG | NETIF_F_GSO_PARTIAL;

	/* Make NETIF_F_SG inheritable to MPLS.
	 */
	dev->mpls_features |= NETIF_F_SG;

	ret = call_netdevice_notifiers(NETDEV_POST_INIT, dev);
	ret = notifier_to_errno(ret);
	if (ret)
		goto err_uninit;

	ret = netdev_register_kobject(dev);
	if (ret)
		goto err_uninit;
	dev->reg_state = NETREG_REGISTERED;

	__netdev_update_features(dev);

	/*
	 *	Default initial state at registry is that the
	 *	device is present.
	 */

	set_bit(__LINK_STATE_PRESENT, &dev->state);

	linkwatch_init_dev(dev);

	dev_init_scheduler(dev);
	dev_hold(dev);
	list_netdevice(dev);
	add_device_randomness(dev->dev_addr, dev->addr_len);

	/* If the device has permanent device address, driver should
	 * set dev_addr and also addr_assign_type should be set to
	 * NET_ADDR_PERM (default value).
	 */
	if (dev->addr_assign_type == NET_ADDR_PERM)
		memcpy(dev->perm_addr, dev->dev_addr, dev->addr_len);

	/* Notify protocols, that a new device appeared. */
	ret = call_netdevice_notifiers(NETDEV_REGISTER, dev);
	ret = notifier_to_errno(ret);
	if (ret) {
		rollback_registered(dev);
		dev->reg_state = NETREG_UNREGISTERED;
	}
	/*
	 *	Prevent userspace races by waiting until the network
	 *	device is fully setup before sending notifications.
	 */
	if (!dev->rtnl_link_ops ||
	    dev->rtnl_link_state == RTNL_LINK_INITIALIZED)
		rtmsg_ifinfo(RTM_NEWLINK, dev, ~0U, GFP_KERNEL);

out:
	return ret;

err_uninit:
	if (dev->netdev_ops->ndo_uninit)
		dev->netdev_ops->ndo_uninit(dev);
	if (dev->priv_destructor)
		dev->priv_destructor(dev);
	goto out;
}

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