static int ip_mkroute_input(struct sk_buff *skb,
			    struct fib_result *res,
			    struct in_device *in_dev,
			    __be32 daddr, __be32 saddr, u32 tos)
{
#ifdef CONFIG_IP_ROUTE_MULTIPATH
	if (res->fi && res->fi->fib_nhs > 1) {
		int h = fib_multipath_hash(res->fi, NULL, skb);

		fib_select_multipath(res, h);
	}
#endif

	/* create a routing cache entry */
	return __mkroute_input(skb, res, in_dev, daddr, saddr, tos);
}

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