static struct sk_buff *fm10k_fetch_rx_buffer(struct fm10k_ring *rx_ring,
					     union fm10k_rx_desc *rx_desc,
					     struct sk_buff *skb)
{
	unsigned int size = le16_to_cpu(rx_desc->w.length);
	struct fm10k_rx_buffer *rx_buffer;
	struct page *page;

	rx_buffer = &rx_ring->rx_buffer[rx_ring->next_to_clean];
	page = rx_buffer->page;
	prefetchw(page);

	if (likely(!skb)) {
		void *page_addr = page_address(page) +
				  rx_buffer->page_offset;

		/* prefetch first cache line of first page */
		prefetch(page_addr);
#if L1_CACHE_BYTES < 128
		prefetch(page_addr + L1_CACHE_BYTES);
#endif

		/* allocate a skb to store the frags */
		skb = napi_alloc_skb(&rx_ring->q_vector->napi,
				     FM10K_RX_HDR_LEN);
		if (unlikely(!skb)) {
			rx_ring->rx_stats.alloc_failed++;
			return NULL;
		}

		/* we will be copying header into skb->data in
		 * pskb_may_pull so it is in our interest to prefetch
		 * it now to avoid a possible cache miss
		 */
		prefetchw(skb->data);
	}

	/* we are reusing so sync this buffer for CPU use */
	dma_sync_single_range_for_cpu(rx_ring->dev,
				      rx_buffer->dma,
				      rx_buffer->page_offset,
				      size,
				      DMA_FROM_DEVICE);

	/* pull page into skb */
	if (fm10k_add_rx_frag(rx_buffer, size, rx_desc, skb)) {
		/* hand second half of page back to the ring */
		fm10k_reuse_rx_page(rx_ring, rx_buffer);
	} else {
		/* we are not reusing the buffer so unmap it */
		dma_unmap_page(rx_ring->dev, rx_buffer->dma,
			       PAGE_SIZE, DMA_FROM_DEVICE);
	}

	/* clear contents of rx_buffer */
	rx_buffer->page = NULL;

	return skb;
}

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