static void hns_nic_reuse_page(struct sk_buff *skb, int i,
			       struct hnae_ring *ring, int pull_len,
			       struct hnae_desc_cb *desc_cb)
{
	struct hnae_desc *desc;
	int truesize, size;
	int last_offset;
	bool twobufs;

	twobufs = ((PAGE_SIZE < 8192) &&
		hnae_buf_size(ring) == HNS_BUFFER_SIZE_2048);

	desc = &ring->desc[ring->next_to_clean];
	size = le16_to_cpu(desc->rx.size);

	if (twobufs) {
		truesize = hnae_buf_size(ring);
	} else {
		truesize = ALIGN(size, L1_CACHE_BYTES);
		last_offset = hnae_page_size(ring) - hnae_buf_size(ring);
	}

	skb_add_rx_frag(skb, i, desc_cb->priv, desc_cb->page_offset + pull_len,
			size - pull_len, truesize - pull_len);

	 /* avoid re-using remote pages,flag default unreuse */
	if (unlikely(page_to_nid(desc_cb->priv) != numa_node_id()))
		return;

	if (twobufs) {
		/* if we are only owner of page we can reuse it */
		if (likely(page_count(desc_cb->priv) == 1)) {
			/* flip page offset to other buffer */
			desc_cb->page_offset ^= truesize;

			desc_cb->reuse_flag = 1;
			/* bump ref count on page before it is given*/
			get_page(desc_cb->priv);
		}
		return;
	}

	/* move offset up to the next cache line */
	desc_cb->page_offset += truesize;

	if (desc_cb->page_offset <= last_offset) {
		desc_cb->reuse_flag = 1;
		/* bump ref count on page before it is given*/
		get_page(desc_cb->priv);
	}
}

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.