static void tg3_tx_skb_unmap(struct tg3_napi *tnapi, u32 entry, int last)
{
	int i;
	struct sk_buff *skb;
	struct tg3_tx_ring_info *txb = &tnapi->tx_buffers[entry];

	skb = txb->skb;
	txb->skb = NULL;

	pci_unmap_single(tnapi->tp->pdev,
			 dma_unmap_addr(txb, mapping),
			 skb_headlen(skb),
			 PCI_DMA_TODEVICE);

	while (txb->fragmented) {
		txb->fragmented = false;
		entry = NEXT_TX(entry);
		txb = &tnapi->tx_buffers[entry];
	}

	for (i = 0; i <= last; i++) {
		const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];

		entry = NEXT_TX(entry);
		txb = &tnapi->tx_buffers[entry];

		pci_unmap_page(tnapi->tp->pdev,
			       dma_unmap_addr(txb, mapping),
			       skb_frag_size(frag), PCI_DMA_TODEVICE);

		while (txb->fragmented) {
			txb->fragmented = false;
			entry = NEXT_TX(entry);
			txb = &tnapi->tx_buffers[entry];
		}
	}
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.