static int tg3_alloc_rx_data(struct tg3 *tp, struct tg3_rx_prodring_set *tpr,
			     u32 opaque_key, u32 dest_idx_unmasked,
			     unsigned int *frag_size)
{
	struct tg3_rx_buffer_desc *desc;
	struct ring_info *map;
	u8 *data;
	dma_addr_t mapping;
	int skb_size, data_size, dest_idx;

	switch (opaque_key) {
	case RXD_OPAQUE_RING_STD:
		dest_idx = dest_idx_unmasked & tp->rx_std_ring_mask;
		desc = &tpr->rx_std[dest_idx];
		map = &tpr->rx_std_buffers[dest_idx];
		data_size = tp->rx_pkt_map_sz;
		break;

	case RXD_OPAQUE_RING_JUMBO:
		dest_idx = dest_idx_unmasked & tp->rx_jmb_ring_mask;
		desc = &tpr->rx_jmb[dest_idx].std;
		map = &tpr->rx_jmb_buffers[dest_idx];
		data_size = TG3_RX_JMB_MAP_SZ;
		break;

	default:
		return -EINVAL;
	}

	/* Do not overwrite any of the map or rp information
	 * until we are sure we can commit to a new buffer.
	 *
	 * Callers depend upon this behavior and assume that
	 * we leave everything unchanged if we fail.
	 */
	skb_size = SKB_DATA_ALIGN(data_size + TG3_RX_OFFSET(tp)) +
		   SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
	if (skb_size <= PAGE_SIZE) {
		data = netdev_alloc_frag(skb_size);
		*frag_size = skb_size;
	} else {
		data = kmalloc(skb_size, GFP_ATOMIC);
		*frag_size = 0;
	}
	if (!data)
		return -ENOMEM;

	mapping = pci_map_single(tp->pdev,
				 data + TG3_RX_OFFSET(tp),
				 data_size,
				 PCI_DMA_FROMDEVICE);
	if (unlikely(pci_dma_mapping_error(tp->pdev, mapping))) {
		tg3_frag_free(skb_size <= PAGE_SIZE, data);
		return -EIO;
	}

	map->data = data;
	dma_unmap_addr_set(map, mapping, mapping);

	desc->addr_hi = ((u64)mapping >> 32);
	desc->addr_lo = ((u64)mapping & 0xffffffff);

	return data_size;
}

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.