static void tg3_recycle_rx(struct tg3_napi *tnapi,
			   struct tg3_rx_prodring_set *dpr,
			   u32 opaque_key, int src_idx,
			   u32 dest_idx_unmasked)
{
	struct tg3 *tp = tnapi->tp;
	struct tg3_rx_buffer_desc *src_desc, *dest_desc;
	struct ring_info *src_map, *dest_map;
	struct tg3_rx_prodring_set *spr = &tp->napi[0].prodring;
	int dest_idx;

	switch (opaque_key) {
	case RXD_OPAQUE_RING_STD:
		dest_idx = dest_idx_unmasked & tp->rx_std_ring_mask;
		dest_desc = &dpr->rx_std[dest_idx];
		dest_map = &dpr->rx_std_buffers[dest_idx];
		src_desc = &spr->rx_std[src_idx];
		src_map = &spr->rx_std_buffers[src_idx];
		break;

	case RXD_OPAQUE_RING_JUMBO:
		dest_idx = dest_idx_unmasked & tp->rx_jmb_ring_mask;
		dest_desc = &dpr->rx_jmb[dest_idx].std;
		dest_map = &dpr->rx_jmb_buffers[dest_idx];
		src_desc = &spr->rx_jmb[src_idx].std;
		src_map = &spr->rx_jmb_buffers[src_idx];
		break;

	default:
		return;
	}

	dest_map->data = src_map->data;
	dma_unmap_addr_set(dest_map, mapping,
			   dma_unmap_addr(src_map, mapping));
	dest_desc->addr_hi = src_desc->addr_hi;
	dest_desc->addr_lo = src_desc->addr_lo;

	/* Ensure that the update to the skb happens after the physical
	 * addresses have been transferred to the new BD location.
	 */
	smp_wmb();

	src_map->data = NULL;
}

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.