static int tg3_rx_prodring_xfer(struct tg3 *tp,
				struct tg3_rx_prodring_set *dpr,
				struct tg3_rx_prodring_set *spr)
{
	u32 si, di, cpycnt, src_prod_idx;
	int i, err = 0;

	while (1) {
		src_prod_idx = spr->rx_std_prod_idx;

		/* Make sure updates to the rx_std_buffers[] entries and the
		 * standard producer index are seen in the correct order.
		 */
		smp_rmb();

		if (spr->rx_std_cons_idx == src_prod_idx)
			break;

		if (spr->rx_std_cons_idx < src_prod_idx)
			cpycnt = src_prod_idx - spr->rx_std_cons_idx;
		else
			cpycnt = tp->rx_std_ring_mask + 1 -
				 spr->rx_std_cons_idx;

		cpycnt = min(cpycnt,
			     tp->rx_std_ring_mask + 1 - dpr->rx_std_prod_idx);

		si = spr->rx_std_cons_idx;
		di = dpr->rx_std_prod_idx;

		for (i = di; i < di + cpycnt; i++) {
			if (dpr->rx_std_buffers[i].data) {
				cpycnt = i - di;
				err = -ENOSPC;
				break;
			}
		}

		if (!cpycnt)
			break;

		/* Ensure that updates to the rx_std_buffers ring and the
		 * shadowed hardware producer ring from tg3_recycle_skb() are
		 * ordered correctly WRT the skb check above.
		 */
		smp_rmb();

		memcpy(&dpr->rx_std_buffers[di],
		       &spr->rx_std_buffers[si],
		       cpycnt * sizeof(struct ring_info));

		for (i = 0; i < cpycnt; i++, di++, si++) {
			struct tg3_rx_buffer_desc *sbd, *dbd;
			sbd = &spr->rx_std[si];
			dbd = &dpr->rx_std[di];
			dbd->addr_hi = sbd->addr_hi;
			dbd->addr_lo = sbd->addr_lo;
		}

		spr->rx_std_cons_idx = (spr->rx_std_cons_idx + cpycnt) &
				       tp->rx_std_ring_mask;
		dpr->rx_std_prod_idx = (dpr->rx_std_prod_idx + cpycnt) &
				       tp->rx_std_ring_mask;
	}

	while (1) {
		src_prod_idx = spr->rx_jmb_prod_idx;

		/* Make sure updates to the rx_jmb_buffers[] entries and
		 * the jumbo producer index are seen in the correct order.
		 */
		smp_rmb();

		if (spr->rx_jmb_cons_idx == src_prod_idx)
			break;

		if (spr->rx_jmb_cons_idx < src_prod_idx)
			cpycnt = src_prod_idx - spr->rx_jmb_cons_idx;
		else
			cpycnt = tp->rx_jmb_ring_mask + 1 -
				 spr->rx_jmb_cons_idx;

		cpycnt = min(cpycnt,
			     tp->rx_jmb_ring_mask + 1 - dpr->rx_jmb_prod_idx);

		si = spr->rx_jmb_cons_idx;
		di = dpr->rx_jmb_prod_idx;

		for (i = di; i < di + cpycnt; i++) {
			if (dpr->rx_jmb_buffers[i].data) {
				cpycnt = i - di;
				err = -ENOSPC;
				break;
			}
		}

		if (!cpycnt)
			break;

		/* Ensure that updates to the rx_jmb_buffers ring and the
		 * shadowed hardware producer ring from tg3_recycle_skb() are
		 * ordered correctly WRT the skb check above.
		 */
		smp_rmb();

		memcpy(&dpr->rx_jmb_buffers[di],
		       &spr->rx_jmb_buffers[si],
		       cpycnt * sizeof(struct ring_info));

		for (i = 0; i < cpycnt; i++, di++, si++) {
			struct tg3_rx_buffer_desc *sbd, *dbd;
			sbd = &spr->rx_jmb[si].std;
			dbd = &dpr->rx_jmb[di].std;
			dbd->addr_hi = sbd->addr_hi;
			dbd->addr_lo = sbd->addr_lo;
		}

		spr->rx_jmb_cons_idx = (spr->rx_jmb_cons_idx + cpycnt) &
				       tp->rx_jmb_ring_mask;
		dpr->rx_jmb_prod_idx = (dpr->rx_jmb_prod_idx + cpycnt) &
				       tp->rx_jmb_ring_mask;
	}

	return err;
}

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.