static void tg3_phy_copper_begin(struct tg3 *tp)
{
	if (tp->link_config.autoneg == AUTONEG_ENABLE ||
	    (tp->phy_flags & TG3_PHYFLG_IS_LOW_POWER)) {
		u32 adv, fc;

		if (tp->phy_flags & TG3_PHYFLG_IS_LOW_POWER) {
			adv = ADVERTISED_10baseT_Half |
			      ADVERTISED_10baseT_Full;
			if (tg3_flag(tp, WOL_SPEED_100MB))
				adv |= ADVERTISED_100baseT_Half |
				       ADVERTISED_100baseT_Full;

			fc = FLOW_CTRL_TX | FLOW_CTRL_RX;
		} else {
			adv = tp->link_config.advertising;
			if (tp->phy_flags & TG3_PHYFLG_10_100_ONLY)
				adv &= ~(ADVERTISED_1000baseT_Half |
					 ADVERTISED_1000baseT_Full);

			fc = tp->link_config.flowctrl;
		}

		tg3_phy_autoneg_cfg(tp, adv, fc);

		tg3_writephy(tp, MII_BMCR,
			     BMCR_ANENABLE | BMCR_ANRESTART);
	} else {
		int i;
		u32 bmcr, orig_bmcr;

		tp->link_config.active_speed = tp->link_config.speed;
		tp->link_config.active_duplex = tp->link_config.duplex;

		if (tg3_asic_rev(tp) == ASIC_REV_5714) {
			/* With autoneg disabled, 5715 only links up when the
			 * advertisement register has the configured speed
			 * enabled.
			 */
			tg3_writephy(tp, MII_ADVERTISE, ADVERTISE_ALL);
		}

		bmcr = 0;
		switch (tp->link_config.speed) {
		default:
		case SPEED_10:
			break;

		case SPEED_100:
			bmcr |= BMCR_SPEED100;
			break;

		case SPEED_1000:
			bmcr |= BMCR_SPEED1000;
			break;
		}

		if (tp->link_config.duplex == DUPLEX_FULL)
			bmcr |= BMCR_FULLDPLX;

		if (!tg3_readphy(tp, MII_BMCR, &orig_bmcr) &&
		    (bmcr != orig_bmcr)) {
			tg3_writephy(tp, MII_BMCR, BMCR_LOOPBACK);
			for (i = 0; i < 1500; i++) {
				u32 tmp;

				udelay(10);
				if (tg3_readphy(tp, MII_BMSR, &tmp) ||
				    tg3_readphy(tp, MII_BMSR, &tmp))
					continue;
				if (!(tmp & BMSR_LSTATUS)) {
					udelay(40);
					break;
				}
			}
			tg3_writephy(tp, MII_BMCR, bmcr);
			udelay(40);
		}
	}
}

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.