static void tg3_serdes_parallel_detect(struct tg3 *tp)
{
	if (tp->serdes_counter) {
		/* Give autoneg time to complete. */
		tp->serdes_counter--;
		return;
	}

	if (!tp->link_up &&
	    (tp->link_config.autoneg == AUTONEG_ENABLE)) {
		u32 bmcr;

		tg3_readphy(tp, MII_BMCR, &bmcr);
		if (bmcr & BMCR_ANENABLE) {
			u32 phy1, phy2;

			/* Select shadow register 0x1f */
			tg3_writephy(tp, MII_TG3_MISC_SHDW, 0x7c00);
			tg3_readphy(tp, MII_TG3_MISC_SHDW, &phy1);

			/* Select expansion interrupt status register */
			tg3_writephy(tp, MII_TG3_DSP_ADDRESS,
					 MII_TG3_DSP_EXP1_INT_STAT);
			tg3_readphy(tp, MII_TG3_DSP_RW_PORT, &phy2);
			tg3_readphy(tp, MII_TG3_DSP_RW_PORT, &phy2);

			if ((phy1 & 0x10) && !(phy2 & 0x20)) {
				/* We have signal detect and not receiving
				 * config code words, link is up by parallel
				 * detection.
				 */

				bmcr &= ~BMCR_ANENABLE;
				bmcr |= BMCR_SPEED1000 | BMCR_FULLDPLX;
				tg3_writephy(tp, MII_BMCR, bmcr);
				tp->phy_flags |= TG3_PHYFLG_PARALLEL_DETECT;
			}
		}
	} else if (tp->link_up &&
		   (tp->link_config.autoneg == AUTONEG_ENABLE) &&
		   (tp->phy_flags & TG3_PHYFLG_PARALLEL_DETECT)) {
		u32 phy2;

		/* Select expansion interrupt status register */
		tg3_writephy(tp, MII_TG3_DSP_ADDRESS,
				 MII_TG3_DSP_EXP1_INT_STAT);
		tg3_readphy(tp, MII_TG3_DSP_RW_PORT, &phy2);
		if (phy2 & 0x20) {
			u32 bmcr;

			/* Config code words received, turn on autoneg. */
			tg3_readphy(tp, MII_BMCR, &bmcr);
			tg3_writephy(tp, MII_BMCR, bmcr | BMCR_ANENABLE);

			tp->phy_flags &= ~TG3_PHYFLG_PARALLEL_DETECT;

		}
	}
}

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.