static int tg3_ape_lock(struct tg3 *tp, int locknum)
{
	int i, off;
	int ret = 0;
	u32 status, req, gnt, bit;

	if (!tg3_flag(tp, ENABLE_APE))
		return 0;

	switch (locknum) {
	case TG3_APE_LOCK_GPIO:
		if (tg3_asic_rev(tp) == ASIC_REV_5761)
			return 0;
	case TG3_APE_LOCK_GRC:
	case TG3_APE_LOCK_MEM:
		if (!tp->pci_fn)
			bit = APE_LOCK_REQ_DRIVER;
		else
			bit = 1 << tp->pci_fn;
		break;
	case TG3_APE_LOCK_PHY0:
	case TG3_APE_LOCK_PHY1:
	case TG3_APE_LOCK_PHY2:
	case TG3_APE_LOCK_PHY3:
		bit = APE_LOCK_REQ_DRIVER;
		break;
	default:
		return -EINVAL;
	}

	if (tg3_asic_rev(tp) == ASIC_REV_5761) {
		req = TG3_APE_LOCK_REQ;
		gnt = TG3_APE_LOCK_GRANT;
	} else {
		req = TG3_APE_PER_LOCK_REQ;
		gnt = TG3_APE_PER_LOCK_GRANT;
	}

	off = 4 * locknum;

	tg3_ape_write32(tp, req + off, bit);

	/* Wait for up to 1 millisecond to acquire lock. */
	for (i = 0; i < 100; i++) {
		status = tg3_ape_read32(tp, gnt + off);
		if (status == bit)
			break;
		udelay(10);
	}

	if (status != bit) {
		/* Revoke the lock request. */
		tg3_ape_write32(tp, gnt + off, bit);
		ret = -EBUSY;
	}

	return ret;
}

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.