static void qeth_idx_write_cb(struct qeth_channel *channel,
		struct qeth_cmd_buffer *iob)
{
	struct qeth_card *card;
	__u16 temp;

	QETH_DBF_TEXT(SETUP , 2, "idxwrcb");

	if (channel->state == CH_STATE_DOWN) {
		channel->state = CH_STATE_ACTIVATING;
		goto out;
	}
	card = CARD_FROM_CDEV(channel->ccwdev);

	if (!(QETH_IS_IDX_ACT_POS_REPLY(iob->data))) {
		if (QETH_IDX_ACT_CAUSE_CODE(iob->data) == QETH_IDX_ACT_ERR_EXCL)
			dev_err(&card->write.ccwdev->dev,
				"The adapter is used exclusively by another "
				"host\n");
		else
			QETH_DBF_MESSAGE(2, "%s IDX_ACTIVATE on write channel:"
				" negative reply\n",
				dev_name(&card->write.ccwdev->dev));
		goto out;
	}
	memcpy(&temp, QETH_IDX_ACT_FUNC_LEVEL(iob->data), 2);
	if ((temp & ~0x0100) != qeth_peer_func_level(card->info.func_level)) {
		QETH_DBF_MESSAGE(2, "%s IDX_ACTIVATE on write channel: "
			"function level mismatch (sent: 0x%x, received: "
			"0x%x)\n", dev_name(&card->write.ccwdev->dev),
			card->info.func_level, temp);
		goto out;
	}
	channel->state = CH_STATE_UP;
out:
	qeth_release_buffer(channel, iob);
}

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.