static int cqspi_command_read(struct spi_nor *nor,
			      const u8 *txbuf, const unsigned n_tx,
			      u8 *rxbuf, const unsigned n_rx)
{
	struct cqspi_flash_pdata *f_pdata = nor->priv;
	struct cqspi_st *cqspi = f_pdata->cqspi;
	void __iomem *reg_base = cqspi->iobase;
	unsigned int rdreg;
	unsigned int reg;
	unsigned int read_len;
	int status;

	if (!n_rx || n_rx > CQSPI_STIG_DATA_LEN_MAX || !rxbuf) {
		dev_err(nor->dev, "Invalid input argument, len %d rxbuf 0x%p\n",
			n_rx, rxbuf);
		return -EINVAL;
	}

	reg = txbuf[0] << CQSPI_REG_CMDCTRL_OPCODE_LSB;

	rdreg = cqspi_calc_rdreg(nor, txbuf[0]);
	writel(rdreg, reg_base + CQSPI_REG_RD_INSTR);

	reg |= (0x1 << CQSPI_REG_CMDCTRL_RD_EN_LSB);

	/* 0 means 1 byte. */
	reg |= (((n_rx - 1) & CQSPI_REG_CMDCTRL_RD_BYTES_MASK)
		<< CQSPI_REG_CMDCTRL_RD_BYTES_LSB);
	status = cqspi_exec_flash_cmd(cqspi, reg);
	if (status)
		return status;

	reg = readl(reg_base + CQSPI_REG_CMDREADDATALOWER);

	/* Put the read value into rx_buf */
	read_len = (n_rx > 4) ? 4 : n_rx;
	memcpy(rxbuf, &reg, read_len);
	rxbuf += read_len;

	if (n_rx > 4) {
		reg = readl(reg_base + CQSPI_REG_CMDREADDATAUPPER);

		read_len = n_rx - read_len;
		memcpy(rxbuf, &reg, read_len);
	}

	return 0;
}

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.