Re: [PATCH] iio: adc: stm32-adc: fix possible division by zero in processed channel

On Tue, Sep 15, 2026 at 06:10:40PM +0200, Fabrice Gasnier wrote:

In case the conversion has failed or returned zero, processing *val
can lead to a division by zero.
Need to check for errors, or converted value is zero, before processing
the data.
In case converted value is zero, e.g. the Vrefint channel, this should
be considered as invalid in all case.

Something went very wrong with the indentation of the above.

...

-		if (mask == IIO_CHAN_INFO_PROCESSED)
-			*val = STM32_ADC_VREFINT_VOLTAGE * adc->vrefint.vrefint_cal / *val;
+		if (mask == IIO_CHAN_INFO_PROCESSED) {
+			if (ret >= 0 && *val)
+				*val = STM32_ADC_VREFINT_VOLTAGE * adc->vrefint.vrefint_cal / *val;
+			else
+				ret = ret < 0 ? ret : -EINVAL;
+		}

Reuse of the *val makes code harder to follow. Add a temporary variable for
this and do something like this (also note other simplifications)

		tmp_choose_good_name = *val;
		...
		if (mask == IIO_CHAN_INFO_PROCESSED) {
			if (ret < 0)
				return ret;
			if (tmp == 0)
				return -EINVAL;

			*val = STM32_ADC_VREFINT_VOLTAGE * adc->vrefint.vrefint_cal / tmp;
		}

 		iio_device_release_direct(indio_dev);
 		return ret;

-- 
With Best Regards,
Andy Shevchenko