FAILED: patch "[PATCH] iio: adc: stm32-adc: fix possible division by zero in" failed to apply to 6.6-stable tree

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x c5de6a6f855fdcf1e0ea549fb227a316db51c405
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026100606-vitally-sprain-dbc6@gregkh' --subject-prefix 'PATCH 6.6.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From c5de6a6f855fdcf1e0ea549fb227a316db51c405 Mon Sep 17 00:00:00 2001
From: Fabrice Gasnier <[email protected]>
Date: Wed, 16 Sep 2026 19:15:04 +0200
Subject: [PATCH] iio: adc: stm32-adc: fix possible division by zero in
processed channel

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 the converted value is zero, e.g. the Vrefint channel, this should be considered as invalid in all cases.

index b77f39f305d8..90f0e257e6d1 100644
@@ -1608,11 +1608,16 @@ static int stm32_adc_read_raw(struct iio_dev *indio_dev,
 			ret = stm32_adc_single_conv(indio_dev, chan, val);
 		else
 			ret = -EINVAL;
-
-		if (mask == IIO_CHAN_INFO_PROCESSED)
-			*val = STM32_ADC_VREFINT_VOLTAGE * adc->vrefint.vrefint_cal / *val;
-
 		iio_device_release_direct(indio_dev);
+		if (ret < 0)
+			return ret;
+
+		if (mask == IIO_CHAN_INFO_PROCESSED) {
+			if (*val == 0)
+				return -EINVAL;
+			*val = STM32_ADC_VREFINT_VOLTAGE * adc->vrefint.vrefint_cal / *val;
+		}
+
 		return ret;
 
 	case IIO_CHAN_INFO_SCALE:

From: Fabrice Gasnier <[email protected]>

[ Upstream commit c5de6a6f855fdcf1e0ea549fb227a316db51c405 ]

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 the converted value is zero, e.g. the Vrefint channel, this should be considered as invalid in all cases.

---
 drivers/iio/adc/stm32-adc.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

index 2ce521871bdcf..3b78581c5e785 100644
@@ -1478,11 +1478,16 @@ static int stm32_adc_read_raw(struct iio_dev *indio_dev,
 			ret = stm32_adc_single_conv(indio_dev, chan, val);
 		else
 			ret = -EINVAL;
+		iio_device_release_direct_mode(indio_dev);
+		if (ret < 0)
+			return ret;
 
-		if (mask == IIO_CHAN_INFO_PROCESSED)
+		if (mask == IIO_CHAN_INFO_PROCESSED) {
+			if (*val == 0)
+				return -EINVAL;
 			*val = STM32_ADC_VREFINT_VOLTAGE * adc->vrefint.vrefint_cal / *val;
+		}
 
-		iio_device_release_direct_mode(indio_dev);
 		return ret;
 
 	case IIO_CHAN_INFO_SCALE:

2.53.0