In the ad7780_write_raw() , val2 can be zero, which might lead to a
division by zero error in DIV_ROUND_CLOSEST(). The ad7780_write_raw()
is based on iio_info's write_raw. While val is explicitly declared that
can be zero (in read mode), val2 is not specified to be non-zero.

Fixes: 9085daa4abcc ("staging: iio: ad7780: add gain & filter gpio support")
Cc: <stable@vger.kernel.org>
Signed-off-by: Zicheng Qu <quzicheng@huawei.com>
---
 drivers/iio/adc/ad7780.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/adc/ad7780.c b/drivers/iio/adc/ad7780.c
index e9b0c577c9cc..8ccb74f47030 100644
--- a/drivers/iio/adc/ad7780.c
+++ b/drivers/iio/adc/ad7780.c
@@ -152,7 +152,7 @@ static int ad7780_write_raw(struct iio_dev *indio_dev,
 
 	switch (m) {
 	case IIO_CHAN_INFO_SCALE:
-		if (val != 0)
+		if (val != 0 || val2 == 0)
 			return -EINVAL;
 
 		vref = st->int_vref_mv * 1000000LL;
-- 
2.34.1

On Mon, 28 Oct 2024 14:20:27 +0000
Zicheng Qu <quzicheng@huawei.com> wrote:

> In the ad7780_write_raw() , val2 can be zero, which might lead to a
> division by zero error in DIV_ROUND_CLOSEST(). The ad7780_write_raw()
> is based on iio_info's write_raw. While val is explicitly declared that
> can be zero (in read mode), val2 is not specified to be non-zero.
> 
> Fixes: 9085daa4abcc ("staging: iio: ad7780: add gain & filter gpio support")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Zicheng Qu <quzicheng@huawei.com>
Applied to the fixes-togreg branch of iio.git.

I might end up dragging this in to my queue for the coming merge window
if I don't get time to do another fixes pull request in the next few
days.

Jonathan

> ---
>  drivers/iio/adc/ad7780.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/adc/ad7780.c b/drivers/iio/adc/ad7780.c
> index e9b0c577c9cc..8ccb74f47030 100644
> --- a/drivers/iio/adc/ad7780.c
> +++ b/drivers/iio/adc/ad7780.c
> @@ -152,7 +152,7 @@ static int ad7780_write_raw(struct iio_dev *indio_dev,
>  
>  	switch (m) {
>  	case IIO_CHAN_INFO_SCALE:
> -		if (val != 0)
> +		if (val != 0 || val2 == 0)
>  			return -EINVAL;
>  
>  		vref = st->int_vref_mv * 1000000LL;

Gentle ping.