Re: [PATCH] iio: addac: ad74115: Fix use of uninitialized variable rate

[Purva Yeshi]

On 10/04/25 20:21, David Lechner wrote:
> On 4/9/25 3:29 PM, Purva Yeshi wrote:
> > Fix Smatch-detected error:
> > drivers/iio/addac/ad74115.c:823 _ad74115_get_adc_code() error:
> > uninitialized symbol 'rate'.
> >
> > The variable rate was declared but not given any value before being used
> > in a division. If the code reached that point without setting rate, it
> > would cause unpredictable behavior.
> >
> > Declare and initialize 'rate' to zero inside the 'else' block where it is
> > used. This ensures 'rate' is always initialized before being passed to
> > DIV_ROUND_CLOSEST.
> >
> > Signed-off-by: Purva Yeshi <purvayeshi550@xxxxxxxxx>
> > ---
> >   drivers/iio/addac/ad74115.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/iio/addac/ad74115.c b/drivers/iio/addac/ad74115.c
> > index a7e480f2472d..26770c68e5fa 100644
> > --- a/drivers/iio/addac/ad74115.c
> > +++ b/drivers/iio/addac/ad74115.c
> > @@ -814,7 +814,7 @@ static int _ad74115_get_adc_code(struct ad74115_state *st,
> >   			return -ETIMEDOUT;
> >   	} else {
> >   		unsigned int regval, wait_time;
> > -		int rate;
> > +		int rate = 0;
> >   
> >   		ret = ad74115_get_adc_rate(st, channel, &rate);
> >   		if (ret < 0)
>
> I don't see how rate could be used uninitialized since we are
> returning the error if ad74115_get_adc_rate() fails.
>
> Also, initializing to 0 would then cause a divide by 0 error
> if that value was actually used later in the code.

Hi,

Thank you for the review and explanation.

Understood — since there's a risk of misuse later (like divide-by-zero), 
it's best to leave it as is.

Best regards,
Purva

>