Re: [PATCH] iio: adc: ad_sigma_delta: Fix use of uninitialized variable status_pos

[Purva Yeshi]

On 10/04/25 16:39, Nuno Sá wrote:
> Hi Purva,
>
> Thanks for your patch... See below
> On Thu, 2025-04-10 at 01:31 +0530, Purva Yeshi wrote:
> > Fix Smatch-detected error:
> > drivers/iio/adc/ad_sigma_delta.c:604 ad_sd_trigger_handler() error:
> > uninitialized symbol 'status_pos'.
> >
> > The variable `status_pos` was only initialized in specific switch cases
> > (1, 2, 3, 4), which could leave it uninitialized if `reg_size` had an
> > unexpected value.
> >
> > Fix by validating `reg_size` before the switch block. If it’s not
> > one of the expected values, return early and log an error. This ensures
> > `status_pos` is always initialized before use and prevents undefined
> > behavior.
> >
> > Signed-off-by: Purva Yeshi <purvayeshi550@xxxxxxxxx>
> > ---
> >   drivers/iio/adc/ad_sigma_delta.c | 5 +++++
> >   1 file changed, 5 insertions(+)
> >
> > diff --git a/drivers/iio/adc/ad_sigma_delta.c
> > b/drivers/iio/adc/ad_sigma_delta.c
> > index 6c37f8e21120..d3b59d90b728 100644
> > --- a/drivers/iio/adc/ad_sigma_delta.c
> > +++ b/drivers/iio/adc/ad_sigma_delta.c
> > @@ -568,6 +568,11 @@ static irqreturn_t ad_sd_trigger_handler(int irq, void
> > *p)
> >   	else
> >   		transfer_size = reg_size;
> >   
> > +	if (reg_size != 1 && reg_size != 2 && reg_size != 3 && reg_size != 4)
> > {
> > +		dev_err(&indio_dev->dev, "Unsupported reg_size: %u\n",
> > reg_size);
> > +		return IRQ_HANDLED;
> > +	}
> > +
>
> Use the switch case for this. Add a default branch for the invalid case. You
> should also use dev_err_ratelimited() and instead of 'return IRQ_HANDLED', do
> 'goto irq_handled'.
>
> Thx!
> - Nuno Sá

Hi Nuno,

Thank you for the review and guidance.

I’ve updated the patch to address your suggestions and will send the 
next version shortly.

Best regards,
Purva

> >   	switch (reg_size) {
> >   	case 4:
> >   	case 2: