Re: [PATCH v4] iio: adc: ad4030: fix invalid oversampling_ratio validation

[Nuno Sá]

On Tue, Sep 01, 2026 at 02:08:44PM +0300, Andy Shevchenko wrote:
> On Tue, Sep 01, 2026 at 11:42:43AM +0100, Salah Triki wrote:
> > In ad4030_set_avg_frame_len(), the logarithm is calculated before input
> > validation. Passing zero or negative values leads to an undefined result
> > from ilog2().
> > 
> > Validate that the input is strictly positive prior to computing its
> > logarithm to ensure only valid values are processed.
> 
> ...
> 
> > -	if (avg_val < 0 || avg_val > ad4030_average_modes[last_avg_idx])
> > +	if (avg_val <= 0 || avg_val > ad4030_average_modes[last_avg_idx])
> >  		return -EINVAL;
> 
> I still find '<= 0' confusing. Why not check against 1?
> And I would rather see an additional comment.

I realize here it does not matter much but I tend to agree that the correct
check is against 1

> 
> What about
> 
> 	/* Reject unsupported modes */
> 	if (avg_val > ad4030_average_modes[last_avg_idx])
> 		return -EINVAL;
> 
> 	/* Avoid invalid values for logarithm since it's undefined */
> 	if (avg_val < 1)
> // In this case, when condition is split, if (avg_val <= 0) is also possible
> 		return -EINVAL;
> 

Also tend to agree with the above but no strong feeling.

- Nuno Sá

> > +	avg_log2 = ilog2(avg_val);
> 
> -- 
> With Best Regards,
> Andy Shevchenko
> 
>