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From: Andy Shevchenko <andriy.shevchenko@intel.com>
To: Salah Triki <salah.triki@gmail.com>
Cc: "Nuno Sá" <nuno.sa@analog.com>,
	"Michael Hennerich" <Michael.Hennerich@analog.com>,
	"Esteban Blanc" <eblanc@baylibre.com>,
	"Jonathan Cameron" <jic23@kernel.org>,
	"David Lechner" <dlechner@baylibre.com>,
	"Andy Shevchenko" <andy@kernel.org>,
	linux@analog.com, linux-iio@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4] iio: adc: ad4030: fix invalid oversampling_ratio validation
Date: Tue, 1 Sep 2026 14:08:44 +0300	[thread overview]
Message-ID: <apayPCk4ln_Hh_Bb@ashevche-desk.local> (raw)
In-Reply-To: <20260901104243.48732-1-salah.triki@gmail.com>

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.

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;

> +	avg_log2 = ilog2(avg_val);

-- 
With Best Regards,
Andy Shevchenko



  reply	other threads:[~2026-09-01 11:08 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-01 10:42 [PATCH v4] iio: adc: ad4030: fix invalid oversampling_ratio validation Salah Triki
2026-09-01 11:08 ` Andy Shevchenko [this message]
2026-09-01 14:38   ` Nuno Sá

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