Re: [PATCH v2 1/3] ASoC: sunxi: sun4i-spdif: Use guard() for spin locks

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [Critical] If `regmap_read()` fails in `sun4i_spdif_get_status()`, the local variable `reg` is left uninitialized, leading to a kernel stack information leak.
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commit b943afeae6523774115b9e6d838ae64e650c95c5
Author: bui duc phuc <phucduc.bui@gmail.com>

ASoC: sunxi: sun4i-spdif: Use guard() for spin locks

This commit refactors the sun4i-spdif driver to use the scoped_guard() macro
for managing spin locks. The changes are intended as refactoring only, with
no functional changes to the driver's behavior.

> diff --git a/sound/soc/sunxi/sun4i-spdif.c b/sound/soc/sunxi/sun4i-spdif.c
> index c2ec19437cd7a..89eccc83a1301 100644
> --- a/sound/soc/sunxi/sun4i-spdif.c
> +++ b/sound/soc/sunxi/sun4i-spdif.c
> @@ -427,24 +427,21 @@ static int sun4i_spdif_get_status(struct snd_kcontrol *kcontrol,
>  	struct snd_soc_dai *cpu_dai = snd_kcontrol_chip(kcontrol);
>  	struct sun4i_spdif_dev *host = snd_soc_dai_get_drvdata(cpu_dai);
>  	u8 *status = ucontrol->value.iec958.status;
> -	unsigned long flags;
>  	unsigned int reg;
>  
> -	spin_lock_irqsave(&host->lock, flags);
> +	scoped_guard(spinlock_irqsave, &host->lock) {
> +		regmap_read(host->regmap, SUN4I_SPDIF_TXCHSTA0, &reg);

[Severity: Critical]
This is a pre-existing issue, but does this leak uninitialized kernel stack
memory to userspace?

The regmap_read() function can fail and return an error code without modifying
the reg variable. Since the return value isn't checked, the uninitialized
contents of reg are unpacked into the status array:

		status[0] = reg & 0xff;
		status[1] = (reg >> 8) & 0xff;
		status[2] = (reg >> 16) & 0xff;
		status[3] = (reg >> 24) & 0xff;

This array is subsequently copied back to userspace by the ALSA control
subsystem.

Should the return value of regmap_read() be checked, and an error returned
if it fails?

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260522095401.72915-1-phucduc.bui@gmail.com?part=1