Re: [PATCH v1 4/7] ASoC: pxa: Replace dma_request_slave_channel() by dma_request_chan()

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] UAPI: -EPROBE_DEFER leaked to user-space open() via pxa2xx_pcm_open()
--

commit 44587eacc45895505692b413ada6ab4975034283
Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

ASoC: pxa: Replace dma_request_slave_channel() by dma_request_chan()

This commit replaces the deprecated dma_request_slave_channel() with
dma_request_chan().

> diff --git a/sound/soc/pxa/pxa2xx-pcm-lib.c b/sound/soc/pxa/pxa2xx-pcm-lib.c
> index 88a9d32263021..0ccf88aa11389 100644
> --- a/sound/soc/pxa/pxa2xx-pcm-lib.c
> +++ b/sound/soc/pxa/pxa2xx-pcm-lib.c
[ ... ]
> @@ -107,9 +108,12 @@ static int pxa2xx_pcm_open(struct snd_pcm_substream *substream)
>  	if (ret < 0)
>  		return ret;
>  
> -	return snd_dmaengine_pcm_open(
> -		substream, dma_request_slave_channel(snd_soc_rtd_to_cpu(rtd, 0)->dev,
> -						     dma_params->chan_name));
> +	chan = dma_request_chan(snd_soc_rtd_to_cpu(rtd, 0)->dev, dma_params->chan_name);
> +	ret = PTR_ERR_OR_ZERO(chan);
> +	if (ret)
> +		return ret;

[Severity: Medium]
Will this leak the kernel-internal -EPROBE_DEFER error code to user-space?

If dma_request_chan() fails because the DMA driver isn't loaded yet, it
can return -EPROBE_DEFER.  Since pxa2xx_pcm_open() returns this directly, 
the -EPROBE_DEFER error code would be passed up to snd_pcm_open() and 
returned to the user-space application calling open() on the ALSA device.

In the old code, dma_request_slave_channel() returned NULL on failure,
and snd_dmaengine_pcm_open() mapped that NULL to -ENXIO. Could we map the
error here to a standard user-facing error like -ENXIO when 
dma_request_chan() fails?

> +
> +	return snd_dmaengine_pcm_open(substream, chan);
>  }
>  
>  static int pxa2xx_pcm_close(struct snd_pcm_substream *substream)

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260915100931.3593242-1-andriy.shevchenko@linux.intel.com?part=4