[alsa-devel] [PATCH 1/2] ASoC: soc-generic-dmaengine-pcm: Fix error handling

[Lars-Peter Clausen]

On 02/22/2018 08:02 PM, Fabio Estevam wrote:
> From: Fabio Estevam <fabio.estevam at nxp.com>
> 
> When dmaengine_pcm_request_chan_of() fails it should release
> the previously acquired resources, which in this case is to
> call kfree(pcm), so jump to the correct point in the error
> path.
> 
> Signed-off-by: Fabio Estevam <fabio.estevam at nxp.com>

This creates a resource leak. dmaengine_pcm_request_chan_of() requests both
transmit and receive channels. It might return with an error if one of them
fails, but the other one succeeded. In this case we need to call
dmaengine_pcm_release_chan() to free the requested channel.

> ---
>  sound/soc/soc-generic-dmaengine-pcm.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c
> index 768247f..32ea16d 100644
> --- a/sound/soc/soc-generic-dmaengine-pcm.c
> +++ b/sound/soc/soc-generic-dmaengine-pcm.c
> @@ -450,7 +450,7 @@ int snd_dmaengine_pcm_register(struct device *dev,
>  
>  	ret = dmaengine_pcm_request_chan_of(pcm, dev, config);
>  	if (ret)
> -		goto err_free_dma;
> +		goto err_free_pcm;
>  
>  	ret = snd_soc_add_component(dev, &pcm->component,
>  				    &dmaengine_pcm_component, NULL, 0);
> @@ -461,6 +461,7 @@ int snd_dmaengine_pcm_register(struct device *dev,
>  
>  err_free_dma:
>  	dmaengine_pcm_release_chan(pcm);
> +err_free_pcm:
>  	kfree(pcm);
>  	return ret;
>  }
>