Re: [alsa-devel] [PATCH] ASoC: soc-core: Fix null pointer dereference in soc_find_component

[Pierre-Louis Bossart]

On 1/11/19 2:14 AM, Rohit kumar wrote:
> From: Ajit Pandey <ajitp@xxxxxxxxxxxxxx>
>
> soc_find_component() may lead to null pointer exception if both
> arguments i.e of_node and name is NULL. Add NULL check before
> calling soc_find_component(). Also fix some typos.

Thanks for the overnight fix. This update fixes the issue on my Skylake 
XPS13 test device (blind testing since I don't understand what the code 
does).

Tested-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>

> Fixes: 8780cf1142a5 ("ASoC: soc-core: defer card probe until all component is added to list")
> Reported-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
> Signed-off-by: Ajit Pandey <ajitp@xxxxxxxxxxxxxx>
> Signed-off-by: Rohit kumar <rohitkr@xxxxxxxxxxxxxx>
> ---
>   sound/soc/soc-core.c | 15 +++++++++------
>   1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
> index 0934b36..df05fb8 100644
> --- a/sound/soc/soc-core.c
> +++ b/sound/soc/soc-core.c
> @@ -1131,11 +1131,13 @@ static int soc_init_dai_link(struct snd_soc_card *card,
>   	}
>   
>   	/*
> -	 * Defer card registartion if platform dai component is not added to
> +	 * Defer card registration if platform dai component is not added to
>   	 * component list.
>   	 */
> -	if (!soc_find_component(link->platform->of_node, link->platform->name))
> -		return -EPROBE_DEFER;
> +	if (link->platform->of_node || link->platform->name)
> +		if (!soc_find_component(link->platform->of_node,
> +					link->platform->name))
> +			return -EPROBE_DEFER;
>   
>   	/*
>   	 * CPU device may be specified by either name or OF node, but
> @@ -1150,11 +1152,12 @@ static int soc_init_dai_link(struct snd_soc_card *card,
>   	}
>   
>   	/*
> -	 * Defer card registartion if cpu dai component is not added to
> +	 * Defer card registration if cpu dai component is not added to
>   	 * component list.
>   	 */
> -	if (!soc_find_component(link->cpu_of_node, link->cpu_name))
> -		return -EPROBE_DEFER;
> +	if (link->cpu_of_node || link->cpu_name)
> +		if (!soc_find_component(link->cpu_of_node, link->cpu_name))
> +			return -EPROBE_DEFER;
>   
>   	/*
>   	 * At least one of CPU DAI name or CPU device name/node must be