[alsa-devel] [PATCH] ASoC: cht_bsw_max98090_ti: Fix NULL pointer dereference while accessing jack

[Pierre-Louis Bossart]

On 10/12/17 2:28 PM, Guenter Roeck wrote:
> From: Guenter Roeck <groeck at chromium.org>
> 
> Commit f2ed6b07645e ("ASoC: Make aux_dev more like a generic component")
> caused a regression on this driver, since now a kernel oops is seen
> when the driver is loaded, or more specifically when
> ts3a227e_enable_jack_detect() is called.
> 
> That commit changed the probing of aux_devs before checking new DAI links,
> so cht_max98090_headset_init is now called before cht_codec_init. The
> kernel crashes due a NULL pointer dereference in cht_max98090_headset_init
> since there is a call that tries to access the jack pointer which has not
> been allocated yet.
> 
> This patch moves the new jack object creation from cht_codec_init to
> cht_max98090_headset_init, making sure the jack is created before is
> accessed.
> 
> Also see upstream commit 5f22449344d9 ("ASoC: rockchip-max98090: Fix NULL
> pointer dereference while accessing to jack.") for a similar fix in the
> rockchip-max98090 driver.

Are you sure this isn't fixed already? Some of the changes suggested 
have already been applied by Mark Brown on his for-next branch.

> 
> Fixes: f2ed6b07645e ("ASoC: Make aux_dev more like a generic component")
> Cc: Mengdong Lin <mengdong.lin at linux.intel.com>
> Signed-off-by: Guenter Roeck <groeck at chromium.org>
> ---
>   sound/soc/intel/boards/cht_bsw_max98090_ti.c | 55 ++++++++++++++--------------
>   1 file changed, 27 insertions(+), 28 deletions(-)
> 
> diff --git a/sound/soc/intel/boards/cht_bsw_max98090_ti.c b/sound/soc/intel/boards/cht_bsw_max98090_ti.c
> index 20755ecc7f9e..c1518db7bb61 100644
> --- a/sound/soc/intel/boards/cht_bsw_max98090_ti.c
> +++ b/sound/soc/intel/boards/cht_bsw_max98090_ti.c
> @@ -111,37 +111,12 @@ static struct notifier_block cht_jack_nb = {
>   
>   static int cht_codec_init(struct snd_soc_pcm_runtime *runtime)
>   {
> -	int ret;
> -	int jack_type;
>   	struct cht_mc_private *ctx = snd_soc_card_get_drvdata(runtime->card);
> -	struct snd_soc_jack *jack = &ctx->jack;
> -
> -	/**
> -	* TI supports 4 butons headset detection
> -	* KEY_MEDIA
> -	* KEY_VOICECOMMAND
> -	* KEY_VOLUMEUP
> -	* KEY_VOLUMEDOWN
> -	*/
> -	if (ctx->ts3a227e_present)
> -		jack_type = SND_JACK_HEADPHONE | SND_JACK_MICROPHONE |
> -					SND_JACK_BTN_0 | SND_JACK_BTN_1 |
> -					SND_JACK_BTN_2 | SND_JACK_BTN_3;
> -	else
> -		jack_type = SND_JACK_HEADPHONE | SND_JACK_MICROPHONE;
> -
> -	ret = snd_soc_card_jack_new(runtime->card, "Headset Jack",
> -					jack_type, jack, NULL, 0);
> -
> -	if (ret) {
> -		dev_err(runtime->dev, "Headset Jack creation failed %d\n", ret);
> -		return ret;
> -	}
>   
>   	if (ctx->ts3a227e_present)
> -		snd_soc_jack_notifier_register(jack, &cht_jack_nb);
> +		snd_soc_jack_notifier_register(&ctx->jack, &cht_jack_nb);
>   
> -	return ret;
> +	return 0;
>   }
>   
>   static int cht_codec_fixup(struct snd_soc_pcm_runtime *rtd,
> @@ -188,8 +163,32 @@ static int cht_max98090_headset_init(struct snd_soc_component *component)
>   {
>   	struct snd_soc_card *card = component->card;
>   	struct cht_mc_private *ctx = snd_soc_card_get_drvdata(card);
> +	struct snd_soc_jack *jack = &ctx->jack;
> +	int jack_type;
> +	int ret;
> +
> +	/*
> +	 * TI supports 4 butons headset detection
> +	 * KEY_MEDIA
> +	 * KEY_VOICECOMMAND
> +	 * KEY_VOLUMEUP
> +	 * KEY_VOLUMEDOWN
> +	 */
> +	if (ctx->ts3a227e_present)
> +		jack_type = SND_JACK_HEADPHONE | SND_JACK_MICROPHONE |
> +					SND_JACK_BTN_0 | SND_JACK_BTN_1 |
> +					SND_JACK_BTN_2 | SND_JACK_BTN_3;
> +	else
> +		jack_type = SND_JACK_HEADPHONE | SND_JACK_MICROPHONE;
> +
> +	ret = snd_soc_card_jack_new(card, "Headset Jack", jack_type, jack,
> +				    NULL, 0);
> +	if (ret) {
> +		dev_err(card->dev, "Headset Jack creation failed %d\n", ret);
> +		return ret;
> +	}
>   
> -	return ts3a227e_enable_jack_detect(component, &ctx->jack);
> +	return ts3a227e_enable_jack_detect(component, jack);
>   }
>   
>   static const struct snd_soc_ops cht_aif1_ops = {
>