[alsa-devel] [PATCH] ALSA: hda - hdmi get jack from hda_jack_tbl when not dyn_pcm_assign

[Takashi Iwai]

On Thu, 18 Feb 2016 06:25:02 +0100,
libin.yang at linux.intel.com wrote:
> 
> From: Libin Yang <libin.yang at linux.intel.com>
> 
> On Intel platform, if !dyn_pcm_assign, spec->pcm_rec[].jack is not
> NULL even after snd_hda_jack_tbl_clear() is called to free snd_jack.
> This may cause access invalid memory when calling snd_jack_report.
> 
> Please see more detail from:
> https://bugs.freedesktop.org/show_bug.cgi?id=94079
> 
> Signed-off-by: Libin Yang <libin.yang at linux.intel.com>
> ---
>  sound/pci/hda/patch_hdmi.c | 16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
> index f4443b5..3b47101 100644
> --- a/sound/pci/hda/patch_hdmi.c
> +++ b/sound/pci/hda/patch_hdmi.c
> @@ -1962,6 +1962,7 @@ static void sync_eld_via_acomp(struct hda_codec *codec,
>  {
>  	struct hdmi_spec *spec = codec->spec;
>  	struct hdmi_eld *eld = &spec->temp_eld;
> +	struct hda_jack_tbl *jack_tbl;
>  	struct snd_jack *jack = NULL;
>  	int size;
>  
> @@ -1989,10 +1990,21 @@ static void sync_eld_via_acomp(struct hda_codec *codec,
>  	/* pcm_idx >=0 before update_eld() means it is in monitor
>  	 * disconnected event. Jack must be fetched before update_eld()
>  	 */
> -	if (per_pin->pcm_idx >= 0)
> +	/* if !dyn_pcm_assign, get jack from hda_jack_tbl
> +	 * in !dyn_pcm_assign case, spec->pcm_rec[].jack is not
> +	 * NULL even after snd_hda_jack_tbl_clear() is called to
> +	 * free snd_jack. This may cause access invalid memory
> +	 * when calling snd_jack_report
> +	 */
> +	if (per_pin->pcm_idx >= 0 && spec->dyn_pcm_assign)
>  		jack = spec->pcm_rec[per_pin->pcm_idx].jack;
> +	else {
> +		jack_tbl = snd_hda_jack_tbl_get(codec, per_pin->pin_nid);
> +		if (jack_tbl)
> +			jack = jack_tbl->jack;
> +	}
>  	update_eld(codec, per_pin, eld);
> -	if (jack == NULL && per_pin->pcm_idx >= 0)
> +	if (jack == NULL && per_pin->pcm_idx >= 0 && spec->dyn_pcm_assign)
>  		jack = spec->pcm_rec[per_pin->pcm_idx].jack;
>  	if (jack == NULL)
>  		goto unlock;

I'd create a separate small helper function, e.g. pin_to_jack()
doing like:

pin_idx_to_jack(codec, per_pin)
{
	if (spec->dyn_pcm_assign) {
		if (per_pin->pcm_idx < 0)
			return NULL;
		return spec->pcm_rec[per_pin->pcm_idx].jack;
	} else {
		jack_tbl = snd_hda_jack_tbl_get(codec, per_pin->pin_nid);
		if (!jack_tbl)
			return NULL;
		return jack_tbl->jack;
	}
}

Then the code update_eld() will be cleaner,

	jack = pin_to_jack(codec, per_pin);
	update_eld(codec, per_pin, eld);
	if (!jack)
		jack = pin_to_jack(codec, per_pin);
	if (!jack)
		goto unlock;

Alternatively, assign pcm_rec[].jack beforehand for non-dyn PCM.
It's fixed, so you can assign it in initialization.


thanks,

Takashi