[alsa-devel] [PATCH] sound: hdmi: avoid dereferencing uninitialized 'jack' pointer

[Takashi Iwai]

On Wed, 24 Feb 2016 17:18:58 +0100,
Arnd Bergmann wrote:
> 
> On Wednesday 17 February 2016 10:35:40 Takashi Iwai wrote:
> > On Wed, 17 Feb 2016 10:03:50 +0100,
> > +	const char *id;
> > +#ifdef CONFIG_SND_JACK_INPUT_DEV
> > +	struct input_dev *input_dev;
> >  	int registered;
> >  	int type;
> > -	const char *id;
> >  	char name[100];
> >  	unsigned int key[6];   /* Keep in sync with definitions above */
> > +#endif /* CONFIG_SND_JACK_INPUT_DEV */
> >  	void *private_data;
> >  	void (*private_free)(struct snd_jack *);
> >  };
> 
> I got a build error from this today, as the trace event tries to print
> the jack "name" field. I've managed to get it to build again by printing
> the "id" field in place of the "name". The name is normally assigned
> from id in snd_jack_dev_register using
> 
>         snprintf(jack->name, sizeof(jack->name), "%s %s",
>                  card->shortname, jack->id);
> 
> but that code is not called here at all. My patch will slightly
> alter the output as a consequence, but I don't know if this change
> is critical or not.

Thanks for catching this.  Yes, your fix is correct.  This must have
been a wrong pick up when converting from the standalone hda jack to
unified jack stuff.

Could you send a proper patch for inclusion?


Takashi

> 
> 	Arnd
> 
> diff --git a/include/trace/events/asoc.h b/include/trace/events/asoc.h
> index 317a1ed2f4ac..9130dd5a184a 100644
> --- a/include/trace/events/asoc.h
> +++ b/include/trace/events/asoc.h
> @@ -231,13 +231,13 @@ TRACE_EVENT(snd_soc_jack_report,
>  	TP_ARGS(jack, mask, val),
>  
>  	TP_STRUCT__entry(
> -		__string(	name,		jack->jack->name	)
> +		__string(	name,		jack->jack->id		)
>  		__field(	int,		mask			)
>  		__field(	int,		val			)
>  	),
>  
>  	TP_fast_assign(
> -		__assign_str(name, jack->jack->name);
> +		__assign_str(name, jack->jack->id);
>  		__entry->mask = mask;
>  		__entry->val = val;
>  	),
> @@ -253,12 +253,12 @@ TRACE_EVENT(snd_soc_jack_notify,
>  	TP_ARGS(jack, val),
>  
>  	TP_STRUCT__entry(
> -		__string(	name,		jack->jack->name	)
> +		__string(	name,		jack->jack->id		)
>  		__field(	int,		val			)
>  	),
>  
>  	TP_fast_assign(
> -		__assign_str(name, jack->jack->name);
> +		__assign_str(name, jack->jack->id);
>  		__entry->val = val;
>  	),
>  
>