Re: [bug report] ALSA: usb-audio: Tascam US-16x08 DSP mixer quirk

[Takashi Iwai <tiwai@suse.de>]

On Wed, 22 Feb 2017 19:46:49 +0100,
Dan Carpenter wrote:
> 
> Hello Detlef Urban,
> 
> This is a semi-automatic email about new static checker warnings.
> 
> The patch d2bb390a2081: "ALSA: usb-audio: Tascam US-16x08 DSP mixer 
> quirk" from Feb 20, 2017, leads to the following Smatch complaint:
> 
> sound/usb/mixer_us16x08.c:716 snd_us16x08_meter_get()
> 	 warn: variable dereferenced before check 'elem' (see line 711)
> 
> sound/usb/mixer_us16x08.c
>    710		struct usb_mixer_elem_info *elem = kcontrol->private_data;
>    711		struct snd_usb_audio *chip = elem->head.mixer->chip;
>                                              ^^^^^^^^^^^^^^^^^^^^^^
> Dereference.
> 
>    712		struct snd_us16x08_meter_store *store = elem->private_data;
>    713		u8 meter_urb[64];
>    714		char tmp[max(sizeof(mix_init_msg1), sizeof(mix_init_msg2))];
>    715	
>    716		if (elem) {
>                     ^^^^
> Check.
> 
>    717			store = (struct snd_us16x08_meter_store *) elem->private_data;
>    718			chip = elem->head.mixer->chip;

Thanks for the report.
The buggy part was already removed in the later patch.


Takashi