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