Commit b5d1f31d authored Aug 15, 2019 by Takashi Iwai Committed by Greg Kroah-Hartman Sep 06, 2019

ALSA: usb-audio: Fix invalid NULL check in snd_emuusb_set_samplerate()



commit 6de3c9e3f6b3eaf66859e1379b3f35dda781416b upstream.

The quirk function snd_emuusb_set_samplerate() has a NULL check for
the mixer element, but this is useless in the current code.  It used
to be a check against mixer->id_elems[unitid] but it was changed later
to the value after mixer_eleme_list_to_info() which is always non-NULL
due to the container_of() usage.

This patch fixes the check before the conversion.

While we're at it, correct a typo in the comment in the function,
too.

Fixes: 8c558076 ("ALSA: usb-audio: Clean up mixer element list traverse")
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 98a2017c

sound/usb/mixer_quirks.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -1167,19 +1167,19 @@ void snd_emuusb_set_samplerate(struct snd_usb_audio *chip,
		{
		struct usb_mixer_interface *mixer;
		struct usb_mixer_elem_info *cval;
		int unitid = 12; /* SamleRate ExtensionUnit ID */
		int unitid = 12; /* SampleRate ExtensionUnit ID */

		list_for_each_entry(mixer, &chip->mixer_list, list) {
		if (mixer->id_elems[unitid]) {
		cval = mixer_elem_list_to_info(mixer->id_elems[unitid]);
		if (cval) {
		snd_usb_mixer_set_ctl_value(cval, UAC_SET_CUR,
		cval->control << 8,
		samplerate_id);
		snd_usb_mixer_notify_id(mixer, unitid);
		}
		break;
		}
		}
		}

		/* M-Audio Fast Track C400/C600 */
		/* C400/C600 volume controls, this control needs a volume quirk, see mixer.c */