Merge tag 'sound-4.15-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound

Pull sound fixes from Takashi Iwai:
 "All fixes are small and for stable:

   - a PCM ioctl race fix

   - yet another USB-audio hardening for malicious descriptors

   - Realtek ALC257 codec support"

* tag 'sound-4.15-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: pcm: prevent UAF in snd_pcm_info
  ALSA: hda/realtek - New codec support for ALC257
  ALSA: usb-audio: Add check return value for usb_string()
  ALSA: usb-audio: Fix out-of-bound error
  ALSA: seq: Remove spurious WARN_ON() at timer check

sound/core/pcm.c

@@ -153,7 +153,9 @@ static int snd_pcm_control_ioctl(struct snd_card *card,
 				err = -ENXIO;
 				goto _error;
 			}
+			mutex_lock(&pcm->open_mutex);
 			err = snd_pcm_info_user(substream, info);
+			mutex_unlock(&pcm->open_mutex);
 		_error:
 			mutex_unlock(&register_mutex);
 			return err;

sound/core/seq/seq_timer.c

@@ -355,7 +355,7 @@ static int initialize_timer(struct snd_seq_timer *tmr)
 	unsigned long freq;
 
 	t = tmr->timeri->timer;
-	if (snd_BUG_ON(!t))
+	if (!t)
 		return -EINVAL;
 
 	freq = tmr->preferred_resolution;

sound/pci/hda/patch_realtek.c

@@ -330,6 +330,7 @@ static void alc_fill_eapd_coef(struct hda_codec *codec)
 	case 0x10ec0236:
 	case 0x10ec0255:
 	case 0x10ec0256:
+	case 0x10ec0257:
 	case 0x10ec0282:
 	case 0x10ec0283:
 	case 0x10ec0286:
@@ -2772,6 +2773,7 @@ enum {
 	ALC269_TYPE_ALC298,
 	ALC269_TYPE_ALC255,
 	ALC269_TYPE_ALC256,
+	ALC269_TYPE_ALC257,
 	ALC269_TYPE_ALC215,
 	ALC269_TYPE_ALC225,
 	ALC269_TYPE_ALC294,
@@ -2805,6 +2807,7 @@ static int alc269_parse_auto_config(struct hda_codec *codec)
 	case ALC269_TYPE_ALC298:
 	case ALC269_TYPE_ALC255:
 	case ALC269_TYPE_ALC256:
+	case ALC269_TYPE_ALC257:
 	case ALC269_TYPE_ALC215:
 	case ALC269_TYPE_ALC225:
 	case ALC269_TYPE_ALC294:
@@ -6867,6 +6870,10 @@ static int patch_alc269(struct hda_codec *codec)
 		spec->gen.mixer_nid = 0; /* ALC256 does not have any loopback mixer path */
 		alc_update_coef_idx(codec, 0x36, 1 << 13, 1 << 5); /* Switch pcbeep path to Line in path*/
 		break;
+	case 0x10ec0257:
+		spec->codec_variant = ALC269_TYPE_ALC257;
+		spec->gen.mixer_nid = 0;
+		break;
 	case 0x10ec0215:
 	case 0x10ec0285:
 	case 0x10ec0289:
@@ -7914,6 +7921,7 @@ static const struct hda_device_id snd_hda_id_realtek[] = {
 	HDA_CODEC_ENTRY(0x10ec0236, "ALC236", patch_alc269),
 	HDA_CODEC_ENTRY(0x10ec0255, "ALC255", patch_alc269),
 	HDA_CODEC_ENTRY(0x10ec0256, "ALC256", patch_alc269),
+	HDA_CODEC_ENTRY(0x10ec0257, "ALC257", patch_alc269),
 	HDA_CODEC_ENTRY(0x10ec0260, "ALC260", patch_alc260),
 	HDA_CODEC_ENTRY(0x10ec0262, "ALC262", patch_alc262),
 	HDA_CODEC_ENTRY(0x10ec0267, "ALC267", patch_alc268),

sound/usb/mixer.c

@@ -204,6 +204,10 @@ static int snd_usb_copy_string_desc(struct mixer_build *state,
 				    int index, char *buf, int maxlen)
 {
 	int len = usb_string(state->chip->dev, index, buf, maxlen - 1);
+
+	if (len < 0)
+		return 0;
+
 	buf[len] = 0;
 	return len;
 }
@@ -2174,12 +2178,13 @@ static int parse_audio_selector_unit(struct mixer_build *state, int unitid,
 	if (len)
 		;
 	else if (nameid)
-		snd_usb_copy_string_desc(state, nameid, kctl->id.name,
+		len = snd_usb_copy_string_desc(state, nameid, kctl->id.name,
 					 sizeof(kctl->id.name));
-	else {
+	else
 		len = get_term_name(state, &state->oterm,
 				    kctl->id.name, sizeof(kctl->id.name), 0);
-		if (!len)
+
+	if (!len) {
 		strlcpy(kctl->id.name, "USB", sizeof(kctl->id.name));
 
 		if (desc->bDescriptorSubtype == UAC2_CLOCK_SELECTOR)