From ad72c3c3f6eb81d2cb189ec71e888316adada5df Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Sat, 12 Nov 2022 15:12:23 +0100
Subject: [PATCH] ALSA: usb-audio: Drop snd_BUG_ON() from snd_usbmidi_output_open()
Git-commit: ad72c3c3f6eb81d2cb189ec71e888316adada5df
Patch-mainline: v6.1-rc6
References: git-fixes

snd_usbmidi_output_open() has a check of the NULL port with
snd_BUG_ON().  snd_BUG_ON() was used as this shouldn't have happened,
but in reality, the NULL port may be seen when the device gives an
invalid endpoint setup at the descriptor, hence the driver skips the
allocation.  That is, the check itself is valid and snd_BUG_ON()
should be dropped from there.  Otherwise it's confusing as if it were
a real bug, as recently syzbot stumbled on it.

Reported-by: syzbot+9abda841d636d86c41da@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/syzbot+9abda841d636d86c41da@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/20221112141223.6144-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

---
 sound/usb/midi.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/sound/usb/midi.c b/sound/usb/midi.c
index bbff0923d264..2839f6b6f09b 100644
--- a/sound/usb/midi.c
+++ b/sound/usb/midi.c
@@ -1133,10 +1133,8 @@ static int snd_usbmidi_output_open(struct snd_rawmidi_substream *substream)
 					port = &umidi->endpoints[i].out->ports[j];
 					break;
 				}
-	if (!port) {
-		snd_BUG();
+	if (!port)
 		return -ENXIO;
-	}
 
 	substream->runtime->private_data = port;
 	port->state = STATE_UNKNOWN;
-- 
2.35.3