From 078d3221ab066d7ab4565eb0b3bb199cebd2d838 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Sat, 12 Nov 2022 15:12:23 +0100 Subject: [PATCH] ALSA: usb-audio: Drop snd_BUG_ON() from snd_usbmidi_output_open() 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: 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 --- 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 bbff0923d2646..2839f6b6f09b4 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; -- 2.39.5