]> git.ipfire.org Git - thirdparty/kernel/stable.git/commitdiff
ALSA: usb-audio: Drop snd_BUG_ON() from snd_usbmidi_output_open()
authorTakashi Iwai <tiwai@suse.de>
Sat, 12 Nov 2022 14:12:23 +0000 (15:12 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 25 Nov 2022 16:35:40 +0000 (17:35 +0100)
commit ad72c3c3f6eb81d2cb189ec71e888316adada5df upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sound/usb/midi.c

index 83da676519a8deb9a2d55cf07443542ddbbfbaf4..53d16b168df8119054edaa1cb401d4b3fd6e6b0b 100644 (file)
@@ -1148,10 +1148,8 @@ 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;