When asynchronous MIDI port is closed before callbacked, the callback function causes NULL pointer dereference to missing MIDI substream.
This commit fixes this bug.
Fixes: e8a40d9bcb23('ALSA: firewire-lib: schedule work again when MIDI substream has rest of MIDI messages') Reported-by: Dan Carpenter dan.carpenter@oracle.com Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp --- sound/firewire/lib.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/sound/firewire/lib.c b/sound/firewire/lib.c index edf1c8b..f80aafa 100644 --- a/sound/firewire/lib.c +++ b/sound/firewire/lib.c @@ -74,7 +74,11 @@ static void async_midi_port_callback(struct fw_card *card, int rcode, struct snd_fw_async_midi_port *port = callback_data; struct snd_rawmidi_substream *substream = ACCESS_ONCE(port->substream);
- if (rcode == RCODE_COMPLETE && substream != NULL) + /* This port is closed. */ + if (substream == NULL) + return; + + if (rcode == RCODE_COMPLETE) snd_rawmidi_transmit_ack(substream, port->consume_bytes); else if (!rcode_is_permanent_error(rcode)) /* To start next transaction immediately for recovery. */