Hi,

On Oct 15 2015 16:04, Dan Carpenter wrote:

Hello Takashi Sakamoto,

This is a semi-automatic email about new static checker warnings.

The patch e8a40d9bcb23: "ALSA: firewire-lib: schedule work again when MIDI substream has rest of MIDI messages" from Oct 9, 2015, leads to the following Smatch complaint:

sound/firewire/lib.c:88 async_midi_port_callback() error: we previously assumed 'substream' could be null (see line 77)

sound/firewire/lib.c 76 77 if (rcode == RCODE_COMPLETE && substream != NULL) ^^^^^^^^^^^^^^^^^ Existing code assumes substream can be NULL.

 78			snd_rawmidi_transmit_ack(substream, port->consume_bytes);
 79		else if (!rcode_is_permanent_error(rcode))
 80			/* To start next transaction immediately for recovery. */
 81			port->next_ktime = ktime_set(0, 0);
 82		else
 83			/* Don't continue processing. */
 84			port->error = true;
 85	
 86		port->idling = true;
 87	
 88		if (!snd_rawmidi_transmit_empty(substream))
                                             ^^^^^^^^^

Patch adds an unchecked dereference (inside the function call).

 89			schedule_work(&port->work);
 90	}

regards, dan carpenter

Indeed. I'll fix this bug in this weekend.

Thanks

Takashi Sakamoto