From mboxrd@z Thu Jan  1 00:00:00 1970
From: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Subject: Re: ALSA: firewire-lib: schedule work again when MIDI
 substream has rest of MIDI messages
Date: Thu, 15 Oct 2015 17:18:12 +0900
Message-ID: <561F6144.6070608@sakamocchi.jp>
References: <20151015070418.GA7076@mwanda>
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To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: alsa-devel@alsa-project.org
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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