[alsa-devel] bug report: aloop: potential signedness bug in loopback_prepare()

[Jaroslav Kysela]

On Sat, 9 Oct 2010, Dan Carpenter wrote:

> Hi Jaroslav,
>
> sound/drivers/aloop.c +287 loopback_prepare(10)
> 	warn: bogus compare against zero: 'bps'
>   282          unsigned int bps, salign;
>   283
>   284          salign = (snd_pcm_format_width(runtime->format) *
>   285							runtime->channels) / 8;
>   286          bps = salign * runtime->rate;
>   287          if (bps <= 0 || salign <= 0)
>                    ^^^^^^^^^^^^^^^^^^^^^^^
>
>
> 	Both "bps" and "salign" are unsigned and are never less than
> 	zero.  Should this just be checking for == 0?  Or was the check
> 	supposed to catch integer overflows?

The condition works for both signed and unsigned values. That was only 
reason why I did not write '==' there.

 					Jaroslav

-----
Jaroslav Kysela <perex at perex.cz>
Linux Kernel Sound Maintainer
ALSA Project, Red Hat, Inc.