[alsa-devel] bug report: aloop: potential signedness bug in loopback_prepare()
error27 at gmail.com
Sat Oct 9 16:58:46 CEST 2010
On Sat, Oct 09, 2010 at 02:14:30PM +0200, Jaroslav Kysela wrote:
> 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;
>> 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.
What I mean is that the less than zero part is never true. For example,
the following test program will print "more" instead of "less".
int main(int argc, char **argv)
unsigned int x = -3;
if (x <= 0)
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