[alsa-devel] [PATCH 2/5] ASoC: dwc: Don't allow negative use counts

[Mark Brown]

On Thu, Dec 04, 2014 at 09:00:35AM +0000, Andrew Jackson wrote:
> On 12/03/14 17:25, Mark Brown wrote:
> > On Wed, Dec 03, 2014 at 04:38:55PM +0000, Andrew Jackson wrote:

> >>  	case SNDRV_PCM_TRIGGER_STOP:
> >>  	case SNDRV_PCM_TRIGGER_SUSPEND:
> >>  	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
> >> -		dev->active--;
> >> +		if (dev->active > 0)
> >> +			dev->active--;

> > How is this triggering - this sounds like you're papering over some
> > other bug somewhere?

> When I looked at the code paths I couldn't convince myself that STOP
> wouldn't be called more than once.  Then actuve would be negative and
> the device might not be restartable.  I didn't have a problem per se,
> it was just that it seemed to be something of a loophole.

If you're just adding the check on the off chance that it might fire you
need to add a warning message as well - what your change does is make
the code look like it's supposed to have broken reference counting since
it has a check to silently fix up and ignore problems.
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