Re: [PATCH] Input: pwm-beeper - fix: scheduling while atomic

From: Dmitry Torokhov
Date: Wed May 25 2016 - 20:36:25 EST


On Tue, May 24, 2016 at 10:32:53AM +0200, Manfred Schlaegl wrote:
> On 2016-05-20 18:59, Dmitry Torokhov wrote:
> > Hi Manfred,
> >
> > On Wed, May 18, 2016 at 05:16:49PM +0200, Manfred Schlaegl wrote:
> >> @@ -133,6 +149,8 @@ static int pwm_beeper_remove(struct platform_device *pdev)
> >> {
> >> struct pwm_beeper *beeper = platform_get_drvdata(pdev);
> >>
> >> + cancel_work_sync(&beeper->work);
> >> +
> >> input_unregister_device(beeper->input);
> >
> > This is racy, request to play may come in after cancel_work_sync()
> > returns but before we unregistered input device. I think you want the
> > version below.
> >
>
> Hi Dmitry,
>
> yes you are right. Thank you for your feedback.
> I also see that point, but I think it would be a simpler change just
> to cancel the worker after unregistering the device (to reorder
> cancel_work_sync and input_unregister_device).

That is an option, but I wanter to have close() because I also want to
convert the driver to used devm for allocating resources, and then we'd
need close() anyway so that we can get rid of remove() method.

Thanks.

--
Dmitry