Re: [DMARC error][SPF error] Re: [PATCH v4 00/10] devm_led_classdev_register() usage problem

[George Stark]

Hello Andy.


I haven't lose hope for the devm_mutex thing and keep pinging those guys 
from time to time.

Sure I can single out the fix-only patch I'll do it tomorrow.


On 2/9/24 20:11, Andy Shevchenko wrote:
> On Thu, Dec 21, 2023 at 03:11:11PM +0000, Lee Jones wrote:
> > On Thu, 14 Dec 2023, George Stark wrote:
> >
> > > This patch series fixes the problem of devm_led_classdev_register misusing.
> > >
> > > The basic problem is described in [1]. Shortly when devm_led_classdev_register()
> > > is used then led_classdev_unregister() called after driver's remove() callback.
> > > led_classdev_unregister() calls driver's brightness_set callback and that callback
> > > may use resources which were destroyed already in driver's remove().
> > >
> > > After discussion with maintainers [2] [3] we decided:
> > > 1) don't touch led subsytem core code and don't remove led_set_brightness() from it
> > > but fix drivers
> > > 2) don't use devm_led_classdev_unregister
> > >
> > > So the solution is to use devm wrappers for all resources
> > > driver's brightness_set() depends on. And introduce dedicated devm wrapper
> > > for mutex as it's often used resource.
> > >
> > > [1] https://lore.kernel.org/lkml/8704539b-ed3b-44e6-aa82-586e2f895e2b@xxxxxxxxxxxxxxxxx/T/
> > > [2] https://lore.kernel.org/lkml/8704539b-ed3b-44e6-aa82-586e2f895e2b@xxxxxxxxxxxxxxxxx/T/#mc132b9b350fa51931b4fcfe14705d9f06e91421f
> > > [3] https://lore.kernel.org/lkml/8704539b-ed3b-44e6-aa82-586e2f895e2b@xxxxxxxxxxxxxxxxx/T/#mdbf572a85c33f869a553caf986b6228bb65c8383
>
> ...
>
> > FYI: I'll conduct my review once the locking side is settled.
>
> To reduce burden can you apply the first one? It's a fix.

--
Best regards
George