Re: [PATCH v3 04/20] lockdep: Add preemption enabled/disabled assertion APIs

[Sebastian A. Siewior]

On 2020-07-06 22:50:04 [+0200], Peter Zijlstra wrote:
> On Tue, Jun 30, 2020 at 07:44:36AM +0200, Ahmed S. Darwish wrote:
> > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> > index d74ac0fd6b2d..e5e2e632b749 100644
> > --- a/lib/Kconfig.debug
> > +++ b/lib/Kconfig.debug
> > @@ -1118,6 +1118,7 @@ config PROVE_LOCKING
> >  	select DEBUG_RWSEMS
> >  	select DEBUG_WW_MUTEX_SLOWPATH
> >  	select DEBUG_LOCK_ALLOC
> > +	select PREEMPT_COUNT if !ARCH_NO_PREEMPT
> >  	select TRACE_IRQFLAGS
> >  	default n
> >  	help
> 
> I suspect this can be done unconditional, the thing that requires arch
> support is CONFIG_PREEMPTION.

|$ git grep -C 2 PREEMPT_COUNT lib/Kconfig.debug 
|lib/Kconfig.debug-config DEBUG_ATOMIC_SLEEP
|lib/Kconfig.debug-      bool "Sleep inside atomic section checking"
|lib/Kconfig.debug:      select PREEMPT_COUNT
|lib/Kconfig.debug-      depends on DEBUG_KERNEL
|lib/Kconfig.debug-      depends on !ARCH_NO_PREEMPT

There will be a build fault if you force preempt_count.

Sebastian