Re: [PATCH rcu 10/11] srcu: Add FORCE_NEED_SRCU_NMI_SAFE Kconfig for testing

[Boqun Feng]

On Tue, Mar 25, 2025 at 08:51:05AM -0700, Paul E. McKenney wrote:
> On Tue, Mar 25, 2025 at 04:36:23PM +0100, Geert Uytterhoeven wrote:
> > Hi Paul,
> > 
> > On Tue, 25 Mar 2025 at 16:08, Paul E. McKenney <paulmck@xxxxxxxxxx> wrote:
> > > commit 2245ef8605a80726548253d885b4cadd97f69f3b
> > > Author: Paul E. McKenney <paulmck@xxxxxxxxxx>
> > > Date:   Tue Mar 25 07:31:45 2025 -0700
> > >
> > >     srcu: Make FORCE_NEED_SRCU_NMI_SAFE depend on RCU_EXPERT
> > >
> > >     The FORCE_NEED_SRCU_NMI_SAFE is useful only for those wishing to test
> > >     the SRCU code paths that accommodate architectures that do not have
> > >     NMI-safe per-CPU operations, that is, those architectures that do not
> > >     select the ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option.  As such, this
> > >     is a specialized Kconfig option that is not intended for casual users.
> > >
> > >     This commit therefore hides it behind the RCU_EXPERT Kconfig option.
> > >     Given that this new FORCE_NEED_SRCU_NMI_SAFE Kconfig option has no effect
> > >     unless the ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option is also selected,
> > >     it also depends on this Kconfig option.
> > >
> > >     [ paulmck: Apply Geert Uytterhoeven feedback. ]
> > >
> > >     Reported-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> > >     Closes: https://lore.kernel.org/all/CAMuHMdX6dy9_tmpLkpcnGzxyRbe6qSWYukcPp=H1GzZdyd3qBQ@xxxxxxxxxxxxxx/
> > >     Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
> > >
> > > diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig
> > > index b3f985d41717a..ceaf6594f634c 100644
> > > --- a/kernel/rcu/Kconfig
> > > +++ b/kernel/rcu/Kconfig
> > > @@ -68,6 +68,8 @@ config TREE_SRCU
> > >  config FORCE_NEED_SRCU_NMI_SAFE
> > >         bool "Force selection of NEED_SRCU_NMI_SAFE"
> > >         depends on !TINY_SRCU
> > > +       depends on RCU_EXPERT
> > > +       depends on ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
> > >         select NEED_SRCU_NMI_SAFE
> > >         default n
> > >         help
> > 
> > LGTM, so
> > Reviewed-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> 
> Applied, and thank you very much for both the review and the report!
> 

Queued for further testing, thank you both!

Regards,
Boqun

> 							Thanx, Paul