Re: [PATCH] powerpc/smp: Move rcu_cpu_starting() earlier

[Qian Cai]

On Wed, 2020-10-28 at 17:31 -0700, Paul E. McKenney wrote:
> On Thu, Oct 29, 2020 at 11:09:07AM +1100, Michael Ellerman wrote:
> > Qian Cai <cai@xxxxxxxxxx> writes:
> > > The call to rcu_cpu_starting() in start_secondary() is not early enough
> > > in the CPU-hotplug onlining process, which results in lockdep splats as
> > > follows:
> > 
> > Since when?
> > What kernel version?
> > 
> > I haven't seen this running CPU hotplug tests with PROVE_LOCKING=y on
> > v5.10-rc1. Am I missing a CONFIG?
> 
> My guess would be that adding CONFIG_PROVE_RAW_LOCK_NESTING=y will
> get you some splats.

Well, I don't have that set, so it should be CONFIG_PROVE_RCU_LIST=y. Anyway,
this is .config to reproduce on Power9 NV:

https://cailca.coding.net/public/linux/mm/git/files/master/powerpc.config