Re: [PATCH v5 3/4] KVM: s390: Change the fi->lock to a raw_spinlock for RT case

[Peter Zijlstra]

On Thu, May 07, 2026 at 04:45:49PM +0200, Heiko Carstens wrote:

> So... after having given this a second thought: we do not have
> PROVE_RAW_LOCK_NESTING enabled in our debug_defconfig (either we missed it,
> or somebody (cough) thought it is not relevant for s390). That said, I
> believe we should enable it, fix all fallout and also make sure that new
> code does not generate any lockdep splats with PROVE_RAW_LOCK_NESTING
> enabled.
> 
> Rationale: even though it is not relevant for s390, we also change common
> code; and by ignoring PROVE_RAW_LOCK_NESTING we might cause problems for
> other architectures by introducing incorrect nesting of locks in common
> code. So yes, your thinking is correct.
> 
> Peter, I just added you to cc, so you can correct me if I'm entirely wrong.

Makes sense to me; thanks for doing so!