Re: [PATCH v6 0/7] KVM: arm64: nv: Implement nested stage-2 reverse map

[Marc Zyngier]

On Wed, 16 Sep 2026 05:58:03 +0100,
Itaru Kitayama <itaru.kitayama@xxxxxxxxxxx> wrote:
> 
> Hi Wei-Lin,
> 
> On Tue, Sep 15, 2026 at 04:42:58PM +0100, Wei-Lin Chang wrote:
> > Hi,
> > 
> > This is v6 of optimizing the shadow s2 mmu unmapping during MMU
> > notifiers.
> > 
> > This version fixes a few issues, and adds Marc's space optimization
> > for kvm_guest_s2_mapping [1]. Please see the changelog for the details.
> > 
> > Tested by booting L3, and running in-kernel targetted tests described
> > in [2]. v5 got some tested-by's from Itaru and Wang (thanks), I didn't
> > carry them over since some bugs fixed in v6 are non-obvious. Some
> > retest would be much appreciated!
> > 
> > Series based on v7.3-rc3 + Marc's nested mmu lifecycle fixes [3].
> 
> Observed on QEMU (accel tcg) only, but I saw:
> 
> [ 1812.052752] BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1630
> [ 1812.052896] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 596, name: shadow_stage2
> 
> The kernel is built on top of Marc's fix and your version six series, but
> the fix for debugfs will be posted later?
> 
> Your hello_nested and shadow_stage2 ran without an issue.
> 
> Tested-by: Itaru Kitayama <itaru.kitayama@xxxxxxxxxxx>

So you have established that there is a critical locking bug, make
sure you don't communicate any information to help narrow where that
bug is, and yet give your Tested-by: tag?

What is the point? I'm baffled.

Can you at least provide an indication of what you did to get there as
well as the full backtrace?

	M.

-- 
Without deviation from the norm, progress is not possible.