Re: [PATCH 2/3] kvm: x86/mmu: Ensure TDP MMU roots are freed after yield

From: Maciej S. Szmigiero
Date: Wed Jan 06 2021 - 13:02:57 EST


On 06.01.2021 18:56, Ben Gardon wrote:
On Wed, Jan 6, 2021 at 9:37 AM Maciej S. Szmigiero
<maciej.szmigiero@xxxxxxxxxx> wrote:

On 06.01.2021 18:28, Ben Gardon wrote:
On Wed, Jan 6, 2021 at 1:26 AM Maciej S. Szmigiero
<maciej.szmigiero@xxxxxxxxxx> wrote:

Thanks for looking at it Ben.

On 06.01.2021 00:38, Ben Gardon wrote:
(..)

+Sean Christopherson, for whom I used a stale email address.
.
I tested this series by running kvm-unit-tests on an Intel Skylake
machine. It did not introduce any new failures. I also ran the
set_memory_region_test

It's "memslot_move_test" that is crashing the kernel - a memslot
move test based on "set_memory_region_test".

I apologize if I'm being very dense, but I can't find this test
anywhere.

No problem, the reproducer is available here:
https://urldefense.com/v3/__https://gist.github.com/maciejsszmigiero/890218151c242d99f63ea0825334c6c0__;!!GqivPVa7Brio!N4KXBbUfHtzFMD33RIWVJQmeTtSrFm4n-Ve84kFEkuewBJNuaOpsdmdoqTGnw8DT_EktHA$
as I stated in my original report.

Ah, that makes sense now. I didn't realize there were more files below
the .config. I added your test and can now reproduce the issue!

That's great!
Thanks for looking at it once again.

Maciej