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

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Date:   Wed, 6 Jan 2021 19:02:05 +0100
From:   "Maciej S. Szmigiero" <maciej.szmigiero@...cle.com>
To:     Ben Gardon <bgardon@...gle.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Peter Shier <pshier@...gle.com>,
        Leo Hou <leohou1402@...il.com>,
        LKML <linux-kernel@...r.kernel.org>, kvm <kvm@...r.kernel.org>,
        Sean Christopherson <seanjc@...gle.com>
Subject: Re: [PATCH 2/3] kvm: x86/mmu: Ensure TDP MMU roots are freed after
 yield

On 06.01.2021 18:56, Ben Gardon wrote:
> On Wed, Jan 6, 2021 at 9:37 AM Maciej S. Szmigiero
> <maciej.szmigiero@...cle.com> wrote:
>>
>> On 06.01.2021 18:28, Ben Gardon wrote:
>>> On Wed, Jan 6, 2021 at 1:26 AM Maciej S. Szmigiero
>>> <maciej.szmigiero@...cle.com> 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