linux-kernel - Re: [PATCH] KVM: x86: Forcibly leave nested virt when SMM state is toggled

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Message-ID: <8d3a11be-a7eb-5ad0-2ef6-abc9276ced2f@linaro.org>
Date:   Thu, 24 Feb 2022 10:59:53 -0800
From:   Tadeusz Struk <tadeusz.struk@...aro.org>
To:     Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>
Cc:     Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        syzbot+8112db3ab20e70d50c31@...kaller.appspotmail.com
Subject: Re: [PATCH] KVM: x86: Forcibly leave nested virt when SMM state is
 toggled

On 2/18/22 10:14, Paolo Bonzini wrote:
> On 2/18/22 18:22, Tadeusz Struk wrote:
>> On 2/18/22 08:58, Sean Christopherson wrote:
>>> This SMM-specific patch fixes something different, the bug that you are still
>>> hitting is the FNAME(cmpxchg_gpte) mess.  The uaccess CMPXCHG series[*] that
>>> properly fixes that issue hasn't been merged yet.
>>>
>>>    ==================================================================
>>>    BUG: KASAN: use-after-free in ept_cmpxchg_gpte.constprop.0+0x3c3/0x590
>>>    Write of size 8 at addr ffff888010000000 by task repro/5633
>>>
>>> [*]https://lore.kernel.org/all/20220202004945.2540433-1-seanjc@google.com
>>>
>>
>> Ok, that's good. I will keep an eye on it and give it a try then.
> 
> I'll poke PeterZ for a review next week.
> 

Paulo, do you know if PeterZ had a chance to look at the uaccess patches yet?

-- 
Thanks,
Tadeusz