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From:   Jack Wang <jack.wang.usish@gmail.com>
Date:   Mon, 29 Jul 2019 10:58:30 +0200
Message-ID: <CA+res+RfqpT=g1QbCqr3OkHVzFFSAt3cfCYNcwqiemWmOifFxg@mail.gmail.com>
Subject: Re: [PATCH stable-4.19 1/2] KVM: nVMX: do not use dangling shadow
 VMCS after guest reset
To:     Vitaly Kuznetsov <vkuznets@redhat.com>
Cc:     stable@vger.kernel.org, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
        =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= <rkrcmar@redhat.com>
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Vitaly Kuznetsov <vkuznets@redhat.com> =E4=BA=8E2019=E5=B9=B47=E6=9C=8825=
=E6=97=A5=E5=91=A8=E5=9B=9B =E4=B8=8B=E5=8D=883:29=E5=86=99=E9=81=93=EF=BC=
=9A
>
> From: Paolo Bonzini <pbonzini@redhat.com>
>
> [ Upstream commit 88dddc11a8d6b09201b4db9d255b3394d9bc9e57 ]
>
> If a KVM guest is reset while running a nested guest, free_nested will
> disable the shadow VMCS execution control in the vmcs01.  However,
> on the next KVM_RUN vmx_vcpu_run would nevertheless try to sync
> the VMCS12 to the shadow VMCS which has since been freed.
>
> This causes a vmptrld of a NULL pointer on my machime, but Jan reports
> the host to hang altogether.  Let's see how much this trivial patch fixes=
.
>
> Reported-by: Jan Kiszka <jan.kiszka@siemens.com>
> Cc: Liran Alon <liran.alon@oracle.com>
> Cc: stable@vger.kernel.org
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Hi all,

Do we need to backport the fix also to stable 4.14?  It applies
cleanly and compiles fine.

Regards,
Jack Wang