KVM: VMX: fix use after free of vmx->loaded_vmcs

After free_loaded_vmcs executes, the "loaded_vmcs" structure
is kfreed, and now vmx->loaded_vmcs points to a kfreed area.
Subsequent free_loaded_vmcs then attempts to manipulate
vmx->loaded_vmcs.

Switch the order to avoid the problem.

https://bugzilla.redhat.com/show_bug.cgi?id=1047892

Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 0abf8b783f19..7661eb171936 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -7390,8 +7390,8 @@ static void vmx_free_vcpu(struct kvm_vcpu *vcpu)
         struct vcpu_vmx *vmx = to_vmx(vcpu);
 
         free_vpid(vmx);
-        free_nested(vmx);
         free_loaded_vmcs(vmx->loaded_vmcs);
+        free_nested(vmx);
         kfree(vmx->guest_msrs);
         kvm_vcpu_uninit(vcpu);
         kmem_cache_free(kvm_vcpu_cache, vmx);