[patch] KVM: fix vcpu freeing bug

[patch] KVM: fix vcpu freeing bug

[Ingo Molnar]

From: Ingo Molnar <mingo-X9Un+BFzKDI@public.gmane.org>
Subject: [patch] KVM: fix vcpu freeing bug

vcpu_load() can return NULL and it sometimes does in failure paths (for 
example when the userspace ABI version is too old) - causing a 
preemption count underflow in the ->vcpu_free() later on. So check for 
NULL.

Signed-off-by: Ingo Molnar <mingo-X9Un+BFzKDI@public.gmane.org>

Index: linux/drivers/kvm/kvm_main.c
===================================================================
--- linux.orig/drivers/kvm/kvm_main.c
+++ linux/drivers/kvm/kvm_main.c
@@ -357,7 +357,9 @@ static void kvm_free_physmem(struct kvm 
 
 static void kvm_free_vcpu(struct kvm_vcpu *vcpu)
 {
-	vcpu_load(vcpu->kvm, vcpu_slot(vcpu));
+	if (!vcpu_load(vcpu->kvm, vcpu_slot(vcpu)))
+		return;
+
 	kvm_mmu_destroy(vcpu);
 	vcpu_put(vcpu);
 	kvm_arch_ops->vcpu_free(vcpu);

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Re: [patch] KVM: fix vcpu freeing bug

[Avi Kivity]

Ingo Molnar wrote:
> From: Ingo Molnar <mingo-X9Un+BFzKDI@public.gmane.org>
> Subject: [patch] KVM: fix vcpu freeing bug
>
> vcpu_load() can return NULL and it sometimes does in failure paths (for 
> example when the userspace ABI version is too old) - causing a 
> preemption count underflow in the ->vcpu_free() later on. So check for 
> NULL.
>
>   

Applied, thanks.


-- 
error compiling committee.c: too many arguments to function


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