int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu, struct kvm_interrupt *irq)
{
	if (irq->irq == KVM_INTERRUPT_UNSET) {
		kvmppc_core_dequeue_external(vcpu);
		return 0;
	}

	kvmppc_core_queue_external(vcpu, irq);

	kvm_vcpu_kick(vcpu);

	return 0;
}

The product dereferences a pointer that it expects to be valid but is NULL.