diff --git a/virt/kvm/assigned-dev.c b/virt/kvm/assigned-dev.c
index bf06577..5819a27 100644
--- a/virt/kvm/assigned-dev.c
+++ b/virt/kvm/assigned-dev.c
@@ -526,8 +526,10 @@
 		dev->irq_requested_type |= guest_irq_type;
 		if (dev->ack_notifier.gsi != -1)
 			kvm_register_irq_ack_notifier(kvm, &dev->ack_notifier);
-	} else
+	} else {
 		kvm_free_irq_source_id(kvm, dev->irq_source_id);
+		dev->irq_source_id = -1;
+	}
 
 	return r;
 }