diff --git a/pkg/registry/mock_registry.go b/pkg/registry/mock_registry.go
index 4b620354cdf..0d36ec0700a 100644
--- a/pkg/registry/mock_registry.go
+++ b/pkg/registry/mock_registry.go
@@ -27,7 +27,7 @@ type MockPodRegistry struct {
 	err  error
 	pod  *api.Pod
 	pods []api.Pod
-	sync.RWMutex
+	sync.Mutex
 }
 
 func MakeMockPodRegistry(pods []api.Pod) *MockPodRegistry {
@@ -37,8 +37,8 @@ func MakeMockPodRegistry(pods []api.Pod) *MockPodRegistry {
 }
 
 func (registry *MockPodRegistry) ListPods(selector labels.Selector) ([]api.Pod, error) {
-	registry.RLock()
-	defer registry.RUnlock()
+	registry.Lock()
+	defer registry.Unlock()
 	if registry.err != nil {
 		return registry.pods, registry.err
 	}
@@ -52,24 +52,24 @@ func (registry *MockPodRegistry) ListPods(selector labels.Selector) ([]api.Pod,
 }
 
 func (registry *MockPodRegistry) GetPod(podId string) (*api.Pod, error) {
-	registry.RLock()
-	defer registry.RUnlock()
+	registry.Lock()
+	defer registry.Unlock()
 	return registry.pod, registry.err
 }
 
 func (registry *MockPodRegistry) CreatePod(machine string, pod api.Pod) error {
-	registry.RLock()
-	defer registry.RUnlock()
+	registry.Lock()
+	defer registry.Unlock()
 	return registry.err
 }
 
 func (registry *MockPodRegistry) UpdatePod(pod api.Pod) error {
-	registry.RLock()
-	defer registry.RUnlock()
+	registry.Lock()
+	defer registry.Unlock()
 	return registry.err
 }
 func (registry *MockPodRegistry) DeletePod(podId string) error {
-	registry.RLock()
-	defer registry.RUnlock()
+	registry.Lock()
+	defer registry.Unlock()
 	return registry.err
 }