diff --git a/ethereum/stat/stat_recorder_test.go b/ethereum/stat/stat_recorder_test.go
index a57a1fa..cf9808c 100644
--- a/ethereum/stat/stat_recorder_test.go
+++ b/ethereum/stat/stat_recorder_test.go
@@ -10,8 +10,8 @@ import (
 	"time"
 )
 
-var rig *ethereum.Rig = ethereum.NewRig("testrig")
-var rig2 *ethereum.Rig = ethereum.NewRig("anotherrig")
+var rig *ethereum.Rig = ethereum.NewRig("testrig", "192.168.1.2")
+var rig2 *ethereum.Rig = ethereum.NewRig("anotherrig", "192.168.1.3")
 
 func newStatRecorder() *StatRecorder {
 	return &StatRecorder{
diff --git a/protocol/test_rig.go b/protocol/test_rig.go
index aa62f13..f30997c 100644
--- a/protocol/test_rig.go
+++ b/protocol/test_rig.go
@@ -6,3 +6,7 @@ type testRig struct {
 func (r *testRig) ID() string {
 	return "rig"
 }
+
+func (r *testRig) IP() string {
+	return "127.0.0.1"
+}
diff --git a/run_test.sh b/run_test.sh
index b73a530..91d4a3f 100755
--- a/run_test.sh
+++ b/run_test.sh
@@ -1 +1 @@
-build/env.sh go test -ldflags -s `go list ./... | grep -v vendor | grep -v experiment`
+build/env.sh go test -ldflags -s `go list ./... | grep -v vendor | grep -v experiment | grep -v ethash`
diff --git a/storage/gob_file_storage.go b/storage/gob_file_storage.go
index 81ef9d7..0973e28 100644
--- a/storage/gob_file_storage.go
+++ b/storage/gob_file_storage.go
@@ -77,8 +77,6 @@ func getName(value interface{}) string {
 }
 
 func (gfs *GobFileStorage) register(value interface{}) {
-	gfs.mu.Lock()
-	defer gfs.mu.Unlock()
 	name := getName(value)
 	if _, found := gfs.registeredType[name]; !found {
 		gob.Register(value)
@@ -102,6 +100,8 @@ func (gfs *GobFileStorage) persistToFile(data interface{}, id string) error {
 }
 
 func (gfs *GobFileStorage) Persist(data interface{}, id string) error {
+	gfs.mu.Lock()
+	defer gfs.mu.Unlock()
 	if err := gfs.persistToFile(data, id); err != nil {
 		return err
 	}
@@ -109,6 +109,8 @@ func (gfs *GobFileStorage) Persist(data interface{}, id string) error {
 }
 
 func (gfs *GobFileStorage) Load(data interface{}, id string) (interface{}, error) {
+	gfs.mu.Lock()
+	defer gfs.mu.Unlock()
 	f, err := os.Open(getFile(id))
 	if err != nil {
 		return data, err