diff --git a/WORKSPACE b/WORKSPACE
index e5f0f5119..75b45cee1 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -26,7 +26,7 @@
 #
 # A Bazel (http://bazel.io) workspace for the Google Cloud Endpoints runtime.
 
-ISTIO_PROXY = "df4b7e43aad8e8a25d83606389c41d06ecef32ac"
+ISTIO_PROXY = "cfdb30323aa72b680bab1664035a1bbc200379c0"
 
 git_repository(
     name = "nginx",
diff --git a/test/transcoding/bookstore-server.cc b/test/transcoding/bookstore-server.cc
index 5abc026a1..216004d18 100644
--- a/test/transcoding/bookstore-server.cc
+++ b/test/transcoding/bookstore-server.cc
@@ -27,6 +27,7 @@
 #include <algorithm>
 #include <iostream>
 #include <map>
+#include <mutex>
 #include <string>
 #include <vector>
 
@@ -47,6 +48,8 @@ void PrintRequest(const MessageType& message) {
   static ::google::protobuf::util::TypeResolver* type_resolver =
       ::google::protobuf::util::NewTypeResolverForDescriptorPool(
           "type.googleapis.com", message.GetDescriptor()->file()->pool());
+  static std::mutex mutex;
+  std::lock_guard<std::mutex> lock(mutex);
 
   std::string binary;
   if (!message.SerializeToString(&binary)) {