diff --git a/service/jni/com_android_server_TestNetworkService.cpp b/service/jni/com_android_server_TestNetworkService.cpp
index 9c7a761..a6efbc6 100644
--- a/service/jni/com_android_server_TestNetworkService.cpp
+++ b/service/jni/com_android_server_TestNetworkService.cpp
@@ -97,6 +97,7 @@
     ScopedUtfChars iface(env, jIface);
     if (!iface.c_str()) {
         jniThrowNullPointerException(env, "iface");
+        return;
     }
     setTunTapCarrierEnabledImpl(env, iface.c_str(), tunFd, enabled);
 }