diff --git a/services/surfaceflinger/GpuService.cpp b/services/surfaceflinger/GpuService.cpp
index b993dfb..dc1d3f0 100644
--- a/services/surfaceflinger/GpuService.cpp
+++ b/services/surfaceflinger/GpuService.cpp
@@ -71,12 +71,15 @@
     for (size_t i = 0, n = args.size(); i < n; i++)
         ALOGV("  arg[%zu]: '%s'", i, String8(args[i]).string());
 
-    if (args[0] == String16("vkjson"))
-        return cmd_vkjson(out, err);
-    else if (args[0] == String16("help"))
-        return cmd_help(out);
-
-    return NO_ERROR;
+    if (args.size() >= 1) {
+        if (args[0] == String16("vkjson"))
+            return cmd_vkjson(out, err);
+        if (args[0] == String16("help"))
+            return cmd_help(out);
+    }
+    // no command, or unrecognized command
+    cmd_help(err);
+    return BAD_VALUE;
 }
 
 // ----------------------------------------------------------------------------