diff -r e43050e1b17f -r e704f55561c3 hotspot/src/share/vm/classfile/systemDictionary.cpp
--- a/hotspot/src/share/vm/classfile/systemDictionary.cpp	Wed Aug 30 15:48:47 2017 +0200
+++ b/hotspot/src/share/vm/classfile/systemDictionary.cpp	Wed Aug 30 19:18:22 2017 -0400
@@ -910,12 +910,9 @@
   if (protection_domain() == NULL) return k;
 
   // Check the protection domain has the right access
-  {
-    MutexLocker mu(SystemDictionary_lock, THREAD);
-    if (dictionary->is_valid_protection_domain(d_index, d_hash, name,
-                                               protection_domain)) {
-      return k;
-    }
+  if (dictionary->is_valid_protection_domain(d_index, d_hash, name,
+                                             protection_domain)) {
+    return k;
   }
 
   // Verify protection domain. If it fails an exception is thrown