diff -r 5ff7480c9e28 -r 9a8585f60c32 src/hotspot/share/gc/z/zCollectedHeap.cpp
--- a/src/hotspot/share/gc/z/zCollectedHeap.cpp	Tue Dec 11 11:29:28 2018 +0100
+++ b/src/hotspot/share/gc/z/zCollectedHeap.cpp	Tue Dec 11 11:08:39 2018 +0100
@@ -259,12 +259,10 @@
 }
 
 void ZCollectedHeap::register_nmethod(nmethod* nm) {
-  assert_locked_or_safepoint(CodeCache_lock);
   ZNMethodTable::register_nmethod(nm);
 }
 
 void ZCollectedHeap::unregister_nmethod(nmethod* nm) {
-  assert_locked_or_safepoint(CodeCache_lock);
   ZNMethodTable::unregister_nmethod(nm);
 }