--- a/src/hotspot/share/classfile/moduleEntry.cpp	Thu Jul 12 16:30:47 2018 +0200
+++ b/src/hotspot/share/classfile/moduleEntry.cpp	Wed Jul 11 16:11:10 2018 +0200
@@ -387,7 +387,8 @@
     entry->set_is_patched();
     if (log_is_enabled(Trace, module, patch)) {
       ResourceMark rm;
-      log_trace(module, patch)("Marked module %s as patched from --patch-module", name->as_C_string());
+      log_trace(module, patch)("Marked module %s as patched from --patch-module",
+                               name != NULL ? name->as_C_string() : UNNAMED_MODULE);
     }
   }