--- a/src/hotspot/share/memory/filemap.cpp	Thu Jul 12 16:30:47 2018 +0200
+++ b/src/hotspot/share/memory/filemap.cpp	Wed Jul 11 16:11:10 2018 +0200
@@ -631,7 +631,9 @@
   si->_read_only = read_only;
   si->_allow_exec = allow_exec;
   si->_crc = ClassLoader::crc32(0, base, (jint)size);
-  write_bytes_aligned(base, (int)size);
+  if (base != NULL) {
+    write_bytes_aligned(base, (int)size);
+  }
 }
 
 // Write out the given archive heap memory regions.  GC code combines multiple