--- a/src/hotspot/share/runtime/os.cpp	Wed Mar 06 12:14:47 2019 +0100
+++ b/src/hotspot/share/runtime/os.cpp	Thu Feb 28 14:22:03 2019 +0100
@@ -873,6 +873,8 @@
 void os::print_hex_dump(outputStream* st, address start, address end, int unitsize) {
   assert(unitsize == 1 || unitsize == 2 || unitsize == 4 || unitsize == 8, "just checking");
 
+  start = align_down(start, unitsize);
+
   int cols = 0;
   int cols_per_line = 0;
   switch (unitsize) {