--- old/src/hotspot/share/gc/g1/heapRegion.cpp	2019-12-04 15:39:03.462679107 +0100
+++ new/src/hotspot/share/gc/g1/heapRegion.cpp	2019-12-04 15:39:03.258677552 +0100
@@ -119,6 +119,7 @@
   clear_young_index_in_cset();
   clear_index_in_opt_cset();
   uninstall_surv_rate_group();
+  _survivor_bytes = 0;
   set_free();
   reset_pre_dummy_top();
 
@@ -251,6 +252,7 @@
 #endif
   _prev_top_at_mark_start(NULL), _next_top_at_mark_start(NULL),
   _prev_marked_bytes(0), _next_marked_bytes(0),
+  _survivor_bytes(0),
   _young_index_in_cset(-1),
   _surv_rate_group(NULL), _age_index(G1SurvRateGroup::InvalidAgeIndex), _gc_efficiency(0.0),
   _node_index(G1NUMA::UnknownNodeIndex)