--- old/src/share/vm/gc/g1/concurrentMark.cpp	2015-11-05 13:45:01.206427904 +0100
+++ new/src/share/vm/gc/g1/concurrentMark.cpp	2015-11-05 13:45:01.110427428 +0100
@@ -1433,12 +1433,25 @@
     size_t exp_marked_bytes = _calc_cl.region_marked_bytes();
     size_t act_marked_bytes = hr->next_marked_bytes();
 
-    // We're not OK if expected marked bytes > actual marked bytes. It means
-    // we have missed accounting some objects during the actual marking.
-    // For start_humongous regions, the size of the whole object will be
-    // in exp_marked_bytes, so this check does not apply in this case.
-    if (exp_marked_bytes > act_marked_bytes && !hr->is_starts_humongous()) {
-      failures += 1;
+    if (exp_marked_bytes > act_marked_bytes) {
+      if (hr->is_starts_humongous()) {
+        // For start_humongous regions, the size of the whole object will be
+        // in exp_marked_bytes.
+        HeapRegion* region = hr;
+        int num_regions;
+        for (num_regions = 0; region != NULL; num_regions++) {
+          region = _g1h->next_region_in_humongous(region);
+        }
+        if ((num_regions-1) * HeapRegion::GrainBytes >= exp_marked_bytes) {
+          failures += 1;
+        } else if (num_regions * HeapRegion::GrainBytes < exp_marked_bytes) {
+          failures += 1;
+        }
+      } else {
+        // We're not OK if expected marked bytes > actual marked bytes. It means
+        // we have missed accounting some objects during the actual marking.
+        failures += 1;
+      }
     }
 
     // Verify the bit, for this region, in the actual and expected