--- old/src/hotspot/share/runtime/objectMonitor.cpp	2019-08-28 15:03:29.370958452 -0400
+++ new/src/hotspot/share/runtime/objectMonitor.cpp	2019-08-28 15:03:29.186958458 -0400
@@ -2111,6 +2111,13 @@
       om_ptr->dec_ref_count();
       return false;
     }
+    if (om_ptr->ref_count() <= 0) {
+      // Async deflation is in the process of bailing out, but has not
+      // yet restored the ref_count field so we return false to force
+      // a retry. We want a positive ref_count value for a true return.
+      om_ptr->dec_ref_count();
+      return false;
+    }
     // The ObjectMonitor could have been deflated and reused for
     // another object before we bumped the ref_count so make sure
     // our object still refers to this ObjectMonitor.