diff a/src/hotspot/share/gc/shenandoah/shenandoahOldGC.cpp b/src/hotspot/share/gc/shenandoah/shenandoahOldGC.cpp
--- a/src/hotspot/share/gc/shenandoah/shenandoahOldGC.cpp
+++ b/src/hotspot/share/gc/shenandoah/shenandoahOldGC.cpp
@@ -134,10 +134,17 @@
   // return from here with weak roots in progress. This is not a valid gc state
   // for any young collections (or allocation failures) that interrupt the old
   // collection.
   heap->concurrent_final_roots();
 
+  // Arm the nmethods to possibly flip the barriers to idle.
+  vmop_entry_final_verify();
+
+  // Now we are back at concurrent phase, process nmethods to fix their barriers.
+  // TODO: Is this really safe to do when we overlap with young GC?
+  ShenandoahCodeRoots::disarm_nmethods();
+
   // After concurrent old marking finishes, we reclaim immediate garbage. Further, we may also want to expand OLD in order
   // to make room for anticipated promotions and/or for mixed evacuations.  Mixed evacuations are especially likely to
   // follow the end of OLD marking.
   heap->rebuild_free_set_within_phase();
   heap->free_set()->log_status_under_lock();