src/hotspot/share/prims/whitebox.cpp

*** 427,11 ***
      return ZHeap::heap()->is_old(to_zaddress(p));
    }
  #endif
  #if INCLUDE_SHENANDOAHGC
    if (UseShenandoahGC) {
!     return Universe::heap()->is_in(p);
    }
  #endif
  #if INCLUDE_SERIALGC
    if (UseSerialGC) {
      return !SerialHeap::heap()->is_in_young(p);
--- 427,12 ---
      return ZHeap::heap()->is_old(to_zaddress(p));
    }
  #endif
  #if INCLUDE_SHENANDOAHGC
    if (UseShenandoahGC) {
!     ShenandoahHeap* sh = ShenandoahHeap::heap();
+     return sh->mode()->is_generational() ?  sh->is_in_old(p) : sh->is_in(p);
    }
  #endif
  #if INCLUDE_SERIALGC
    if (UseSerialGC) {
      return !SerialHeap::heap()->is_in_young(p);