src/share/vm/runtime/thread.cpp

*** 3390,3399 ****
--- 3390,3406 ----
    ALL_JAVA_THREADS(p) {
      if (p->claim_oops_do(true, cp)) {
        tc->do_thread(p);
      }
    }
+   // Thread claiming protocol requires us to claim the same interesting
+   // threads on all paths. Notably, Threads::possibly_parallel_threads_do
+   // claims all Java threads *and* the VMThread. To avoid breaking the
+   // claiming protocol, we have to claim VMThread on this path too, even
+   // if we do not apply the closure to the VMThread.
+   VMThread* vmt = VMThread::vm_thread();
+   (void)vmt->claim_oops_do(true, cp);
  }
  
  // The system initialization in the library has three phases.
  //
  // Phase 1: java.lang.System class initialization
*** 4355,4364 ****
--- 4362,4375 ----
    ALL_JAVA_THREADS(p) {
      const int thread_parity = p->oops_do_parity();
      assert((thread_parity == _thread_claim_parity),
             "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity);
    }
+   VMThread* vmt = VMThread::vm_thread();
+   const int thread_parity = vmt->oops_do_parity();
+   assert((thread_parity == _thread_claim_parity),
+          "VMThread " PTR_FORMAT " has incorrect parity %d != %d", p2i(vmt), thread_parity, _thread_claim_parity);
  }
  #endif // ASSERT
  
  void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
    int cp = Threads::thread_claim_parity();