src/share/vm/services/threadService.cpp

rev 4818 : 8016304: ThreadMXBean.getDeadlockedThreads reports bogus deadlocks on JDK 8
Reviewed-by:

*** 325,336 ****
        waitingToLockBlocker = jt->current_park_blocker();
      }
      while (waitingToLockMonitor != NULL || waitingToLockBlocker != NULL) {
        cycle->add_thread(currentThread);
        if (waitingToLockMonitor != NULL) {
          currentThread = Threads::owning_thread_from_monitor_owner(
!                           (address)waitingToLockMonitor->owner(),
                            false /* no locking needed */);
          if (currentThread == NULL) {
            // This function is called at a safepoint so the JavaThread
            // that owns waitingToLockMonitor should be findable, but
            // if it is not findable, then the previous currentThread is
--- 325,338 ----
        waitingToLockBlocker = jt->current_park_blocker();
      }
      while (waitingToLockMonitor != NULL || waitingToLockBlocker != NULL) {
        cycle->add_thread(currentThread);
        if (waitingToLockMonitor != NULL) {
+         address currentOwner = (address)waitingToLockMonitor->owner();
+         if (currentOwner != NULL) {
            currentThread = Threads::owning_thread_from_monitor_owner(
!                             currentOwner,
                              false /* no locking needed */);
            if (currentThread == NULL) {
              // This function is called at a safepoint so the JavaThread
              // that owns waitingToLockMonitor should be findable, but
              // if it is not findable, then the previous currentThread is
*** 347,356 ****
--- 349,359 ----
              }
              last = cycle;
              cycle = new DeadlockCycle();
              break;
            }
+         }
        } else {
          if (concurrent_locks) {
            if (waitingToLockBlocker->is_a(SystemDictionary::abstract_ownable_synchronizer_klass())) {
              oop threadObj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(waitingToLockBlocker);
              currentThread = threadObj != NULL ? java_lang_Thread::thread(threadObj) : NULL;