src/share/vm/prims/jvmtiEnv.cpp

*** 1358,1369 ****
    // retrieve or create JvmtiThreadState.
    JvmtiThreadState* state = JvmtiThreadState::state_for(java_thread);
    if (state == NULL) {
      return JVMTI_ERROR_THREAD_NOT_ALIVE;
    }
!   uint32_t debug_bits = 0;
!   if (is_thread_fully_suspended(java_thread, true, &debug_bits)) {
      err = get_frame_count(state, count_ptr);
    } else {
      // get java stack frame count at safepoint.
      VM_GetFrameCount op(this, state, count_ptr);
      VMThread::execute(&op);
--- 1358,1372 ----
    // retrieve or create JvmtiThreadState.
    JvmtiThreadState* state = JvmtiThreadState::state_for(java_thread);
    if (state == NULL) {
      return JVMTI_ERROR_THREAD_NOT_ALIVE;
    }
! 
!   // Performance-wise the only important case is when current thread is
!   // the target thread. Otherwise, it is Ok and more safe to get frame
!   // count at a safepoint, even if the target thread is suspended.
!   if (java_thread == JavaThread::current()) {
      err = get_frame_count(state, count_ptr);
    } else {
      // get java stack frame count at safepoint.
      VM_GetFrameCount op(this, state, count_ptr);
      VMThread::execute(&op);