src/hotspot/share/runtime/handshake.cpp

rev 51997 : [mq]: 8210303

*** 345,354 ****
--- 345,368 ----
    assert(Threads_lock->owned_by_self(), "Not holding Threads_lock.");
    return SafepointSynchronize::safepoint_safe(target, target->thread_state()) ||
           target->is_ext_suspended();
  }
  
+ static bool possibly_vmthread_can_process_handshake(JavaThread* target) {
+   switch(target->thread_state()) {
+   case _thread_in_native:
+     // native threads are safe if they have no java stack or have walkable stack
+     return !target->has_last_Java_frame() || target->frame_anchor()->walkable();
+ 
+   case _thread_blocked:
+     return true;
+ 
+   default:
+     return false;
+   }
+ }
+ 
  bool HandshakeState::claim_handshake_for_vmthread() {
    if (!_semaphore.trywait()) {
      return false;
    }
    if (has_operation()) {
*** 364,374 ****
    if (!has_operation()) {
      // JT has already cleared its handshake
      return;
    }
  
!   if (!vmthread_can_process_handshake(target)) {
      // JT is observed in an unsafe state, it must notice the handshake itself
      return;
    }
  
    // Claim the semaphore if there still an operation to be executed.
--- 378,388 ----
    if (!has_operation()) {
      // JT has already cleared its handshake
      return;
    }
  
!   if (!possibly_vmthread_can_process_handshake(target)) {
      // JT is observed in an unsafe state, it must notice the handshake itself
      return;
    }
  
    // Claim the semaphore if there still an operation to be executed.