src/hotspot/share/runtime/handshake.cpp

rev 51997 : [mq]: 8210303

@@ -345,10 +345,24 @@
   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()) {

@@ -364,11 +378,11 @@
   if (!has_operation()) {
     // JT has already cleared its handshake
     return;
   }
 
-  if (!vmthread_can_process_handshake(target)) {
+  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.