Don't try to setup_jvmti_thread_state for obj allocation sampling if …

…the current thread is attaching from native and is allocating the thread oop. That's to make sure we don't create a 'partial' JvmtiThreadState.

src/hotspot/share/prims/jvmtiExport.cpp

@@ -3139,6 +3139,15 @@ bool JvmtiSampledObjectAllocEventCollector::object_alloc_is_safe_to_sample() {
     return false;
   }
 
+  // If the current thread is attaching from native and its thread oop is being
+  // allocated, things are not ready for allocation sampling.
+  if (thread->is_Java_thread()) {
+    JavaThread* jt = JavaThread::cast(thread);
+    if (jt->is_attaching_via_jni() && jt->threadObj() == nullptr) {
+      return false;
+    }
+  }
+
   if (MultiArray_lock->owner() == thread) {
     return false;
   }

src/hotspot/share/prims/jvmtiThreadState.inline.hpp

@@ -86,14 +86,20 @@ inline JvmtiThreadState* JvmtiThreadState::state_for_while_locked(JavaThread *th
     return nullptr;
   }
 
+#ifdef ASSERT
+  // Make sure we don't see an incomplete state. An incomplete state can cause
+  // a duplicate JvmtiThreadState being created below and bound to the 'thread'
+  // incorrectly, which leads to stale JavaThread* from the JvmtiThreadState
+  // after the thread exits.
+  if (state != nullptr) {
+    assert(state->get_thread_oop() != nullptr, "incomplete state");
+  }
+#endif
+
   if (thread_oop == nullptr) {  // Then thread should not be null (see assert above).
     thread_oop = thread->jvmti_vthread() != nullptr ? thread->jvmti_vthread() : thread->threadObj();
   }
-  // The state->get_thread_oop() may be null if the state is created during
-  // the allocation of the thread oop when a native thread is attaching. Make
-  // sure we don't create a new state for the JavaThread.
-  if (state == nullptr || (state->get_thread_oop() != nullptr &&
-                           state->get_thread_oop() != thread_oop)) {
+  if (state == nullptr || state->get_thread_oop() != thread_oop) {
     // Check if java_lang_Thread already has a link to the JvmtiThreadState.
     if (thread_oop != nullptr) {  // thread_oop can be null during early VMStart.
       state = java_lang_Thread::jvmti_thread_state(thread_oop);