From 491b3b45634fffb0101244f7d491a1681e7e8002 Mon Sep 17 00:00:00 2001
From: William Kemper <wkemper@openjdk.org>
Date: Wed, 15 May 2024 16:53:04 +0000
Subject: [PATCH] 8332256: Shenandoah: Do not visit heap threads during
 shutdown

Reviewed-by: shade, kdnilsen
---
 src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp b/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp
index 870885b385c..53d4911797d 100644
--- a/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp
+++ b/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp
@@ -1291,7 +1291,14 @@ void ShenandoahHeap::prepare_for_verify() {
 }
 
 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
-  tcl->do_thread(_control_thread);
+  if (_shenandoah_policy->is_at_shutdown()) {
+    return;
+  }
+
+  if (_control_thread != nullptr) {
+    tcl->do_thread(_control_thread);
+  }
+
   workers()->threads_do(tcl);
   if (_safepoint_workers != nullptr) {
     _safepoint_workers->threads_do(tcl);
@@ -1848,7 +1855,7 @@ uint ShenandoahHeap::max_workers() {
 void ShenandoahHeap::stop() {
   // The shutdown sequence should be able to terminate when GC is running.
 
-  // Step 0. Notify policy to disable event recording.
+  // Step 0. Notify policy to disable event recording and prevent visiting gc threads during shutdown
   _shenandoah_policy->record_shutdown();
 
   // Step 1. Notify control thread that we are in shutdown.