From 636b56374e4617ebd28c69ccac71fbf29dfd648e Mon Sep 17 00:00:00 2001
From: William Kemper <wkemper@openjdk.org>
Date: Mon, 23 Jun 2025 21:03:04 +0000
Subject: [PATCH] 8357550: GenShen crashes during freeze:
 assert(!chunk->requires_barriers()) failed

Reviewed-by: shade
Backport-of: 17cf49746d0c289bdf779c974cdc84a3ab32ab4b
---
 .../shenandoah/shenandoahGenerationalHeap.cpp | 23 +++++++++++++++++++
 .../shenandoah/shenandoahGenerationalHeap.hpp |  2 ++
 2 files changed, 25 insertions(+)

diff --git a/src/hotspot/share/gc/shenandoah/shenandoahGenerationalHeap.cpp b/src/hotspot/share/gc/shenandoah/shenandoahGenerationalHeap.cpp
index 1f84feb20e8..731868310f4 100644
--- a/src/hotspot/share/gc/shenandoah/shenandoahGenerationalHeap.cpp
+++ b/src/hotspot/share/gc/shenandoah/shenandoahGenerationalHeap.cpp
@@ -183,6 +183,29 @@ void ShenandoahGenerationalHeap::stop() {
   regulator_thread()->stop();
 }
 
+bool ShenandoahGenerationalHeap::requires_barriers(stackChunkOop obj) const {
+  if (is_idle()) {
+    return false;
+  }
+
+  if (is_concurrent_young_mark_in_progress() && is_in_young(obj) && !marking_context()->allocated_after_mark_start(obj)) {
+    // We are marking young, this object is in young, and it is below the TAMS
+    return true;
+  }
+
+  if (is_in_old(obj)) {
+    // Card marking barriers are required for objects in the old generation
+    return true;
+  }
+
+  if (has_forwarded_objects()) {
+    // Object may have pointers that need to be updated
+    return true;
+  }
+
+  return false;
+}
+
 void ShenandoahGenerationalHeap::evacuate_collection_set(bool concurrent) {
   ShenandoahRegionIterator regions;
   ShenandoahGenerationalEvacuationTask task(this, &regions, concurrent, false /* only promote regions */);
diff --git a/src/hotspot/share/gc/shenandoah/shenandoahGenerationalHeap.hpp b/src/hotspot/share/gc/shenandoah/shenandoahGenerationalHeap.hpp
index cef5dfd7070..ed5a6f3d9a5 100644
--- a/src/hotspot/share/gc/shenandoah/shenandoahGenerationalHeap.hpp
+++ b/src/hotspot/share/gc/shenandoah/shenandoahGenerationalHeap.hpp
@@ -128,6 +128,8 @@ public:
 
   void stop() override;
 
+  bool requires_barriers(stackChunkOop obj) const override;
+
   // Used for logging the result of a region transfer outside the heap lock
   struct TransferResult {
     bool success;