8278987: RunThese24H.java failed with EXCEPTION_ACCESS_VIOLATION in __write_sample_info__

Reviewed-by: jbachorik

Author: Markus Grönlund

src/hotspot/share/jfr/leakprofiler/checkpoint/objectSampleCheckpoint.cpp

@@ -202,7 +202,7 @@ static void prepare_for_resolution() {
 
 static bool stack_trace_precondition(const ObjectSample* sample) {
   assert(sample != NULL, "invariant");
-  return sample->has_stack_trace_id() && !sample->is_dead() && !sample->stacktrace().valid();
+  return sample->has_stack_trace_id() && !sample->is_dead();
 }
 
 class StackTraceBlobInstaller {
@@ -249,7 +249,7 @@ void StackTraceBlobInstaller::install(ObjectSample* sample) {
   writer.write_type(TYPE_STACKTRACE);
   writer.write_count(1);
   ObjectSampleCheckpoint::write_stacktrace(stack_trace, writer);
-  blob = writer.move();
+  blob = writer.copy();
   _cache.put(sample, blob);
   sample->set_stacktrace(blob);
 }
@@ -278,7 +278,7 @@ void ObjectSampleCheckpoint::on_rotation(const ObjectSampler* sampler) {
 }
 
 static bool is_klass_unloaded(traceid klass_id) {
-  assert_locked_or_safepoint(ClassLoaderDataGraph_lock);
+  assert(ClassLoaderDataGraph_lock->owned_by_self(), "invariant");
   return JfrKlassUnloading::is_unloaded(klass_id);
 }
 
@@ -381,12 +381,6 @@ void ObjectSampleCheckpoint::write(const ObjectSampler* sampler, EdgeStore* edge
   assert(sampler != NULL, "invariant");
   assert(edge_store != NULL, "invariant");
   assert(thread != NULL, "invariant");
-  {
-    // First install stacktrace blobs for the most recently added candidates.
-    MutexLocker lock(SafepointSynchronize::is_at_safepoint() ? nullptr : ClassLoaderDataGraph_lock);
-    // the lock is needed to ensure the unload lists do not grow in the middle of inspection.
-    install_stack_traces(sampler);
-  }
   write_sample_blobs(sampler, emit_all, thread);
   // write reference chains
   if (!edge_store->is_empty()) {