diff --git a/src/hotspot/share/cds/cdsConfig.cpp b/src/hotspot/share/cds/cdsConfig.cpp
index d3048b9ee7a..0505ae20a78 100644
--- a/src/hotspot/share/cds/cdsConfig.cpp
+++ b/src/hotspot/share/cds/cdsConfig.cpp
@@ -862,7 +862,11 @@ CDSConfig::DumperThreadMark::~DumperThreadMark() {
 
 bool CDSConfig::current_thread_is_vm_or_dumper() {
   Thread* t = Thread::current();
-  return t != nullptr && (t->is_VM_thread() || t == _dumper_thread);
+  return t->is_VM_thread() || t == _dumper_thread;
+}
+
+bool CDSConfig::current_thread_is_dumper() {
+  return Thread::current() == _dumper_thread;
 }
 
 const char* CDSConfig::type_of_archive_being_loaded() {
diff --git a/src/hotspot/share/cds/cdsConfig.hpp b/src/hotspot/share/cds/cdsConfig.hpp
index 8361cf052db..cfa846f2b41 100644
--- a/src/hotspot/share/cds/cdsConfig.hpp
+++ b/src/hotspot/share/cds/cdsConfig.hpp
@@ -216,6 +216,7 @@ public:
     ~DumperThreadMark();
   };
 
+  static bool current_thread_is_dumper() NOT_CDS_RETURN_(false);
   static bool current_thread_is_vm_or_dumper() NOT_CDS_RETURN_(false);
 };
 
diff --git a/src/hotspot/share/cds/lambdaFormInvokers.cpp b/src/hotspot/share/cds/lambdaFormInvokers.cpp
index e8900f43d43..946599dddbf 100644
--- a/src/hotspot/share/cds/lambdaFormInvokers.cpp
+++ b/src/hotspot/share/cds/lambdaFormInvokers.cpp
@@ -53,6 +53,7 @@
 
 GrowableArrayCHeap<char*, mtClassShared>* LambdaFormInvokers::_lambdaform_lines = nullptr;
 Array<u4>*  LambdaFormInvokers::_static_archive_invokers = nullptr;
+static bool _stop_appending = false;
 
 #define NUM_FILTER 4
 static const char* filter[NUM_FILTER] = {"java.lang.invoke.Invokers$Holder",
@@ -71,7 +72,12 @@ static bool should_be_archived(char* line) {
 #undef NUM_FILTER
 
 void LambdaFormInvokers::append(char* line) {
+  // This function can be called by concurrent Java threads, even after
+  // LambdaFormInvokers::regenerate_holder_classes() has been called.
   MutexLocker ml(Thread::current(), LambdaFormInvokers_lock);
+  if (_stop_appending) {
+    return;
+  }
   if (_lambdaform_lines == nullptr) {
     _lambdaform_lines = new GrowableArrayCHeap<char*, mtClassShared>(150);
   }
@@ -112,12 +118,6 @@ void LambdaFormInvokers::regenerate_holder_classes(TRAPS) {
     return;
   }
 
-  PrintLambdaFormMessage plm;
-  if (_lambdaform_lines == nullptr || _lambdaform_lines->length() == 0) {
-    log_info(aot)("Nothing to regenerate for holder classes");
-    return;
-  }
-
   ResourceMark rm(THREAD);
 
   // Filter out AOT tooling classes like java.lang.invoke.GenerateJLIClassesHelper, etc.
@@ -127,18 +127,27 @@ void LambdaFormInvokers::regenerate_holder_classes(TRAPS) {
   Klass*  cds_klass = SystemDictionary::resolve_or_null(cds_name, THREAD);
   guarantee(cds_klass != nullptr, "jdk/internal/misc/CDS must exist!");
 
+  assert(CDSConfig::current_thread_is_dumper(), "not supposed to be called from other threads");
+  {
+    // Stop other threads from recording into _lambdaform_lines.
+    MutexLocker ml(Thread::current(), LambdaFormInvokers_lock);
+    _stop_appending = true;
+  }
+
+  PrintLambdaFormMessage plm;
+  if (_lambdaform_lines == nullptr || _lambdaform_lines->length() == 0) {
+    log_info(aot)("Nothing to regenerate for lambda form holder classes");
+    return;
+  }
+
   HandleMark hm(THREAD);
   int len = _lambdaform_lines->length();
-  objArrayHandle list_lines;
-  {
-    MutexLocker ml(Thread::current(), LambdaFormInvokers_lock);
-    list_lines = oopFactory::new_objArray_handle(vmClasses::String_klass(), len, CHECK);
-    for (int i = 0; i < len; i++) {
-      Handle h_line = java_lang_String::create_from_str(_lambdaform_lines->at(i), CHECK);
-      list_lines->obj_at_put(i, h_line());
-    }
-  } // Before calling into java, release vm lock.
-  //
+  objArrayHandle list_lines = oopFactory::new_objArray_handle(vmClasses::String_klass(), len, CHECK);
+  for (int i = 0; i < len; i++) {
+    Handle h_line = java_lang_String::create_from_str(_lambdaform_lines->at(i), CHECK);
+    list_lines->obj_at_put(i, h_line());
+  }
+
   // Object[] CDS.generateLambdaFormHolderClasses(String[] lines)
   // the returned Object[] layout:
   //   name, byte[], name, byte[] ....
@@ -232,6 +241,7 @@ void LambdaFormInvokers::regenerate_class(char* class_name, ClassFileStream& st,
 }
 
 void LambdaFormInvokers::dump_static_archive_invokers() {
+  assert(SafepointSynchronize::is_at_safepoint(), "no concurrent update to _lambdaform_lines");
   if (_lambdaform_lines != nullptr && _lambdaform_lines->length() > 0) {
     int count = 0;
     int len   = _lambdaform_lines->length();