diff --git a/src/hotspot/share/runtime/mutex.cpp b/src/hotspot/share/runtime/mutex.cpp
index c455b5f36a2..8e0c1d10e5c 100644
--- a/src/hotspot/share/runtime/mutex.cpp
+++ b/src/hotspot/share/runtime/mutex.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2025, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2026, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -293,7 +293,8 @@ Mutex::Mutex(Rank rank, const char * name, bool allow_vm_block) : _owner(nullptr
   _rank            = rank;
   _skip_rank_check = false;
 
-  assert(_rank >= static_cast<Rank>(0) && _rank <= safepoint, "Bad lock rank %s: %s", rank_name(), name);
+  assert(_rank >= static_cast<Rank>(0) && _rank <= safepoint, "Bad lock rank %d outside [0, %d]: %s",
+         static_cast<int>(rank), static_cast<int>(safepoint), name);
 
   // The allow_vm_block also includes allowing other non-Java threads to block or
   // allowing Java threads to block in native.
@@ -324,25 +325,33 @@ static const char* _rank_names[] = { "event", "service", "stackwatermark", "tty"
 
 static const int _num_ranks = 7;
 
-static const char* rank_name_internal(Mutex::Rank r) {
+static void print_rank_name_internal(outputStream* st, Mutex::Rank r) {
   // Find closest rank and print out the name
-  stringStream st;
   for (int i = 0; i < _num_ranks; i++) {
     if (r == _ranks[i]) {
-      return _rank_names[i];
+      st->print("%s", _rank_names[i]);
     } else if (r  > _ranks[i] && (i < _num_ranks-1 && r < _ranks[i+1])) {
       int delta = static_cast<int>(_ranks[i+1]) - static_cast<int>(r);
-      st.print("%s-%d", _rank_names[i+1], delta);
-      return st.as_string();
+      st->print("%s-%d", _rank_names[i+1], delta);
     }
   }
-  return "fail";
+}
+
+// Requires caller to have ResourceMark.
+static const char* rank_name_internal(Mutex::Rank r) {
+  stringStream st;
+  print_rank_name_internal(&st, r);
+  return st.as_string();
 }
 
 const char* Mutex::rank_name() const {
   return rank_name_internal(_rank);
 }
 
+// Does not require caller to have ResourceMark.
+void Mutex::print_rank_name(outputStream* st) const {
+  print_rank_name_internal(st, _rank);
+}
 
 void Mutex::assert_no_overlap(Rank orig, Rank adjusted, int adjust) {
   int i = 0;
@@ -364,7 +373,8 @@ void Mutex::print_on(outputStream* st) const {
   if (_allow_vm_block) {
     st->print("%s", " allow_vm_block");
   }
-  DEBUG_ONLY(st->print(" %s", rank_name()));
+  st->print(" ");
+  DEBUG_ONLY(print_rank_name(st));
   st->cr();
 }
 
diff --git a/src/hotspot/share/runtime/mutex.hpp b/src/hotspot/share/runtime/mutex.hpp
index cf2b222d2da..4d30a320cbf 100644
--- a/src/hotspot/share/runtime/mutex.hpp
+++ b/src/hotspot/share/runtime/mutex.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2025, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2026, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -130,9 +130,11 @@ class Mutex : public CHeapObj<mtSynchronizer> {
     return _skip_rank_check;
   }
 
+  const char* rank_name() const;
+  void print_rank_name(outputStream* st) const;
+
  public:
   Rank   rank() const          { return _rank; }
-  const char*  rank_name() const;
   Mutex* next()  const         { return _next; }
 #endif // ASSERT
 
diff --git a/test/hotspot/gtest/runtime/test_mutex.cpp b/test/hotspot/gtest/runtime/test_mutex.cpp
index 2ed7b1b3a34..64b7a5207d7 100644
--- a/test/hotspot/gtest/runtime/test_mutex.cpp
+++ b/test/hotspot/gtest/runtime/test_mutex.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, 2025, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2026, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -323,11 +323,12 @@ TEST_VM_ASSERT_MSG(MutexSafepoint, possible_safepoint_lock,
     ".* Possible safepoint reached by thread that does not allow it") {
   JavaThread* thread = JavaThread::current();
   ThreadInVMfromNative in_native(thread);
-  MutexLocker ml(new Mutex(Mutex::nosafepoint, "SpecialTest_lock"),
+  MutexLocker ml(new Mutex(Mutex::nosafepoint-2, "SpecialTest_lock"),
                    Mutex::_no_safepoint_check_flag);
   thread->print_thread_state_on(tty);
   // If the lock above succeeds, try to safepoint to test the NSV implied with this nosafepoint lock.
   ThreadBlockInVM tbivm(thread);
   thread->print_thread_state_on(tty);
 }
+
 #endif // ASSERT