Backport f23752a

Author: duke

src/hotspot/share/jfr/jfr.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, 2025, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 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
@@ -32,6 +32,7 @@
 #include "jfr/recorder/repository/jfrEmergencyDump.hpp"
 #include "jfr/recorder/repository/jfrRepository.hpp"
 #include "jfr/recorder/service/jfrOptionSet.hpp"
+#include "jfr/recorder/service/jfrRecorderService.hpp"
 #include "jfr/support/jfrClassDefineEvent.hpp"
 #include "jfr/support/jfrKlassExtension.hpp"
 #include "jfr/support/jfrResolution.hpp"
@@ -43,6 +44,7 @@
 #include "runtime/java.hpp"
 #include "runtime/javaThread.hpp"
 
+
 bool Jfr::is_enabled() {
   return JfrRecorder::is_enabled();
 }
@@ -153,9 +155,9 @@ void Jfr::on_resolution(const Method* caller, const Method* target, TRAPS) {
 }
 #endif
 
-void Jfr::on_vm_shutdown(bool emit_old_object_samples, bool emit_event_shutdown, bool halt) {
+void Jfr::on_vm_shutdown(bool exception_handler /* false */, bool halt /* false */, bool oom /* false */) {
   if (!halt && JfrRecorder::is_recording()) {
-    JfrEmergencyDump::on_vm_shutdown(emit_old_object_samples, emit_event_shutdown);
+    JfrEmergencyDump::on_vm_shutdown(exception_handler, oom);
   }
 }
 
@@ -173,6 +175,12 @@ bool Jfr::on_start_flight_recording_option(const JavaVMOption** option, char* de
   return JfrOptionSet::parse_start_flight_recording_option(option, delimiter);
 }
 
+void Jfr::on_report_java_out_of_memory() {
+  if (CrashOnOutOfMemoryError && JfrRecorder::is_recording()) {
+    JfrRecorderService::emit_leakprofiler_events_on_oom();
+  }
+}
+
 #if INCLUDE_CDS
 void Jfr::on_restoration(const Klass* k, JavaThread* jt) {
   assert(k != nullptr, "invariant");

src/hotspot/share/jfr/jfr.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2025, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 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
@@ -71,14 +71,15 @@ class Jfr : AllStatic {
   static void on_resolution(const Method* caller, const Method* target, TRAPS);
   static void on_java_thread_start(JavaThread* starter, JavaThread* startee);
   static void on_set_current_thread(JavaThread* jt, oop thread);
-  static void on_vm_shutdown(bool emit_old_object_samples, bool emit_event_shutdown, bool halt = false);
+  static void on_vm_shutdown(bool exception_handler = false, bool halt = false, bool oom = false);
   static void on_vm_error_report(outputStream* st);
   static bool on_flight_recorder_option(const JavaVMOption** option, char* delimiter);
   static bool on_start_flight_recording_option(const JavaVMOption** option, char* delimiter);
   static void on_backpatching(const Method* callee_method, JavaThread* jt);
   static void initialize_main_thread(JavaThread* jt);
   static bool has_sample_request(JavaThread* jt);
   static void check_and_process_sample_request(JavaThread* jt);
+  static void on_report_java_out_of_memory();
   CDS_ONLY(static void on_restoration(const Klass* k, JavaThread* jt);)
 };
 

src/hotspot/share/jfr/jni/jfrJniMethod.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2025, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 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
@@ -364,8 +364,7 @@ JVM_ENTRY_NO_ENV(void, jfr_set_force_instrumentation(JNIEnv* env, jclass jvm, jb
 JVM_END
 
 NO_TRANSITION(void, jfr_emit_old_object_samples(JNIEnv* env, jclass jvm, jlong cutoff_ticks, jboolean emit_all, jboolean skip_bfs))
-  JfrRecorderService service;
-  service.emit_leakprofiler_events(cutoff_ticks, emit_all == JNI_TRUE, skip_bfs == JNI_TRUE);
+  JfrRecorderService::emit_leakprofiler_events(cutoff_ticks, emit_all == JNI_TRUE, skip_bfs == JNI_TRUE);
 NO_TRANSITION_END
 
 JVM_ENTRY_NO_ENV(void, jfr_exclude_thread(JNIEnv* env, jclass jvm, jobject t))

src/hotspot/share/jfr/recorder/repository/jfrEmergencyDump.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2025, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 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
@@ -38,6 +38,8 @@
 #include "runtime/mutexLocker.hpp"
 #include "runtime/os.hpp"
 #include "runtime/thread.inline.hpp"
+#include "runtime/vmOperations.hpp"
+#include "runtime/vmThread.hpp"
 #include "utilities/growableArray.hpp"
 #include "utilities/ostream.hpp"
 
@@ -460,15 +462,6 @@ static void release_locks(Thread* thread) {
   assert(thread != nullptr, "invariant");
   assert(!thread->is_Java_thread() || JavaThread::cast(thread)->thread_state() == _thread_in_vm, "invariant");
 
-#ifdef ASSERT
-  Mutex* owned_lock = thread->owned_locks();
-  while (owned_lock != nullptr) {
-    Mutex* next = owned_lock->next();
-    owned_lock->unlock();
-    owned_lock = next;
-  }
-#endif // ASSERT
-
   if (Threads_lock->owned_by_self()) {
     Threads_lock->unlock();
   }
@@ -550,17 +543,14 @@ class JavaThreadInVMAndNative : public StackObj {
   }
 };
 
-static void post_events(bool emit_old_object_samples, bool emit_event_shutdown, Thread* thread) {
-  if (emit_old_object_samples) {
-    LeakProfiler::emit_events(max_jlong, false, false);
-  }
-  if (emit_event_shutdown) {
+static void post_events(bool exception_handler, bool oom, Thread * thread) {
+  if (exception_handler) {
     EventShutdown e;
-    e.set_reason("VM Error");
+    e.set_reason(oom ? "CrashOnOutOfMemoryError" : "VM Error");
     e.commit();
   }
   EventDumpReason event;
-  event.set_reason(emit_old_object_samples ? "Out of Memory" : "Crash");
+  event.set_reason(exception_handler && oom ? "CrashOnOutOfMemoryError" : exception_handler ? "Crash" : "Out of Memory");
   event.set_recordingId(-1);
   event.commit();
 }
@@ -594,20 +584,40 @@ static bool guard_reentrancy() {
   return false;
 }
 
-void JfrEmergencyDump::on_vm_shutdown(bool emit_old_object_samples, bool emit_event_shutdown) {
+void JfrEmergencyDump::on_vm_shutdown(bool exception_handler, bool oom) {
   if (!guard_reentrancy()) {
     return;
   }
+
   Thread* const thread = Thread::current_or_null_safe();
   assert(thread != nullptr, "invariant");
+
+  // Ensure a JavaThread is _thread_in_vm when we make this call
+  JavaThreadInVMAndNative jtivm(thread);
+  post_events(exception_handler, oom, thread);
+
   if (thread->is_Watcher_thread()) {
-    log_info(jfr, system)("The Watcher thread crashed so no jfr emergency dump will be generated.");
+    // We cannot attempt an emergency dump using the Watcher thread
+    // because we rely on the WatcherThread task "is_error_reported()",
+    // to exit the VM after a hardcoded timeout, should the relatively
+    // risky operation of an emergency dump fail (deadlock, livelock).
+    log_warning(jfr, system)
+      ("The Watcher thread crashed so no jfr emergency dump will be generated.");
     return;
   }
-  // Ensure a JavaThread is _thread_in_vm when we make this call
-  JavaThreadInVMAndNative jtivm(thread);
+
+  if (thread->is_VM_thread()) {
+    const VM_Operation* const operation = VMThread::vm_operation();
+    if (operation != nullptr && operation->type() == VM_Operation::VMOp_JFROldObject) {
+      // We will not be able to issue a rotation because the rotation lock
+      // is held by the JFR Recorder Thread that issued the VM_Operation.
+      log_warning(jfr, system)
+        ("The VM Thread crashed as part of emitting leak profiler events so no jfr emergency dump will be generated.");
+      return;
+    }
+  }
+
   release_locks(thread);
-  post_events(emit_old_object_samples, emit_event_shutdown, thread);
 
   // if JavaThread, transition to _thread_in_native to issue a final flushpoint
   NoHandleMark nhm;

src/hotspot/share/jfr/recorder/repository/jfrEmergencyDump.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2025, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 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
@@ -39,7 +39,7 @@ class JfrEmergencyDump : AllStatic {
   static const char* chunk_path(const char* repository_path);
   static void on_vm_error(const char* repository_path);
   static void on_vm_error_report(outputStream* st, const char* repository_path);
-  static void on_vm_shutdown(bool emit_old_object_samples, bool emit_event_shutdown);
+  static void on_vm_shutdown(bool exception_handler, bool oom);
 };
 
 #endif // SHARE_JFR_RECORDER_REPOSITORY_JFREMERGENCYDUMP_HPP

src/hotspot/share/jfr/recorder/service/jfrPostBox.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013, 2025, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2013, 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
@@ -34,7 +34,8 @@
                              (MSGBIT(MSG_START))  |          \
                              (MSGBIT(MSG_CLONE_IN_MEMORY)) | \
                              (MSGBIT(MSG_VM_ERROR))        | \
-                             (MSGBIT(MSG_FLUSHPOINT))        \
+                             (MSGBIT(MSG_FLUSHPOINT))      | \
+                             (MSGBIT(MSG_EMIT_LEAKP_REFCHAINS)) \
                            )
 
 static JfrPostBox* _instance = nullptr;
@@ -165,7 +166,7 @@ void JfrPostBox::notify_waiters() {
   assert(JfrMsg_lock->owned_by_self(), "incrementing _msg_handled_serial is protected by JfrMsg_lock.");
   // Update made visible on release of JfrMsg_lock via fence instruction in Monitor::IUnlock.
   ++_msg_handled_serial;
-  JfrMsg_lock->notify();
+  JfrMsg_lock->notify_all();
 }
 
 // safeguard to ensure no threads are left waiting

src/hotspot/share/jfr/recorder/service/jfrPostBox.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2013, 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
@@ -43,6 +43,7 @@ enum JFR_Msg {
   MSG_SHUTDOWN,
   MSG_VM_ERROR,
   MSG_FLUSHPOINT,
+  MSG_EMIT_LEAKP_REFCHAINS,
   MSG_NO_OF_MSGS
 };
 
@@ -51,23 +52,25 @@ enum JFR_Msg {
  *
  *  Synchronous messages (posting thread waits for message completion):
  *
- *  MSG_CLONE_IN_MEMORY (0) ; MSGBIT(MSG_CLONE_IN_MEMORY) == (1 << 0) == 0x1
- *  MSG_START(1)            ; MSGBIT(MSG_START) == (1 << 0x1) == 0x2
- *  MSG_STOP (2)            ; MSGBIT(MSG_STOP) == (1 << 0x2) == 0x4
- *  MSG_ROTATE (3)          ; MSGBIT(MSG_ROTATE) == (1 << 0x3) == 0x8
- *  MSG_VM_ERROR (8)        ; MSGBIT(MSG_VM_ERROR) == (1 << 0x8) == 0x100
- *  MSG_FLUSHPOINT (9)     ; MSGBIT(MSG_FLUSHPOINT) == (1 << 0x9) == 0x200
+ *  MSG_CLONE_IN_MEMORY (0)      ; MSGBIT(MSG_CLONE_IN_MEMORY) == (1 << 0) == 0x1
+ *  MSG_START(1)                 ; MSGBIT(MSG_START) == (1 << 0x1) == 0x2
+ *  MSG_STOP (2)                 ; MSGBIT(MSG_STOP) == (1 << 0x2) == 0x4
+ *  MSG_ROTATE (3)               ; MSGBIT(MSG_ROTATE) == (1 << 0x3) == 0x8
+ *  MSG_VM_ERROR (8)             ; MSGBIT(MSG_VM_ERROR) == (1 << 0x8) == 0x100
+ *  MSG_FLUSHPOINT (9)           ; MSGBIT(MSG_FLUSHPOINT) == (1 << 0x9) == 0x200
+ *  MSG_EMIT_LEAKP_REFCHAINS (10); MSGBIT(MSG_EMIT_LEAKP_REFCHAINS) == (1 << 0xa) == 0x400
  *
  *  Asynchronous messages (posting thread returns immediately upon deposit):
  *
- *  MSG_FULLBUFFER (4)      ; MSGBIT(MSG_FULLBUFFER) == (1 << 0x4) == 0x10
- *  MSG_CHECKPOINT (5)      ; MSGBIT(CHECKPOINT) == (1 << 0x5) == 0x20
- *  MSG_WAKEUP (6)          ; MSGBIT(WAKEUP) == (1 << 0x6) == 0x40
- *  MSG_SHUTDOWN (7)        ; MSGBIT(MSG_SHUTDOWN) == (1 << 0x7) == 0x80
+ *  MSG_FULLBUFFER (4)           ; MSGBIT(MSG_FULLBUFFER) == (1 << 0x4) == 0x10
+ *  MSG_CHECKPOINT (5)           ; MSGBIT(CHECKPOINT) == (1 << 0x5) == 0x20
+ *  MSG_WAKEUP (6)               ; MSGBIT(WAKEUP) == (1 << 0x6) == 0x40
+ *  MSG_SHUTDOWN (7)             ; MSGBIT(MSG_SHUTDOWN) == (1 << 0x7) == 0x80
  */
 
 class JfrPostBox : public JfrCHeapObj {
   friend class JfrRecorder;
+  friend class JfrRecorderService;
  public:
   void post(JFR_Msg msg);