1 /*
2 * Copyright (c) 1997, 2025, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2021, Azul Systems, Inc. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "precompiled.hpp"
27 #include "cds/dynamicArchive.hpp"
28 #include "ci/ciEnv.hpp"
29 #include "classfile/javaClasses.inline.hpp"
30 #include "classfile/javaThreadStatus.hpp"
31 #include "classfile/systemDictionary.hpp"
32 #include "classfile/vmClasses.hpp"
33 #include "classfile/vmSymbols.hpp"
34 #include "code/codeCache.hpp"
35 #include "code/scopeDesc.hpp"
36 #include "compiler/compileTask.hpp"
37 #include "compiler/compilerThread.hpp"
38 #include "gc/shared/oopStorage.hpp"
39 #include "gc/shared/oopStorageSet.hpp"
40 #include "gc/shared/tlab_globals.hpp"
41 #include "jfr/jfrEvents.hpp"
42 #include "jvm.h"
43 #include "jvmtifiles/jvmtiEnv.hpp"
44 #include "logging/log.hpp"
45 #include "logging/logAsyncWriter.hpp"
46 #include "logging/logStream.hpp"
47 #include "memory/allocation.inline.hpp"
48 #include "memory/iterator.hpp"
49 #include "memory/universe.hpp"
50 #include "oops/access.inline.hpp"
51 #include "oops/instanceKlass.hpp"
52 #include "oops/klass.inline.hpp"
53 #include "oops/oop.inline.hpp"
54 #include "oops/oopHandle.inline.hpp"
55 #include "oops/verifyOopClosure.hpp"
56 #include "prims/jvm_misc.hpp"
57 #include "prims/jvmtiDeferredUpdates.hpp"
58 #include "prims/jvmtiExport.hpp"
59 #include "prims/jvmtiThreadState.inline.hpp"
60 #include "runtime/atomic.hpp"
61 #include "runtime/continuation.hpp"
62 #include "runtime/continuationEntry.inline.hpp"
63 #include "runtime/continuationHelper.inline.hpp"
64 #include "runtime/deoptimization.hpp"
65 #include "runtime/frame.inline.hpp"
66 #include "runtime/handles.inline.hpp"
67 #include "runtime/handshake.hpp"
68 #include "runtime/interfaceSupport.inline.hpp"
69 #include "runtime/java.hpp"
70 #include "runtime/javaCalls.hpp"
71 #include "runtime/javaThread.inline.hpp"
72 #include "runtime/jniHandles.inline.hpp"
73 #include "runtime/lockStack.inline.hpp"
74 #include "runtime/mutexLocker.hpp"
75 #include "runtime/orderAccess.hpp"
76 #include "runtime/os.inline.hpp"
77 #include "runtime/osThread.hpp"
78 #include "runtime/safepoint.hpp"
79 #include "runtime/safepointMechanism.inline.hpp"
80 #include "runtime/safepointVerifiers.hpp"
81 #include "runtime/serviceThread.hpp"
82 #include "runtime/stackFrameStream.inline.hpp"
83 #include "runtime/stackWatermarkSet.hpp"
84 #include "runtime/synchronizer.hpp"
85 #include "runtime/threadCritical.hpp"
86 #include "runtime/threadIdentifier.hpp"
87 #include "runtime/threadSMR.inline.hpp"
88 #include "runtime/threadStatisticalInfo.hpp"
89 #include "runtime/threadWXSetters.inline.hpp"
90 #include "runtime/timer.hpp"
91 #include "runtime/timerTrace.hpp"
92 #include "runtime/vframe.inline.hpp"
93 #include "runtime/vframeArray.hpp"
94 #include "runtime/vframe_hp.hpp"
95 #include "runtime/vmThread.hpp"
96 #include "runtime/vmOperations.hpp"
97 #include "services/threadService.hpp"
98 #include "utilities/copy.hpp"
99 #include "utilities/defaultStream.hpp"
100 #include "utilities/dtrace.hpp"
101 #include "utilities/events.hpp"
102 #include "utilities/macros.hpp"
103 #include "utilities/nativeStackPrinter.hpp"
104 #include "utilities/preserveException.hpp"
105 #include "utilities/spinYield.hpp"
106 #include "utilities/vmError.hpp"
107 #if INCLUDE_JVMCI
108 #include "jvmci/jvmci.hpp"
109 #include "jvmci/jvmciEnv.hpp"
110 #endif
111 #if INCLUDE_JFR
112 #include "jfr/jfr.hpp"
113 #endif
114
115 // Set by os layer.
116 size_t JavaThread::_stack_size_at_create = 0;
117
118 #ifdef DTRACE_ENABLED
119
120 // Only bother with this argument setup if dtrace is available
121
122 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
123 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
124
125 #define DTRACE_THREAD_PROBE(probe, javathread) \
126 { \
127 ResourceMark rm(this); \
128 int len = 0; \
129 const char* name = (javathread)->name(); \
130 len = strlen(name); \
131 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
132 (char *) name, len, \
133 java_lang_Thread::thread_id((javathread)->threadObj()), \
134 (uintptr_t) (javathread)->osthread()->thread_id(), \
135 java_lang_Thread::is_daemon((javathread)->threadObj())); \
136 }
137
138 #else // ndef DTRACE_ENABLED
139
140 #define DTRACE_THREAD_PROBE(probe, javathread)
141
142 #endif // ndef DTRACE_ENABLED
143
144 void JavaThread::smr_delete() {
145 if (_on_thread_list) {
146 ThreadsSMRSupport::smr_delete(this);
147 } else {
148 delete this;
149 }
150 }
151
152 // Initialized by VMThread at vm_global_init
153 OopStorage* JavaThread::_thread_oop_storage = nullptr;
154
155 OopStorage* JavaThread::thread_oop_storage() {
156 assert(_thread_oop_storage != nullptr, "not yet initialized");
157 return _thread_oop_storage;
158 }
159
160 void JavaThread::set_threadOopHandles(oop p) {
161 assert(_thread_oop_storage != nullptr, "not yet initialized");
162 _threadObj = OopHandle(_thread_oop_storage, p);
163 _vthread = OopHandle(_thread_oop_storage, p);
164 _jvmti_vthread = OopHandle(_thread_oop_storage, p->is_a(vmClasses::BoundVirtualThread_klass()) ? p : nullptr);
165 _scopedValueCache = OopHandle(_thread_oop_storage, nullptr);
166 }
167
168 oop JavaThread::threadObj() const {
169 // Ideally we would verify the current thread is oop_safe when this is called, but as we can
170 // be called from a signal handler we would have to use Thread::current_or_null_safe(). That
171 // has overhead and also interacts poorly with GetLastError on Windows due to the use of TLS.
172 // Instead callers must verify oop safe access.
173 return _threadObj.resolve();
174 }
175
176 oop JavaThread::vthread() const {
177 return _vthread.resolve();
178 }
179
180 void JavaThread::set_vthread(oop p) {
181 assert(_thread_oop_storage != nullptr, "not yet initialized");
182 _vthread.replace(p);
183 }
184
185 oop JavaThread::jvmti_vthread() const {
186 return _jvmti_vthread.resolve();
187 }
188
189 void JavaThread::set_jvmti_vthread(oop p) {
190 assert(_thread_oop_storage != nullptr, "not yet initialized");
191 _jvmti_vthread.replace(p);
192 }
193
194 // If there is a virtual thread mounted then return vthread() oop.
195 // Otherwise, return threadObj().
196 oop JavaThread::vthread_or_thread() const {
197 oop result = vthread();
198 if (result == nullptr) {
199 result = threadObj();
200 }
201 return result;
202 }
203
204 oop JavaThread::scopedValueCache() const {
205 return _scopedValueCache.resolve();
206 }
207
208 void JavaThread::set_scopedValueCache(oop p) {
209 if (!_scopedValueCache.is_empty()) { // i.e. if the OopHandle has been allocated
210 _scopedValueCache.replace(p);
211 } else {
212 assert(p == nullptr, "not yet initialized");
213 }
214 }
215
216 void JavaThread::clear_scopedValueBindings() {
217 set_scopedValueCache(nullptr);
218 oop vthread_oop = vthread();
219 // vthread may be null here if we get a VM error during startup,
220 // before the java.lang.Thread instance has been created.
221 if (vthread_oop != nullptr) {
222 java_lang_Thread::clear_scopedValueBindings(vthread_oop);
223 }
224 }
225
226 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
227 bool daemon, TRAPS) {
228 assert(thread_group.not_null(), "thread group should be specified");
229 assert(threadObj() == nullptr, "should only create Java thread object once");
230
231 InstanceKlass* ik = vmClasses::Thread_klass();
232 assert(ik->is_initialized(), "must be");
233 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
234
235 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
236 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
237 // constructor calls Thread.current(), which must be set here.
238 java_lang_Thread::set_thread(thread_oop(), this);
239 set_threadOopHandles(thread_oop());
240 // Set the _monitor_owner_id to the next thread_id temporarily while initialization runs.
241 set_monitor_owner_id(ThreadIdentifier::next());
242
243 JavaValue result(T_VOID);
244 if (thread_name != nullptr) {
245 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
246 // Thread gets assigned specified name and null target
247 JavaCalls::call_special(&result,
248 thread_oop,
249 ik,
250 vmSymbols::object_initializer_name(),
251 vmSymbols::threadgroup_string_void_signature(),
252 thread_group,
253 name,
254 CHECK);
255 } else {
256 // Thread gets assigned name "Thread-nnn" and null target
257 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
258 JavaCalls::call_special(&result,
259 thread_oop,
260 ik,
261 vmSymbols::object_initializer_name(),
262 vmSymbols::threadgroup_runnable_void_signature(),
263 thread_group,
264 Handle(),
265 CHECK);
266 }
267 // Update the _monitor_owner_id with the tid value.
268 set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
269
270 os::set_priority(this, NormPriority);
271
272 if (daemon) {
273 java_lang_Thread::set_daemon(thread_oop());
274 }
275 }
276
277 // ======= JavaThread ========
278
279 #if INCLUDE_JVMCI
280
281 jlong* JavaThread::_jvmci_old_thread_counters;
282
283 static bool jvmci_counters_include(JavaThread* thread) {
284 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
285 }
286
287 void JavaThread::collect_counters(jlong* array, int length) {
288 assert(length == JVMCICounterSize, "wrong value");
289 for (int i = 0; i < length; i++) {
290 array[i] = _jvmci_old_thread_counters[i];
291 }
292 for (JavaThread* tp : ThreadsListHandle()) {
293 if (jvmci_counters_include(tp)) {
294 for (int i = 0; i < length; i++) {
295 array[i] += tp->_jvmci_counters[i];
296 }
297 }
298 }
299 }
300
301 // Attempt to enlarge the array for per thread counters.
302 static jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
303 jlong* new_counters = NEW_C_HEAP_ARRAY_RETURN_NULL(jlong, new_size, mtJVMCI);
304 if (new_counters == nullptr) {
305 return nullptr;
306 }
307 if (old_counters == nullptr) {
308 old_counters = new_counters;
309 memset(old_counters, 0, sizeof(jlong) * new_size);
310 } else {
311 for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
312 new_counters[i] = old_counters[i];
313 }
314 if (new_size > current_size) {
315 memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
316 }
317 FREE_C_HEAP_ARRAY(jlong, old_counters);
318 }
319 return new_counters;
320 }
321
322 // Attempt to enlarge the array for per thread counters.
323 bool JavaThread::resize_counters(int current_size, int new_size) {
324 jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
325 if (new_counters == nullptr) {
326 return false;
327 } else {
328 _jvmci_counters = new_counters;
329 return true;
330 }
331 }
332
333 class VM_JVMCIResizeCounters : public VM_Operation {
334 private:
335 int _new_size;
336 bool _failed;
337
338 public:
339 VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { }
340 VMOp_Type type() const { return VMOp_JVMCIResizeCounters; }
341 bool allow_nested_vm_operations() const { return true; }
342 void doit() {
343 // Resize the old thread counters array
344 jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
345 if (new_counters == nullptr) {
346 _failed = true;
347 return;
348 } else {
349 JavaThread::_jvmci_old_thread_counters = new_counters;
350 }
351
352 // Now resize each threads array
353 for (JavaThread* tp : ThreadsListHandle()) {
354 if (!tp->resize_counters(JVMCICounterSize, _new_size)) {
355 _failed = true;
356 break;
357 }
358 }
359 if (!_failed) {
360 JVMCICounterSize = _new_size;
361 }
362 }
363
364 bool failed() { return _failed; }
365 };
366
367 bool JavaThread::resize_all_jvmci_counters(int new_size) {
368 VM_JVMCIResizeCounters op(new_size);
369 VMThread::execute(&op);
370 return !op.failed();
371 }
372
373 #endif // INCLUDE_JVMCI
374
375 #ifdef ASSERT
376 // Checks safepoint allowed and clears unhandled oops at potential safepoints.
377 void JavaThread::check_possible_safepoint() {
378 if (_no_safepoint_count > 0) {
379 print_owned_locks();
380 assert(false, "Possible safepoint reached by thread that does not allow it");
381 }
382 #ifdef CHECK_UNHANDLED_OOPS
383 // Clear unhandled oops in JavaThreads so we get a crash right away.
384 clear_unhandled_oops();
385 #endif // CHECK_UNHANDLED_OOPS
386
387 // Macos/aarch64 should be in the right state for safepoint (e.g.
388 // deoptimization needs WXWrite). Crashes caused by the wrong state rarely
389 // happens in practice, making such issues hard to find and reproduce.
390 #if defined(__APPLE__) && defined(AARCH64)
391 if (AssertWXAtThreadSync) {
392 assert_wx_state(WXWrite);
393 }
394 #endif
395 }
396
397 void JavaThread::check_for_valid_safepoint_state() {
398 // Don't complain if running a debugging command.
399 if (DebuggingContext::is_enabled()) return;
400
401 // Check NoSafepointVerifier, which is implied by locks taken that can be
402 // shared with the VM thread. This makes sure that no locks with allow_vm_block
403 // are held.
404 check_possible_safepoint();
405
406 if (thread_state() != _thread_in_vm) {
407 fatal("LEAF method calling lock?");
408 }
409
410 if (GCALotAtAllSafepoints) {
411 // We could enter a safepoint here and thus have a gc
412 InterfaceSupport::check_gc_alot();
413 }
414 }
415 #endif // ASSERT
416
417 // A JavaThread is a normal Java thread
418
419 JavaThread::JavaThread(MemTag mem_tag) :
420 Thread(mem_tag),
421 // Initialize fields
422 _on_thread_list(false),
423 DEBUG_ONLY(_java_call_counter(0) COMMA)
424 _entry_point(nullptr),
425 _deopt_mark(nullptr),
426 _deopt_nmethod(nullptr),
427 _vframe_array_head(nullptr),
428 _vframe_array_last(nullptr),
429 _jvmti_deferred_updates(nullptr),
430 _callee_target(nullptr),
431 _vm_result(nullptr),
432 _vm_result_2(nullptr),
433
434 _current_pending_monitor(nullptr),
435 _current_pending_monitor_is_from_java(true),
436 _current_waiting_monitor(nullptr),
437 _active_handles(nullptr),
438 _free_handle_block(nullptr),
439 _monitor_owner_id(0),
440
441 _suspend_flags(0),
442
443 _thread_state(_thread_new),
444 _saved_exception_pc(nullptr),
445 #ifdef ASSERT
446 _no_safepoint_count(0),
447 _visited_for_critical_count(false),
448 #endif
449
450 _terminated(_not_terminated),
451 _in_deopt_handler(0),
452 _doing_unsafe_access(false),
453 _do_not_unlock_if_synchronized(false),
454 #if INCLUDE_JVMTI
455 _carrier_thread_suspended(false),
456 _is_in_VTMS_transition(false),
457 _is_disable_suspend(false),
458 _VTMS_transition_mark(false),
459 _on_monitor_waited_event(false),
460 _contended_entered_monitor(nullptr),
461 #ifdef ASSERT
462 _is_VTMS_transition_disabler(false),
463 #endif
464 #endif
465 _jni_attach_state(_not_attaching_via_jni),
466 _is_in_internal_oome_mark(false),
467 #if INCLUDE_JVMCI
468 _pending_deoptimization(-1),
469 _pending_monitorenter(false),
470 _pending_transfer_to_interpreter(false),
471 _pending_failed_speculation(0),
472 _jvmci{nullptr},
473 _libjvmci_runtime(nullptr),
474 _jvmci_counters(nullptr),
475 _jvmci_reserved0(0),
476 _jvmci_reserved1(0),
477 _jvmci_reserved_oop0(nullptr),
478 _live_nmethod(nullptr),
479 #endif // INCLUDE_JVMCI
480
481 _exception_oop(oop()),
482 _exception_pc(nullptr),
483 _exception_handler_pc(nullptr),
484 _is_method_handle_return(0),
485
486 _jni_active_critical(0),
487 _pending_jni_exception_check_fn(nullptr),
488 _depth_first_number(0),
489
490 // JVMTI PopFrame support
491 _popframe_condition(popframe_inactive),
492 _frames_to_pop_failed_realloc(0),
493
494 _cont_entry(nullptr),
495 _cont_fastpath(nullptr),
496 _cont_fastpath_thread_state(1),
497 _held_monitor_count(0),
498 _jni_monitor_count(0),
499 _unlocked_inflated_monitor(nullptr),
500
501 _preempt_alternate_return(nullptr),
502 _preemption_cancelled(false),
503 _pending_interrupted_exception(false),
504
505 _handshake(this),
506
507 _popframe_preserved_args(nullptr),
508 _popframe_preserved_args_size(0),
509
510 _jvmti_thread_state(nullptr),
511 _interp_only_mode(0),
512 _should_post_on_exceptions_flag(JNI_FALSE),
513 _thread_stat(new ThreadStatistics()),
514
515 _parker(),
516
517 _class_to_be_initialized(nullptr),
518 _class_being_initialized(nullptr),
519
520 _SleepEvent(ParkEvent::Allocate(this)),
521
522 #if INCLUDE_JFR
523 _last_freeze_fail_result(freeze_ok),
524 #endif
525
526 _lock_stack(this),
527 _om_cache(this) {
528 set_jni_functions(jni_functions());
529
530 #if INCLUDE_JVMCI
531 assert(_jvmci._implicit_exception_pc == nullptr, "must be");
532 if (JVMCICounterSize > 0) {
533 resize_counters(0, (int) JVMCICounterSize);
534 }
535 #endif // INCLUDE_JVMCI
536
537 // Setup safepoint state info for this thread
538 ThreadSafepointState::create(this);
539
540 SafepointMechanism::initialize_header(this);
541
542 set_requires_cross_modify_fence(false);
543
544 pd_initialize();
545 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
546 }
547
548 JavaThread* JavaThread::create_attaching_thread() {
549 JavaThread* jt = new JavaThread();
550 jt->_jni_attach_state = _attaching_via_jni;
551 return jt;
552 }
553
554 // interrupt support
555
556 void JavaThread::interrupt() {
557 // All callers should have 'this' thread protected by a
558 // ThreadsListHandle so that it cannot terminate and deallocate
559 // itself.
560 debug_only(check_for_dangling_thread_pointer(this);)
561
562 // For Windows _interrupt_event
563 WINDOWS_ONLY(osthread()->set_interrupted(true);)
564
565 // For Thread.sleep
566 _SleepEvent->unpark();
567
568 // For JSR166 LockSupport.park
569 parker()->unpark();
570
571 // For ObjectMonitor and JvmtiRawMonitor
572 _ParkEvent->unpark();
573 }
574
575 bool JavaThread::is_interrupted(bool clear_interrupted) {
576 debug_only(check_for_dangling_thread_pointer(this);)
577
578 if (_threadObj.peek() == nullptr) {
579 // If there is no j.l.Thread then it is impossible to have
580 // been interrupted. We can find null during VM initialization
581 // or when a JNI thread is still in the process of attaching.
582 // In such cases this must be the current thread.
583 assert(this == Thread::current(), "invariant");
584 return false;
585 }
586
587 bool interrupted = java_lang_Thread::interrupted(threadObj());
588
589 // NOTE that since there is no "lock" around the interrupt and
590 // is_interrupted operations, there is the possibility that the
591 // interrupted flag will be "false" but that the
592 // low-level events will be in the signaled state. This is
593 // intentional. The effect of this is that Object.wait() and
594 // LockSupport.park() will appear to have a spurious wakeup, which
595 // is allowed and not harmful, and the possibility is so rare that
596 // it is not worth the added complexity to add yet another lock.
597 // For the sleep event an explicit reset is performed on entry
598 // to JavaThread::sleep, so there is no early return. It has also been
599 // recommended not to put the interrupted flag into the "event"
600 // structure because it hides the issue.
601 // Also, because there is no lock, we must only clear the interrupt
602 // state if we are going to report that we were interrupted; otherwise
603 // an interrupt that happens just after we read the field would be lost.
604 if (interrupted && clear_interrupted) {
605 assert(this == Thread::current(), "only the current thread can clear");
606 java_lang_Thread::set_interrupted(threadObj(), false);
607 WINDOWS_ONLY(osthread()->set_interrupted(false);)
608 }
609 return interrupted;
610 }
611
612 // This is only for use by JVMTI RawMonitorWait. It emulates the actions of
613 // the Java code in Object::wait which are not present in RawMonitorWait.
614 bool JavaThread::get_and_clear_interrupted() {
615 if (!is_interrupted(false)) {
616 return false;
617 }
618 oop thread_oop = vthread_or_thread();
619 bool is_virtual = java_lang_VirtualThread::is_instance(thread_oop);
620
621 if (!is_virtual) {
622 return is_interrupted(true);
623 }
624 // Virtual thread: clear interrupt status for both virtual and
625 // carrier threads under the interruptLock protection.
626 JavaThread* current = JavaThread::current();
627 HandleMark hm(current);
628 Handle thread_h(current, thread_oop);
629 ObjectLocker lock(Handle(current, java_lang_Thread::interrupt_lock(thread_h())), current);
630
631 // re-check the interrupt status under the interruptLock protection
632 bool interrupted = java_lang_Thread::interrupted(thread_h());
633
634 if (interrupted) {
635 assert(this == Thread::current(), "only the current thread can clear");
636 java_lang_Thread::set_interrupted(thread_h(), false); // clear for virtual
637 java_lang_Thread::set_interrupted(threadObj(), false); // clear for carrier
638 WINDOWS_ONLY(osthread()->set_interrupted(false);)
639 }
640 return interrupted;
641 }
642
643 void JavaThread::block_if_vm_exited() {
644 if (_terminated == _vm_exited) {
645 // _vm_exited is set at safepoint, and Threads_lock is never released
646 // so we will block here forever.
647 // Here we can be doing a jump from a safe state to an unsafe state without
648 // proper transition, but it happens after the final safepoint has begun so
649 // this jump won't cause any safepoint problems.
650 set_thread_state(_thread_in_vm);
651 Threads_lock->lock();
652 ShouldNotReachHere();
653 }
654 }
655
656 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz, MemTag mem_tag) : JavaThread(mem_tag) {
657 set_entry_point(entry_point);
658 // Create the native thread itself.
659 // %note runtime_23
660 os::ThreadType thr_type = os::java_thread;
661 thr_type = entry_point == &CompilerThread::thread_entry ? os::compiler_thread :
662 os::java_thread;
663 os::create_thread(this, thr_type, stack_sz);
664 // The _osthread may be null here because we ran out of memory (too many threads active).
665 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
666 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
667 // the exception consists of creating the exception object & initializing it, initialization
668 // will leave the VM via a JavaCall and then all locks must be unlocked).
669 //
670 // The thread is still suspended when we reach here. Thread must be explicit started
671 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
672 // by calling Threads:add. The reason why this is not done here, is because the thread
673 // object must be fully initialized (take a look at JVM_Start)
674 }
675
676 JavaThread::~JavaThread() {
677
678 // Enqueue OopHandles for release by the service thread.
679 add_oop_handles_for_release();
680
681 // Return the sleep event to the free list
682 ParkEvent::Release(_SleepEvent);
683 _SleepEvent = nullptr;
684
685 // Free any remaining previous UnrollBlock
686 vframeArray* old_array = vframe_array_last();
687
688 if (old_array != nullptr) {
689 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
690 old_array->set_unroll_block(nullptr);
691 delete old_info;
692 delete old_array;
693 }
694
695 JvmtiDeferredUpdates* updates = deferred_updates();
696 if (updates != nullptr) {
697 // This can only happen if thread is destroyed before deoptimization occurs.
698 assert(updates->count() > 0, "Updates holder not deleted");
699 // free deferred updates.
700 delete updates;
701 set_deferred_updates(nullptr);
702 }
703
704 // All Java related clean up happens in exit
705 ThreadSafepointState::destroy(this);
706 if (_thread_stat != nullptr) delete _thread_stat;
707
708 #if INCLUDE_JVMCI
709 if (JVMCICounterSize > 0) {
710 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
711 }
712 #endif // INCLUDE_JVMCI
713 }
714
715
716 // First JavaThread specific code executed by a new Java thread.
717 void JavaThread::pre_run() {
718 // empty - see comments in run()
719 }
720
721 // The main routine called by a new Java thread. This isn't overridden
722 // by subclasses, instead different subclasses define a different "entry_point"
723 // which defines the actual logic for that kind of thread.
724 void JavaThread::run() {
725 // initialize thread-local alloc buffer related fields
726 initialize_tlab();
727
728 _stack_overflow_state.create_stack_guard_pages();
729
730 cache_global_variables();
731
732 // Thread is now sufficiently initialized to be handled by the safepoint code as being
733 // in the VM. Change thread state from _thread_new to _thread_in_vm
734 assert(this->thread_state() == _thread_new, "wrong thread state");
735 set_thread_state(_thread_in_vm);
736
737 // Before a thread is on the threads list it is always safe, so after leaving the
738 // _thread_new we should emit a instruction barrier. The distance to modified code
739 // from here is probably far enough, but this is consistent and safe.
740 OrderAccess::cross_modify_fence();
741
742 assert(JavaThread::current() == this, "sanity check");
743 assert(!Thread::current()->owns_locks(), "sanity check");
744
745 DTRACE_THREAD_PROBE(start, this);
746
747 // This operation might block. We call that after all safepoint checks for a new thread has
748 // been completed.
749 set_active_handles(JNIHandleBlock::allocate_block());
750
751 if (JvmtiExport::should_post_thread_life()) {
752 JvmtiExport::post_thread_start(this);
753
754 }
755
756 if (AlwaysPreTouchStacks) {
757 pretouch_stack();
758 }
759
760 // We call another function to do the rest so we are sure that the stack addresses used
761 // from there will be lower than the stack base just computed.
762 thread_main_inner();
763 }
764
765 void JavaThread::thread_main_inner() {
766 assert(JavaThread::current() == this, "sanity check");
767 assert(_threadObj.peek() != nullptr, "just checking");
768
769 // Execute thread entry point unless this thread has a pending exception.
770 // Note: Due to JVMTI StopThread we can have pending exceptions already!
771 if (!this->has_pending_exception()) {
772 {
773 ResourceMark rm(this);
774 this->set_native_thread_name(this->name());
775 }
776 HandleMark hm(this);
777 this->entry_point()(this, this);
778 }
779
780 DTRACE_THREAD_PROBE(stop, this);
781
782 // Cleanup is handled in post_run()
783 }
784
785 // Shared teardown for all JavaThreads
786 void JavaThread::post_run() {
787 this->exit(false);
788 this->unregister_thread_stack_with_NMT();
789 // Defer deletion to here to ensure 'this' is still referenceable in call_run
790 // for any shared tear-down.
791 this->smr_delete();
792 }
793
794 static void ensure_join(JavaThread* thread) {
795 // We do not need to grab the Threads_lock, since we are operating on ourself.
796 Handle threadObj(thread, thread->threadObj());
797 assert(threadObj.not_null(), "java thread object must exist");
798 ObjectLocker lock(threadObj, thread);
799 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
800 java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED);
801 // Clear the native thread instance - this makes isAlive return false and allows the join()
802 // to complete once we've done the notify_all below. Needs a release() to obey Java Memory Model
803 // requirements.
804 assert(java_lang_Thread::thread(threadObj()) == thread, "must be alive");
805 java_lang_Thread::release_set_thread(threadObj(), nullptr);
806 lock.notify_all(thread);
807 // Ignore pending exception, since we are exiting anyway
808 thread->clear_pending_exception();
809 }
810
811 static bool is_daemon(oop threadObj) {
812 return (threadObj != nullptr && java_lang_Thread::is_daemon(threadObj));
813 }
814
815 // For any new cleanup additions, please check to see if they need to be applied to
816 // cleanup_failed_attach_current_thread as well.
817 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
818 assert(this == JavaThread::current(), "thread consistency check");
819 assert(!is_exiting(), "should not be exiting or terminated already");
820
821 elapsedTimer _timer_exit_phase1;
822 elapsedTimer _timer_exit_phase2;
823 elapsedTimer _timer_exit_phase3;
824 elapsedTimer _timer_exit_phase4;
825
826 om_clear_monitor_cache();
827
828 if (log_is_enabled(Debug, os, thread, timer)) {
829 _timer_exit_phase1.start();
830 }
831
832 HandleMark hm(this);
833 Handle uncaught_exception(this, this->pending_exception());
834 this->clear_pending_exception();
835 Handle threadObj(this, this->threadObj());
836 assert(threadObj.not_null(), "Java thread object should be created");
837
838 if (!destroy_vm) {
839 if (uncaught_exception.not_null()) {
840 EXCEPTION_MARK;
841 // Call method Thread.dispatchUncaughtException().
842 Klass* thread_klass = vmClasses::Thread_klass();
843 JavaValue result(T_VOID);
844 JavaCalls::call_virtual(&result,
845 threadObj, thread_klass,
846 vmSymbols::dispatchUncaughtException_name(),
847 vmSymbols::throwable_void_signature(),
848 uncaught_exception,
849 THREAD);
850 if (HAS_PENDING_EXCEPTION) {
851 ResourceMark rm(this);
852 jio_fprintf(defaultStream::error_stream(),
853 "\nException: %s thrown from the UncaughtExceptionHandler"
854 " in thread \"%s\"\n",
855 pending_exception()->klass()->external_name(),
856 name());
857 CLEAR_PENDING_EXCEPTION;
858 }
859 }
860
861 if (!is_Compiler_thread()) {
862 // We have finished executing user-defined Java code and now have to do the
863 // implementation specific clean-up by calling Thread.exit(). We prevent any
864 // asynchronous exceptions from being delivered while in Thread.exit()
865 // to ensure the clean-up is not corrupted.
866 NoAsyncExceptionDeliveryMark _no_async(this);
867
868 EXCEPTION_MARK;
869 JavaValue result(T_VOID);
870 Klass* thread_klass = vmClasses::Thread_klass();
871 JavaCalls::call_virtual(&result,
872 threadObj, thread_klass,
873 vmSymbols::exit_method_name(),
874 vmSymbols::void_method_signature(),
875 THREAD);
876 CLEAR_PENDING_EXCEPTION;
877 }
878
879 // notify JVMTI
880 if (JvmtiExport::should_post_thread_life()) {
881 JvmtiExport::post_thread_end(this);
882 }
883 } else {
884 // before_exit() has already posted JVMTI THREAD_END events
885 }
886
887 // Cleanup any pending async exception now since we cannot access oops after
888 // BarrierSet::barrier_set()->on_thread_detach() has been executed.
889 if (has_async_exception_condition()) {
890 handshake_state()->clean_async_exception_operation();
891 }
892
893 // The careful dance between thread suspension and exit is handled here.
894 // Since we are in thread_in_vm state and suspension is done with handshakes,
895 // we can just put in the exiting state and it will be correctly handled.
896 // Also, no more async exceptions will be added to the queue after this point.
897 set_terminated(_thread_exiting);
898 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
899
900 if (log_is_enabled(Debug, os, thread, timer)) {
901 _timer_exit_phase1.stop();
902 _timer_exit_phase2.start();
903 }
904
905 // Capture daemon status before the thread is marked as terminated.
906 bool daemon = is_daemon(threadObj());
907
908 // Notify waiters on thread object. This has to be done after exit() is called
909 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
910 // group should have the destroyed bit set before waiters are notified).
911 ensure_join(this);
912 assert(!this->has_pending_exception(), "ensure_join should have cleared");
913
914 if (log_is_enabled(Debug, os, thread, timer)) {
915 _timer_exit_phase2.stop();
916 _timer_exit_phase3.start();
917 }
918 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
919 // held by this thread must be released. The spec does not distinguish
920 // between JNI-acquired and regular Java monitors. We can only see
921 // regular Java monitors here if monitor enter-exit matching is broken.
922 //
923 // ensure_join() ignores IllegalThreadStateExceptions, and so does
924 // ObjectSynchronizer::release_monitors_owned_by_thread().
925 if (exit_type == jni_detach) {
926 // Sanity check even though JNI DetachCurrentThread() would have
927 // returned JNI_ERR if there was a Java frame. JavaThread exit
928 // should be done executing Java code by the time we get here.
929 assert(!this->has_last_Java_frame(),
930 "should not have a Java frame when detaching or exiting");
931 ObjectSynchronizer::release_monitors_owned_by_thread(this);
932 assert(!this->has_pending_exception(), "release_monitors should have cleared");
933 // Check for monitor counts being out of sync.
934 assert(held_monitor_count() == jni_monitor_count(),
935 "held monitor count should be equal to jni: %zd != %zd",
936 held_monitor_count(), jni_monitor_count());
937 // All in-use monitors, including JNI-locked ones, should have been released above.
938 assert(held_monitor_count() == 0, "Failed to unlock %zd object monitors",
939 held_monitor_count());
940 } else {
941 // Check for monitor counts being out of sync.
942 assert(held_monitor_count() == jni_monitor_count(),
943 "held monitor count should be equal to jni: %zd != %zd",
944 held_monitor_count(), jni_monitor_count());
945 // It is possible that a terminating thread failed to unlock monitors it locked
946 // via JNI so we don't assert the count is zero.
947 }
948
949 if (CheckJNICalls && jni_monitor_count() > 0) {
950 // We would like a fatal here, but due to we never checked this before there
951 // is a lot of tests which breaks, even with an error log.
952 log_debug(jni)("JavaThread %s (tid: %zu) with Objects still locked by JNI MonitorEnter.",
953 exit_type == JavaThread::normal_exit ? "exiting" : "detaching", os::current_thread_id());
954 }
955
956 // These things needs to be done while we are still a Java Thread. Make sure that thread
957 // is in a consistent state, in case GC happens
958 JFR_ONLY(Jfr::on_thread_exit(this);)
959
960 if (active_handles() != nullptr) {
961 JNIHandleBlock* block = active_handles();
962 set_active_handles(nullptr);
963 JNIHandleBlock::release_block(block);
964 }
965
966 if (free_handle_block() != nullptr) {
967 JNIHandleBlock* block = free_handle_block();
968 set_free_handle_block(nullptr);
969 JNIHandleBlock::release_block(block);
970 }
971
972 // These have to be removed while this is still a valid thread.
973 _stack_overflow_state.remove_stack_guard_pages();
974
975 if (UseTLAB) {
976 tlab().retire();
977 }
978
979 if (JvmtiEnv::environments_might_exist()) {
980 JvmtiExport::cleanup_thread(this);
981 }
982
983 // We need to cache the thread name for logging purposes below as once
984 // we have called on_thread_detach this thread must not access any oops.
985 char* thread_name = nullptr;
986 if (log_is_enabled(Debug, os, thread, timer)) {
987 ResourceMark rm(this);
988 thread_name = os::strdup(name());
989 }
990
991 if (log_is_enabled(Info, os, thread)) {
992 ResourceMark rm(this);
993 log_info(os, thread)("JavaThread %s (name: \"%s\", tid: %zu).",
994 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
995 name(), os::current_thread_id());
996 }
997
998 if (log_is_enabled(Debug, os, thread, timer)) {
999 _timer_exit_phase3.stop();
1000 _timer_exit_phase4.start();
1001 }
1002
1003 #if INCLUDE_JVMCI
1004 if (JVMCICounterSize > 0) {
1005 if (jvmci_counters_include(this)) {
1006 for (int i = 0; i < JVMCICounterSize; i++) {
1007 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1008 }
1009 }
1010 }
1011 #endif // INCLUDE_JVMCI
1012
1013 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread.
1014 // We call BarrierSet::barrier_set()->on_thread_detach() here so no touching of oops after this point.
1015 Threads::remove(this, daemon);
1016
1017 if (log_is_enabled(Debug, os, thread, timer)) {
1018 _timer_exit_phase4.stop();
1019 log_debug(os, thread, timer)("name='%s'"
1020 ", exit-phase1=" JLONG_FORMAT
1021 ", exit-phase2=" JLONG_FORMAT
1022 ", exit-phase3=" JLONG_FORMAT
1023 ", exit-phase4=" JLONG_FORMAT,
1024 thread_name,
1025 _timer_exit_phase1.milliseconds(),
1026 _timer_exit_phase2.milliseconds(),
1027 _timer_exit_phase3.milliseconds(),
1028 _timer_exit_phase4.milliseconds());
1029 os::free(thread_name);
1030 }
1031 }
1032
1033 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
1034 if (active_handles() != nullptr) {
1035 JNIHandleBlock* block = active_handles();
1036 set_active_handles(nullptr);
1037 JNIHandleBlock::release_block(block);
1038 }
1039
1040 if (free_handle_block() != nullptr) {
1041 JNIHandleBlock* block = free_handle_block();
1042 set_free_handle_block(nullptr);
1043 JNIHandleBlock::release_block(block);
1044 }
1045
1046 // These have to be removed while this is still a valid thread.
1047 _stack_overflow_state.remove_stack_guard_pages();
1048
1049 if (UseTLAB) {
1050 tlab().retire();
1051 }
1052
1053 Threads::remove(this, is_daemon);
1054 }
1055
1056 JavaThread* JavaThread::active() {
1057 Thread* thread = Thread::current();
1058 if (thread->is_Java_thread()) {
1059 return JavaThread::cast(thread);
1060 } else {
1061 assert(thread->is_VM_thread(), "this must be a vm thread");
1062 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1063 JavaThread *ret = op == nullptr ? nullptr : JavaThread::cast(op->calling_thread());
1064 return ret;
1065 }
1066 }
1067
1068 bool JavaThread::is_lock_owned(address adr) const {
1069 assert(LockingMode != LM_LIGHTWEIGHT, "should not be called with new lightweight locking");
1070 return is_in_full_stack(adr);
1071 }
1072
1073 oop JavaThread::exception_oop() const {
1074 return Atomic::load(&_exception_oop);
1075 }
1076
1077 void JavaThread::set_exception_oop(oop o) {
1078 Atomic::store(&_exception_oop, o);
1079 }
1080
1081 void JavaThread::handle_special_runtime_exit_condition() {
1082 if (is_obj_deopt_suspend()) {
1083 frame_anchor()->make_walkable();
1084 wait_for_object_deoptimization();
1085 }
1086 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
1087 }
1088
1089
1090 // Asynchronous exceptions support
1091 //
1092 void JavaThread::handle_async_exception(oop java_throwable) {
1093 assert(java_throwable != nullptr, "should have an _async_exception to throw");
1094 assert(!is_at_poll_safepoint(), "should have never called this method");
1095
1096 if (has_last_Java_frame()) {
1097 frame f = last_frame();
1098 if (f.is_runtime_frame()) {
1099 // If the topmost frame is a runtime stub, then we are calling into
1100 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1101 // must deoptimize the caller before continuing, as the compiled exception
1102 // handler table may not be valid.
1103 RegisterMap reg_map(this,
1104 RegisterMap::UpdateMap::skip,
1105 RegisterMap::ProcessFrames::include,
1106 RegisterMap::WalkContinuation::skip);
1107 frame compiled_frame = f.sender(®_map);
1108 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1109 Deoptimization::deoptimize(this, compiled_frame);
1110 }
1111 }
1112 }
1113
1114 // We cannot call Exceptions::_throw(...) here because we cannot block
1115 set_pending_exception(java_throwable, __FILE__, __LINE__);
1116
1117 clear_scopedValueBindings();
1118
1119 LogTarget(Info, exceptions) lt;
1120 if (lt.is_enabled()) {
1121 ResourceMark rm;
1122 LogStream ls(lt);
1123 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1124 if (has_last_Java_frame()) {
1125 frame f = last_frame();
1126 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1127 }
1128 ls.print_cr(" of type: %s", java_throwable->klass()->external_name());
1129 }
1130 }
1131
1132 void JavaThread::install_async_exception(AsyncExceptionHandshake* aeh) {
1133 // Do not throw asynchronous exceptions against the compiler thread
1134 // or if the thread is already exiting.
1135 if (!can_call_java() || is_exiting()) {
1136 delete aeh;
1137 return;
1138 }
1139
1140 oop exception = aeh->exception();
1141 Handshake::execute(aeh, this); // Install asynchronous handshake
1142
1143 ResourceMark rm;
1144 if (log_is_enabled(Info, exceptions)) {
1145 log_info(exceptions)("Pending Async. exception installed of type: %s",
1146 InstanceKlass::cast(exception->klass())->external_name());
1147 }
1148 // for AbortVMOnException flag
1149 Exceptions::debug_check_abort(exception->klass()->external_name());
1150
1151 oop vt_oop = vthread();
1152 if (vt_oop == nullptr || !vt_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1153 // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1154 java_lang_Thread::set_interrupted(threadObj(), true);
1155 this->interrupt();
1156 }
1157 }
1158
1159 class InstallAsyncExceptionHandshake : public HandshakeClosure {
1160 AsyncExceptionHandshake* _aeh;
1161 public:
1162 InstallAsyncExceptionHandshake(AsyncExceptionHandshake* aeh) :
1163 HandshakeClosure("InstallAsyncException"), _aeh(aeh) {}
1164 ~InstallAsyncExceptionHandshake() {
1165 // If InstallAsyncExceptionHandshake was never executed we need to clean up _aeh.
1166 delete _aeh;
1167 }
1168 void do_thread(Thread* thr) {
1169 JavaThread* target = JavaThread::cast(thr);
1170 target->install_async_exception(_aeh);
1171 _aeh = nullptr;
1172 }
1173 };
1174
1175 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
1176 OopHandle e(Universe::vm_global(), java_throwable);
1177 InstallAsyncExceptionHandshake iaeh(new AsyncExceptionHandshake(e));
1178 Handshake::execute(&iaeh, target);
1179 }
1180
1181 #if INCLUDE_JVMTI
1182 void JavaThread::set_is_in_VTMS_transition(bool val) {
1183 assert(is_in_VTMS_transition() != val, "already %s transition", val ? "inside" : "outside");
1184 _is_in_VTMS_transition = val;
1185 }
1186
1187 #ifdef ASSERT
1188 void JavaThread::set_is_VTMS_transition_disabler(bool val) {
1189 _is_VTMS_transition_disabler = val;
1190 }
1191 #endif
1192 #endif
1193
1194 // External suspension mechanism.
1195 //
1196 // Guarantees on return (for a valid target thread):
1197 // - Target thread will not execute any new bytecode.
1198 // - Target thread will not enter any new monitors.
1199 //
1200 bool JavaThread::java_suspend() {
1201 #if INCLUDE_JVMTI
1202 // Suspending a JavaThread in VTMS transition or disabling VTMS transitions can cause deadlocks.
1203 assert(!is_in_VTMS_transition(), "no suspend allowed in VTMS transition");
1204 assert(!is_VTMS_transition_disabler(), "no suspend allowed for VTMS transition disablers");
1205 #endif
1206
1207 guarantee(Thread::is_JavaThread_protected(/* target */ this),
1208 "target JavaThread is not protected in calling context.");
1209 return this->handshake_state()->suspend();
1210 }
1211
1212 bool JavaThread::java_resume() {
1213 guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1214 "missing ThreadsListHandle in calling context.");
1215 return this->handshake_state()->resume();
1216 }
1217
1218 // Wait for another thread to perform object reallocation and relocking on behalf of
1219 // this thread. The current thread is required to change to _thread_blocked in order
1220 // to be seen to be safepoint/handshake safe whilst suspended and only after becoming
1221 // handshake safe, the other thread can complete the handshake used to synchronize
1222 // with this thread and then perform the reallocation and relocking.
1223 // See EscapeBarrier::sync_and_suspend_*()
1224
1225 void JavaThread::wait_for_object_deoptimization() {
1226 assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1227 assert(this == Thread::current(), "invariant");
1228
1229 bool spin_wait = os::is_MP();
1230 do {
1231 ThreadBlockInVM tbivm(this, true /* allow_suspend */);
1232 // Wait for object deoptimization if requested.
1233 if (spin_wait) {
1234 // A single deoptimization is typically very short. Microbenchmarks
1235 // showed 5% better performance when spinning.
1236 const uint spin_limit = 10 * SpinYield::default_spin_limit;
1237 SpinYield spin(spin_limit);
1238 for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1239 spin.wait();
1240 }
1241 // Spin just once
1242 spin_wait = false;
1243 } else {
1244 MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1245 if (is_obj_deopt_suspend()) {
1246 ml.wait();
1247 }
1248 }
1249 // A handshake for obj. deoptimization suspend could have been processed so
1250 // we must check after processing.
1251 } while (is_obj_deopt_suspend());
1252 }
1253
1254 #ifdef ASSERT
1255 // Verify the JavaThread has not yet been published in the Threads::list, and
1256 // hence doesn't need protection from concurrent access at this stage.
1257 void JavaThread::verify_not_published() {
1258 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1259 // since an unpublished JavaThread doesn't participate in the
1260 // Thread-SMR protocol for keeping a ThreadsList alive.
1261 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1262 }
1263 #endif
1264
1265 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1266 // pending, when _suspend_flags is non-zero or when we need to process a stack
1267 // watermark. Also check for pending async exceptions (except unsafe access error).
1268 // Note only the native==>Java barriers can call this function when thread state
1269 // is _thread_in_native_trans.
1270 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1271 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1272 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1273
1274 thread->set_thread_state(_thread_in_vm);
1275
1276 // Enable WXWrite: called directly from interpreter native wrapper.
1277 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1278
1279 SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
1280
1281 // After returning from native, it could be that the stack frames are not
1282 // yet safe to use. We catch such situations in the subsequent stack watermark
1283 // barrier, which will trap unsafe stack frames.
1284 StackWatermarkSet::before_unwind(thread);
1285 }
1286
1287 #ifndef PRODUCT
1288 // Deoptimization
1289 // Function for testing deoptimization
1290 void JavaThread::deoptimize() {
1291 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1292 bool deopt = false; // Dump stack only if a deopt actually happens.
1293 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1294 // Iterate over all frames in the thread and deoptimize
1295 for (; !fst.is_done(); fst.next()) {
1296 if (fst.current()->can_be_deoptimized()) {
1297
1298 if (only_at) {
1299 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
1300 // consists of comma or carriage return separated numbers so
1301 // search for the current bci in that string.
1302 address pc = fst.current()->pc();
1303 nmethod* nm = fst.current()->cb()->as_nmethod();
1304 ScopeDesc* sd = nm->scope_desc_at(pc);
1305 char buffer[8];
1306 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1307 size_t len = strlen(buffer);
1308 const char * found = strstr(DeoptimizeOnlyAt, buffer);
1309 while (found != nullptr) {
1310 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1311 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1312 // Check that the bci found is bracketed by terminators.
1313 break;
1314 }
1315 found = strstr(found + 1, buffer);
1316 }
1317 if (!found) {
1318 continue;
1319 }
1320 }
1321
1322 if (DebugDeoptimization && !deopt) {
1323 deopt = true; // One-time only print before deopt
1324 tty->print_cr("[BEFORE Deoptimization]");
1325 trace_frames();
1326 trace_stack();
1327 }
1328 Deoptimization::deoptimize(this, *fst.current());
1329 }
1330 }
1331
1332 if (DebugDeoptimization && deopt) {
1333 tty->print_cr("[AFTER Deoptimization]");
1334 trace_frames();
1335 }
1336 }
1337
1338
1339 // Make zombies
1340 void JavaThread::make_zombies() {
1341 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1342 if (fst.current()->can_be_deoptimized()) {
1343 // it is a Java nmethod
1344 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1345 assert(nm != nullptr, "did not find nmethod");
1346 nm->make_not_entrant();
1347 }
1348 }
1349 }
1350 #endif // PRODUCT
1351
1352
1353 void JavaThread::deoptimize_marked_methods() {
1354 if (!has_last_Java_frame()) return;
1355 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1356 for (; !fst.is_done(); fst.next()) {
1357 if (fst.current()->should_be_deoptimized()) {
1358 Deoptimization::deoptimize(this, *fst.current());
1359 }
1360 }
1361 }
1362
1363 #ifdef ASSERT
1364 void JavaThread::verify_frame_info() {
1365 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1366 (has_last_Java_frame() && java_call_counter() > 0),
1367 "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1368 has_last_Java_frame() ? "true" : "false", java_call_counter());
1369 }
1370 #endif
1371
1372 // Push on a new block of JNI handles.
1373 void JavaThread::push_jni_handle_block() {
1374 // Allocate a new block for JNI handles.
1375 // Inlined code from jni_PushLocalFrame()
1376 JNIHandleBlock* old_handles = active_handles();
1377 JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this);
1378 assert(old_handles != nullptr && new_handles != nullptr, "should not be null");
1379 new_handles->set_pop_frame_link(old_handles); // make sure java handles get gc'd.
1380 set_active_handles(new_handles);
1381 }
1382
1383 // Pop off the current block of JNI handles.
1384 void JavaThread::pop_jni_handle_block() {
1385 // Release our JNI handle block
1386 JNIHandleBlock* old_handles = active_handles();
1387 JNIHandleBlock* new_handles = old_handles->pop_frame_link();
1388 assert(new_handles != nullptr, "should never set active handles to null");
1389 set_active_handles(new_handles);
1390 old_handles->set_pop_frame_link(nullptr);
1391 JNIHandleBlock::release_block(old_handles, this);
1392 }
1393
1394 void JavaThread::oops_do_no_frames(OopClosure* f, NMethodClosure* cf) {
1395 // Verify that the deferred card marks have been flushed.
1396 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1397
1398 // Traverse the GCHandles
1399 Thread::oops_do_no_frames(f, cf);
1400
1401 if (active_handles() != nullptr) {
1402 active_handles()->oops_do(f);
1403 }
1404
1405 DEBUG_ONLY(verify_frame_info();)
1406
1407 assert(vframe_array_head() == nullptr, "deopt in progress at a safepoint!");
1408 // If we have deferred set_locals there might be oops waiting to be
1409 // written
1410 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1411 if (list != nullptr) {
1412 for (int i = 0; i < list->length(); i++) {
1413 list->at(i)->oops_do(f);
1414 }
1415 }
1416
1417 // Traverse instance variables at the end since the GC may be moving things
1418 // around using this function
1419 f->do_oop((oop*) &_vm_result);
1420 f->do_oop((oop*) &_exception_oop);
1421 #if INCLUDE_JVMCI
1422 f->do_oop((oop*) &_jvmci_reserved_oop0);
1423
1424 if (_live_nmethod != nullptr && cf != nullptr) {
1425 cf->do_nmethod(_live_nmethod);
1426 }
1427 #endif
1428
1429 if (jvmti_thread_state() != nullptr) {
1430 jvmti_thread_state()->oops_do(f, cf);
1431 }
1432
1433 // The continuation oops are really on the stack. But there is typically at most
1434 // one of those per thread, so we handle them here in the oops_do_no_frames part
1435 // so that we don't have to sprinkle as many stack watermark checks where these
1436 // oops are used. We just need to make sure the thread has started processing.
1437 ContinuationEntry* entry = _cont_entry;
1438 while (entry != nullptr) {
1439 f->do_oop((oop*)entry->cont_addr());
1440 f->do_oop((oop*)entry->chunk_addr());
1441 entry = entry->parent();
1442 }
1443
1444 if (LockingMode == LM_LIGHTWEIGHT) {
1445 lock_stack().oops_do(f);
1446 }
1447 }
1448
1449 void JavaThread::oops_do_frames(OopClosure* f, NMethodClosure* cf) {
1450 if (!has_last_Java_frame()) {
1451 return;
1452 }
1453 // Finish any pending lazy GC activity for the frames
1454 StackWatermarkSet::finish_processing(this, nullptr /* context */, StackWatermarkKind::gc);
1455 // Traverse the execution stack
1456 for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1457 fst.current()->oops_do(f, cf, fst.register_map());
1458 }
1459 }
1460
1461 #ifdef ASSERT
1462 void JavaThread::verify_states_for_handshake() {
1463 // This checks that the thread has a correct frame state during a handshake.
1464 verify_frame_info();
1465 }
1466 #endif
1467
1468 void JavaThread::nmethods_do(NMethodClosure* cf) {
1469 DEBUG_ONLY(verify_frame_info();)
1470 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current());)
1471
1472 if (has_last_Java_frame()) {
1473 // Traverse the execution stack
1474 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1475 fst.current()->nmethod_do(cf);
1476 }
1477 }
1478
1479 if (jvmti_thread_state() != nullptr) {
1480 jvmti_thread_state()->nmethods_do(cf);
1481 }
1482
1483 #if INCLUDE_JVMCI
1484 if (_live_nmethod != nullptr) {
1485 cf->do_nmethod(_live_nmethod);
1486 }
1487 #endif
1488 }
1489
1490 void JavaThread::metadata_do(MetadataClosure* f) {
1491 if (has_last_Java_frame()) {
1492 // Traverse the execution stack to call f() on the methods in the stack
1493 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1494 fst.current()->metadata_do(f);
1495 }
1496 } else if (is_Compiler_thread()) {
1497 // need to walk ciMetadata in current compile tasks to keep alive.
1498 CompilerThread* ct = (CompilerThread*)this;
1499 if (ct->env() != nullptr) {
1500 ct->env()->metadata_do(f);
1501 }
1502 CompileTask* task = ct->task();
1503 if (task != nullptr) {
1504 task->metadata_do(f);
1505 }
1506 }
1507 }
1508
1509 // Printing
1510 static const char* _get_thread_state_name(JavaThreadState _thread_state) {
1511 switch (_thread_state) {
1512 case _thread_uninitialized: return "_thread_uninitialized";
1513 case _thread_new: return "_thread_new";
1514 case _thread_new_trans: return "_thread_new_trans";
1515 case _thread_in_native: return "_thread_in_native";
1516 case _thread_in_native_trans: return "_thread_in_native_trans";
1517 case _thread_in_vm: return "_thread_in_vm";
1518 case _thread_in_vm_trans: return "_thread_in_vm_trans";
1519 case _thread_in_Java: return "_thread_in_Java";
1520 case _thread_in_Java_trans: return "_thread_in_Java_trans";
1521 case _thread_blocked: return "_thread_blocked";
1522 case _thread_blocked_trans: return "_thread_blocked_trans";
1523 default: return "unknown thread state";
1524 }
1525 }
1526
1527 void JavaThread::print_thread_state_on(outputStream *st) const {
1528 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
1529 }
1530
1531 // Called by Threads::print() for VM_PrintThreads operation
1532 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
1533 st->print_raw("\"");
1534 st->print_raw(name());
1535 st->print_raw("\" ");
1536 oop thread_oop = threadObj();
1537 if (thread_oop != nullptr) {
1538 st->print("#" INT64_FORMAT " [%ld] ", (int64_t)java_lang_Thread::thread_id(thread_oop), (long) osthread()->thread_id());
1539 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
1540 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
1541 }
1542 Thread::print_on(st, print_extended_info);
1543 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
1544 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
1545 if (thread_oop != nullptr) {
1546 if (is_vthread_mounted()) {
1547 st->print_cr(" Carrying virtual thread #" INT64_FORMAT, java_lang_Thread::thread_id(vthread()));
1548 } else {
1549 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
1550 }
1551 }
1552 #ifndef PRODUCT
1553 _safepoint_state->print_on(st);
1554 #endif // PRODUCT
1555 if (is_Compiler_thread()) {
1556 CompileTask *task = ((CompilerThread*)this)->task();
1557 if (task != nullptr) {
1558 st->print(" Compiling: ");
1559 task->print(st, nullptr, true, false);
1560 } else {
1561 st->print(" No compile task");
1562 }
1563 st->cr();
1564 }
1565 }
1566
1567 void JavaThread::print() const { print_on(tty); }
1568
1569 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
1570 st->print("%s", get_thread_name_string(buf, buflen));
1571 }
1572
1573 // Called by fatal error handler. The difference between this and
1574 // JavaThread::print() is that we can't grab lock or allocate memory.
1575 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
1576 st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
1577 Thread* current = Thread::current_or_null_safe();
1578 assert(current != nullptr, "cannot be called by a detached thread");
1579 st->fill_to(60);
1580 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1581 // Only access threadObj() if current thread is not a JavaThread
1582 // or if it is a JavaThread that can safely access oops.
1583 oop thread_obj = threadObj();
1584 if (thread_obj != nullptr) {
1585 st->print(java_lang_Thread::is_daemon(thread_obj) ? " daemon" : " ");
1586 }
1587 }
1588 st->print(" [");
1589 st->print("%s", _get_thread_state_name(_thread_state));
1590 if (osthread()) {
1591 st->print(", id=%d", osthread()->thread_id());
1592 }
1593 // Use raw field members for stack base/size as this could be
1594 // called before a thread has run enough to initialize them.
1595 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ") (" PROPERFMT ")",
1596 p2i(_stack_base - _stack_size), p2i(_stack_base),
1597 PROPERFMTARGS(_stack_size));
1598 st->print("]");
1599
1600 ThreadsSMRSupport::print_info_on(this, st);
1601 return;
1602 }
1603
1604
1605 // Verification
1606
1607 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
1608 // ignore if there is no stack
1609 if (!has_last_Java_frame()) return;
1610 // traverse the stack frames. Starts from top frame.
1611 for (StackFrameStream fst(this, true /* update_map */, true /* process_frames */, false /* walk_cont */); !fst.is_done(); fst.next()) {
1612 frame* fr = fst.current();
1613 f(fr, fst.register_map());
1614 }
1615 }
1616
1617 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
1618
1619 void JavaThread::verify() {
1620 // Verify oops in the thread.
1621 oops_do(&VerifyOopClosure::verify_oop, nullptr);
1622
1623 // Verify the stack frames.
1624 frames_do(frame_verify);
1625 }
1626
1627 // CR 6300358 (sub-CR 2137150)
1628 // Most callers of this method assume that it can't return null but a
1629 // thread may not have a name whilst it is in the process of attaching to
1630 // the VM - see CR 6412693, and there are places where a JavaThread can be
1631 // seen prior to having its threadObj set (e.g., JNI attaching threads and
1632 // if vm exit occurs during initialization). These cases can all be accounted
1633 // for such that this method never returns null.
1634 const char* JavaThread::name() const {
1635 if (Thread::is_JavaThread_protected(/* target */ this)) {
1636 // The target JavaThread is protected so get_thread_name_string() is safe:
1637 return get_thread_name_string();
1638 }
1639
1640 // The target JavaThread is not protected so we return the default:
1641 return Thread::name();
1642 }
1643
1644 // Like name() but doesn't include the protection check. This must only be
1645 // called when it is known to be safe, even though the protection check can't tell
1646 // that e.g. when this thread is the init_thread() - see instanceKlass.cpp.
1647 const char* JavaThread::name_raw() const {
1648 return get_thread_name_string();
1649 }
1650
1651 // Returns a non-null representation of this thread's name, or a suitable
1652 // descriptive string if there is no set name.
1653 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
1654 const char* name_str;
1655 #ifdef ASSERT
1656 Thread* current = Thread::current_or_null_safe();
1657 assert(current != nullptr, "cannot be called by a detached thread");
1658 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1659 // Only access threadObj() if current thread is not a JavaThread
1660 // or if it is a JavaThread that can safely access oops.
1661 #endif
1662 oop thread_obj = threadObj();
1663 if (thread_obj != nullptr) {
1664 oop name = java_lang_Thread::name(thread_obj);
1665 if (name != nullptr) {
1666 if (buf == nullptr) {
1667 name_str = java_lang_String::as_utf8_string(name);
1668 } else {
1669 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
1670 }
1671 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
1672 name_str = "<no-name - thread is attaching>";
1673 } else {
1674 name_str = "<un-named>";
1675 }
1676 } else {
1677 name_str = Thread::name();
1678 }
1679 #ifdef ASSERT
1680 } else {
1681 // Current JavaThread has exited...
1682 if (current == this) {
1683 // ... and is asking about itself:
1684 name_str = "<no-name - current JavaThread has exited>";
1685 } else {
1686 // ... and it can't safely determine this JavaThread's name so
1687 // use the default thread name.
1688 name_str = Thread::name();
1689 }
1690 }
1691 #endif
1692 assert(name_str != nullptr, "unexpected null thread name");
1693 return name_str;
1694 }
1695
1696 // Helper to extract the name from the thread oop for logging.
1697 const char* JavaThread::name_for(oop thread_obj) {
1698 assert(thread_obj != nullptr, "precondition");
1699 oop name = java_lang_Thread::name(thread_obj);
1700 const char* name_str;
1701 if (name != nullptr) {
1702 name_str = java_lang_String::as_utf8_string(name);
1703 } else {
1704 name_str = "<un-named>";
1705 }
1706 return name_str;
1707 }
1708
1709 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
1710
1711 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
1712 assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
1713 // Link Java Thread object <-> C++ Thread
1714
1715 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
1716 // and put it into a new Handle. The Handle "thread_oop" can then
1717 // be used to pass the C++ thread object to other methods.
1718
1719 // Set the Java level thread object (jthread) field of the
1720 // new thread (a JavaThread *) to C++ thread object using the
1721 // "thread_oop" handle.
1722
1723 // Set the thread field (a JavaThread *) of the
1724 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
1725
1726 Handle thread_oop(Thread::current(),
1727 JNIHandles::resolve_non_null(jni_thread));
1728 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
1729 "must be initialized");
1730 set_threadOopHandles(thread_oop());
1731 set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
1732
1733 if (prio == NoPriority) {
1734 prio = java_lang_Thread::priority(thread_oop());
1735 assert(prio != NoPriority, "A valid priority should be present");
1736 }
1737
1738 // Push the Java priority down to the native thread; needs Threads_lock
1739 Thread::set_priority(this, prio);
1740
1741 // Add the new thread to the Threads list and set it in motion.
1742 // We must have threads lock in order to call Threads::add.
1743 // It is crucial that we do not block before the thread is
1744 // added to the Threads list for if a GC happens, then the java_thread oop
1745 // will not be visited by GC.
1746 Threads::add(this);
1747 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
1748 // on a ThreadsList. We don't want to wait for the release when the
1749 // Theads_lock is dropped somewhere in the caller since the JavaThread*
1750 // is already visible to JVM/TI via the ThreadsList.
1751 java_lang_Thread::release_set_thread(thread_oop(), this);
1752 }
1753
1754 oop JavaThread::current_park_blocker() {
1755 // Support for JSR-166 locks
1756 oop thread_oop = threadObj();
1757 if (thread_oop != nullptr) {
1758 return java_lang_Thread::park_blocker(thread_oop);
1759 }
1760 return nullptr;
1761 }
1762
1763 // Print current stack trace for checked JNI warnings and JNI fatal errors.
1764 // This is the external format, selecting the platform or vthread
1765 // as applicable, and allowing for a native-only stack.
1766 void JavaThread::print_jni_stack() {
1767 assert(this == JavaThread::current(), "Can't print stack of other threads");
1768 if (!has_last_Java_frame()) {
1769 ResourceMark rm(this);
1770 char* buf = NEW_RESOURCE_ARRAY_RETURN_NULL(char, O_BUFLEN);
1771 if (buf == nullptr) {
1772 tty->print_cr("Unable to print native stack - out of memory");
1773 return;
1774 }
1775 NativeStackPrinter nsp(this);
1776 address lastpc = nullptr;
1777 nsp.print_stack(tty, buf, O_BUFLEN, lastpc,
1778 true /*print_source_info */, -1 /* max stack */ );
1779 } else {
1780 print_active_stack_on(tty);
1781 }
1782 }
1783
1784 void JavaThread::print_stack_on(outputStream* st) {
1785 if (!has_last_Java_frame()) return;
1786
1787 Thread* current_thread = Thread::current();
1788 ResourceMark rm(current_thread);
1789 HandleMark hm(current_thread);
1790
1791 RegisterMap reg_map(this,
1792 RegisterMap::UpdateMap::include,
1793 RegisterMap::ProcessFrames::include,
1794 RegisterMap::WalkContinuation::skip);
1795 vframe* start_vf = platform_thread_last_java_vframe(®_map);
1796 int count = 0;
1797 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1798 if (f->is_java_frame()) {
1799 javaVFrame* jvf = javaVFrame::cast(f);
1800 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1801
1802 // Print out lock information
1803 if (JavaMonitorsInStackTrace) {
1804 jvf->print_lock_info_on(st, count);
1805 }
1806 } else {
1807 // Ignore non-Java frames
1808 }
1809
1810 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1811 count++;
1812 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1813 }
1814 }
1815
1816 void JavaThread::print_vthread_stack_on(outputStream* st) {
1817 assert(is_vthread_mounted(), "Caller should have checked this");
1818 assert(has_last_Java_frame(), "must be");
1819
1820 Thread* current_thread = Thread::current();
1821 ResourceMark rm(current_thread);
1822 HandleMark hm(current_thread);
1823
1824 RegisterMap reg_map(this,
1825 RegisterMap::UpdateMap::include,
1826 RegisterMap::ProcessFrames::include,
1827 RegisterMap::WalkContinuation::include);
1828 ContinuationEntry* cont_entry = last_continuation();
1829 vframe* start_vf = last_java_vframe(®_map);
1830 int count = 0;
1831 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1832 // Watch for end of vthread stack
1833 if (Continuation::is_continuation_enterSpecial(f->fr())) {
1834 assert(cont_entry == Continuation::get_continuation_entry_for_entry_frame(this, f->fr()), "");
1835 if (cont_entry->is_virtual_thread()) {
1836 break;
1837 }
1838 cont_entry = cont_entry->parent();
1839 }
1840 if (f->is_java_frame()) {
1841 javaVFrame* jvf = javaVFrame::cast(f);
1842 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1843
1844 // Print out lock information
1845 if (JavaMonitorsInStackTrace) {
1846 jvf->print_lock_info_on(st, count);
1847 }
1848 } else {
1849 // Ignore non-Java frames
1850 }
1851
1852 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1853 count++;
1854 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1855 }
1856 }
1857
1858 void JavaThread::print_active_stack_on(outputStream* st) {
1859 if (is_vthread_mounted()) {
1860 print_vthread_stack_on(st);
1861 } else {
1862 print_stack_on(st);
1863 }
1864 }
1865
1866 #if INCLUDE_JVMTI
1867 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1868 JvmtiThreadState* JavaThread::rebind_to_jvmti_thread_state_of(oop thread_oop) {
1869 set_jvmti_vthread(thread_oop);
1870
1871 // unbind current JvmtiThreadState from JavaThread
1872 JvmtiThreadState::unbind_from(jvmti_thread_state(), this);
1873
1874 // bind new JvmtiThreadState to JavaThread
1875 JvmtiThreadState::bind_to(java_lang_Thread::jvmti_thread_state(thread_oop), this);
1876
1877 // enable interp_only_mode for virtual or carrier thread if it has pending bit
1878 JvmtiThreadState::process_pending_interp_only(this);
1879
1880 return jvmti_thread_state();
1881 }
1882 #endif
1883
1884 // JVMTI PopFrame support
1885 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
1886 assert(_popframe_preserved_args == nullptr, "should not wipe out old PopFrame preserved arguments");
1887 if (in_bytes(size_in_bytes) != 0) {
1888 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
1889 _popframe_preserved_args_size = in_bytes(size_in_bytes);
1890 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
1891 }
1892 }
1893
1894 void* JavaThread::popframe_preserved_args() {
1895 return _popframe_preserved_args;
1896 }
1897
1898 ByteSize JavaThread::popframe_preserved_args_size() {
1899 return in_ByteSize(_popframe_preserved_args_size);
1900 }
1901
1902 WordSize JavaThread::popframe_preserved_args_size_in_words() {
1903 int sz = in_bytes(popframe_preserved_args_size());
1904 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
1905 return in_WordSize(sz / wordSize);
1906 }
1907
1908 void JavaThread::popframe_free_preserved_args() {
1909 assert(_popframe_preserved_args != nullptr, "should not free PopFrame preserved arguments twice");
1910 FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
1911 _popframe_preserved_args = nullptr;
1912 _popframe_preserved_args_size = 0;
1913 }
1914
1915 #ifndef PRODUCT
1916
1917 void JavaThread::trace_frames() {
1918 tty->print_cr("[Describe stack]");
1919 int frame_no = 1;
1920 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1921 tty->print(" %d. ", frame_no++);
1922 fst.current()->print_value_on(tty);
1923 tty->cr();
1924 }
1925 }
1926
1927 class PrintAndVerifyOopClosure: public OopClosure {
1928 protected:
1929 template <class T> inline void do_oop_work(T* p) {
1930 oop obj = RawAccess<>::oop_load(p);
1931 if (obj == nullptr) return;
1932 tty->print(INTPTR_FORMAT ": ", p2i(p));
1933 if (oopDesc::is_oop_or_null(obj)) {
1934 if (obj->is_objArray()) {
1935 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
1936 } else {
1937 obj->print();
1938 }
1939 } else {
1940 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
1941 }
1942 tty->cr();
1943 }
1944 public:
1945 virtual void do_oop(oop* p) { do_oop_work(p); }
1946 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1947 };
1948
1949 #ifdef ASSERT
1950 // Print or validate the layout of stack frames
1951 void JavaThread::print_frame_layout(int depth, bool validate_only) {
1952 ResourceMark rm;
1953 PreserveExceptionMark pm(this);
1954 FrameValues values;
1955 int frame_no = 0;
1956 for (StackFrameStream fst(this, true, true, true); !fst.is_done(); fst.next()) {
1957 fst.current()->describe(values, ++frame_no, fst.register_map());
1958 if (depth == frame_no) break;
1959 }
1960 Continuation::describe(values);
1961 if (validate_only) {
1962 values.validate();
1963 } else {
1964 tty->print_cr("[Describe stack layout]");
1965 values.print(this);
1966 }
1967 }
1968 #endif
1969
1970 void JavaThread::trace_stack_from(vframe* start_vf) {
1971 ResourceMark rm;
1972 int vframe_no = 1;
1973 for (vframe* f = start_vf; f; f = f->sender()) {
1974 if (f->is_java_frame()) {
1975 javaVFrame::cast(f)->print_activation(vframe_no++);
1976 } else {
1977 f->print();
1978 }
1979 if (vframe_no > StackPrintLimit) {
1980 tty->print_cr("...<more frames>...");
1981 return;
1982 }
1983 }
1984 }
1985
1986
1987 void JavaThread::trace_stack() {
1988 if (!has_last_Java_frame()) return;
1989 Thread* current_thread = Thread::current();
1990 ResourceMark rm(current_thread);
1991 HandleMark hm(current_thread);
1992 RegisterMap reg_map(this,
1993 RegisterMap::UpdateMap::include,
1994 RegisterMap::ProcessFrames::include,
1995 RegisterMap::WalkContinuation::skip);
1996 trace_stack_from(last_java_vframe(®_map));
1997 }
1998
1999
2000 #endif // PRODUCT
2001
2002 // Slow-path increment of the held monitor counts. JNI locking is always
2003 // this slow-path.
2004 void JavaThread::inc_held_monitor_count(intx i, bool jni) {
2005 #ifdef SUPPORT_MONITOR_COUNT
2006
2007 if (LockingMode != LM_LEGACY) {
2008 // Nothing to do. Just do some sanity check.
2009 assert(_held_monitor_count == 0, "counter should not be used");
2010 assert(_jni_monitor_count == 0, "counter should not be used");
2011 return;
2012 }
2013
2014 assert(_held_monitor_count >= 0, "Must always be non-negative: %zd", _held_monitor_count);
2015 _held_monitor_count += i;
2016 if (jni) {
2017 assert(_jni_monitor_count >= 0, "Must always be non-negative: %zd", _jni_monitor_count);
2018 _jni_monitor_count += i;
2019 }
2020 assert(_held_monitor_count >= _jni_monitor_count, "Monitor count discrepancy detected - held count "
2021 "%zd is less than JNI count %zd", _held_monitor_count, _jni_monitor_count);
2022 #endif // SUPPORT_MONITOR_COUNT
2023 }
2024
2025 // Slow-path decrement of the held monitor counts. JNI unlocking is always
2026 // this slow-path.
2027 void JavaThread::dec_held_monitor_count(intx i, bool jni) {
2028 #ifdef SUPPORT_MONITOR_COUNT
2029
2030 if (LockingMode != LM_LEGACY) {
2031 // Nothing to do. Just do some sanity check.
2032 assert(_held_monitor_count == 0, "counter should not be used");
2033 assert(_jni_monitor_count == 0, "counter should not be used");
2034 return;
2035 }
2036
2037 _held_monitor_count -= i;
2038 assert(_held_monitor_count >= 0, "Must always be non-negative: %zd", _held_monitor_count);
2039 if (jni) {
2040 _jni_monitor_count -= i;
2041 assert(_jni_monitor_count >= 0, "Must always be non-negative: %zd", _jni_monitor_count);
2042 }
2043 // When a thread is detaching with still owned JNI monitors, the logic that releases
2044 // the monitors doesn't know to set the "jni" flag and so the counts can get out of sync.
2045 // So we skip this assert if the thread is exiting. Once all monitors are unlocked the
2046 // JNI count is directly set to zero.
2047 assert(_held_monitor_count >= _jni_monitor_count || is_exiting(), "Monitor count discrepancy detected - held count "
2048 "%zd is less than JNI count %zd", _held_monitor_count, _jni_monitor_count);
2049 #endif // SUPPORT_MONITOR_COUNT
2050 }
2051
2052 frame JavaThread::vthread_last_frame() {
2053 assert (is_vthread_mounted(), "Virtual thread not mounted");
2054 return last_frame();
2055 }
2056
2057 frame JavaThread::carrier_last_frame(RegisterMap* reg_map) {
2058 const ContinuationEntry* entry = vthread_continuation();
2059 guarantee (entry != nullptr, "Not a carrier thread");
2060 frame f = entry->to_frame();
2061 if (reg_map->process_frames()) {
2062 entry->flush_stack_processing(this);
2063 }
2064 entry->update_register_map(reg_map);
2065 return f.sender(reg_map);
2066 }
2067
2068 frame JavaThread::platform_thread_last_frame(RegisterMap* reg_map) {
2069 return is_vthread_mounted() ? carrier_last_frame(reg_map) : last_frame();
2070 }
2071
2072 javaVFrame* JavaThread::last_java_vframe(const frame f, RegisterMap *reg_map) {
2073 assert(reg_map != nullptr, "a map must be given");
2074 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
2075 if (vf->is_java_frame()) return javaVFrame::cast(vf);
2076 }
2077 return nullptr;
2078 }
2079
2080 Klass* JavaThread::security_get_caller_class(int depth) {
2081 ResetNoHandleMark rnhm;
2082 HandleMark hm(Thread::current());
2083
2084 vframeStream vfst(this);
2085 vfst.security_get_caller_frame(depth);
2086 if (!vfst.at_end()) {
2087 return vfst.method()->method_holder();
2088 }
2089 return nullptr;
2090 }
2091
2092 // Internal convenience function for millisecond resolution sleeps.
2093 bool JavaThread::sleep(jlong millis) {
2094 jlong nanos;
2095 if (millis > max_jlong / NANOUNITS_PER_MILLIUNIT) {
2096 // Conversion to nanos would overflow, saturate at max
2097 nanos = max_jlong;
2098 } else {
2099 nanos = millis * NANOUNITS_PER_MILLIUNIT;
2100 }
2101 return sleep_nanos(nanos);
2102 }
2103
2104 // java.lang.Thread.sleep support
2105 // Returns true if sleep time elapsed as expected, and false
2106 // if the thread was interrupted.
2107 bool JavaThread::sleep_nanos(jlong nanos) {
2108 assert(this == Thread::current(), "thread consistency check");
2109 assert(nanos >= 0, "nanos are in range");
2110
2111 ParkEvent * const slp = this->_SleepEvent;
2112 // Because there can be races with thread interruption sending an unpark()
2113 // to the event, we explicitly reset it here to avoid an immediate return.
2114 // The actual interrupt state will be checked before we park().
2115 slp->reset();
2116 // Thread interruption establishes a happens-before ordering in the
2117 // Java Memory Model, so we need to ensure we synchronize with the
2118 // interrupt state.
2119 OrderAccess::fence();
2120
2121 jlong prevtime = os::javaTimeNanos();
2122
2123 jlong nanos_remaining = nanos;
2124
2125 for (;;) {
2126 // interruption has precedence over timing out
2127 if (this->is_interrupted(true)) {
2128 return false;
2129 }
2130
2131 if (nanos_remaining <= 0) {
2132 return true;
2133 }
2134
2135 {
2136 ThreadBlockInVM tbivm(this);
2137 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
2138 slp->park_nanos(nanos_remaining);
2139 }
2140
2141 // Update elapsed time tracking
2142 jlong newtime = os::javaTimeNanos();
2143 if (newtime - prevtime < 0) {
2144 // time moving backwards, should only happen if no monotonic clock
2145 // not a guarantee() because JVM should not abort on kernel/glibc bugs
2146 assert(false,
2147 "unexpected time moving backwards detected in JavaThread::sleep()");
2148 } else {
2149 nanos_remaining -= (newtime - prevtime);
2150 }
2151 prevtime = newtime;
2152 }
2153 }
2154
2155 // Last thread running calls java.lang.Shutdown.shutdown()
2156 void JavaThread::invoke_shutdown_hooks() {
2157 HandleMark hm(this);
2158
2159 // We could get here with a pending exception, if so clear it now.
2160 if (this->has_pending_exception()) {
2161 this->clear_pending_exception();
2162 }
2163
2164 EXCEPTION_MARK;
2165 Klass* shutdown_klass =
2166 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
2167 THREAD);
2168 if (shutdown_klass != nullptr) {
2169 // SystemDictionary::resolve_or_null will return null if there was
2170 // an exception. If we cannot load the Shutdown class, just don't
2171 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
2172 // won't be run. Note that if a shutdown hook was registered,
2173 // the Shutdown class would have already been loaded
2174 // (Runtime.addShutdownHook will load it).
2175 JavaValue result(T_VOID);
2176 JavaCalls::call_static(&result,
2177 shutdown_klass,
2178 vmSymbols::shutdown_name(),
2179 vmSymbols::void_method_signature(),
2180 THREAD);
2181 }
2182 CLEAR_PENDING_EXCEPTION;
2183 }
2184
2185 #ifndef PRODUCT
2186 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
2187 report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
2188 }
2189 #endif
2190
2191 // Helper function to create the java.lang.Thread object for a
2192 // VM-internal thread. The thread will have the given name, and be
2193 // a member of the "system" ThreadGroup.
2194 Handle JavaThread::create_system_thread_object(const char* name, TRAPS) {
2195 Handle string = java_lang_String::create_from_str(name, CHECK_NH);
2196
2197 // Initialize thread_oop to put it into the system threadGroup.
2198 // This is done by calling the Thread(ThreadGroup group, String name) constructor.
2199 Handle thread_group(THREAD, Universe::system_thread_group());
2200 Handle thread_oop =
2201 JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
2202 vmSymbols::threadgroup_string_void_signature(),
2203 thread_group,
2204 string,
2205 CHECK_NH);
2206
2207 return thread_oop;
2208 }
2209
2210 // Starts the target JavaThread as a daemon of the given priority, and
2211 // bound to the given java.lang.Thread instance.
2212 // The Threads_lock is held for the duration.
2213 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
2214 Handle thread_oop, ThreadPriority prio) {
2215
2216 assert(target->osthread() != nullptr, "target thread is not properly initialized");
2217
2218 MutexLocker mu(current, Threads_lock);
2219
2220 // Initialize the fields of the thread_oop first.
2221 if (prio != NoPriority) {
2222 java_lang_Thread::set_priority(thread_oop(), prio);
2223 // Note: we don't call os::set_priority here. Possibly we should,
2224 // else all threads should call it themselves when they first run.
2225 }
2226
2227 java_lang_Thread::set_daemon(thread_oop());
2228
2229 // Now bind the thread_oop to the target JavaThread.
2230 target->set_threadOopHandles(thread_oop());
2231 target->set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
2232
2233 Threads::add(target); // target is now visible for safepoint/handshake
2234 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
2235 // on a ThreadsList. We don't want to wait for the release when the
2236 // Theads_lock is dropped when the 'mu' destructor is run since the
2237 // JavaThread* is already visible to JVM/TI via the ThreadsList.
2238
2239 assert(java_lang_Thread::thread(thread_oop()) == nullptr, "must not be alive");
2240 java_lang_Thread::release_set_thread(thread_oop(), target); // isAlive == true now
2241 Thread::start(target);
2242 }
2243
2244 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
2245 // At this point it may be possible that no osthread was created for the
2246 // JavaThread due to lack of resources. However, since this must work
2247 // for critical system threads just check and abort if this fails.
2248 if (thread->osthread() == nullptr) {
2249 // This isn't really an OOM condition, but historically this is what
2250 // we report.
2251 vm_exit_during_initialization("java.lang.OutOfMemoryError",
2252 os::native_thread_creation_failed_msg());
2253 }
2254 }
2255
2256 void JavaThread::pretouch_stack() {
2257 // Given an established java thread stack with usable area followed by
2258 // shadow zone and reserved/yellow/red zone, pretouch the usable area ranging
2259 // from the current frame down to the start of the shadow zone.
2260 const address end = _stack_overflow_state.shadow_zone_safe_limit();
2261 if (is_in_full_stack(end)) {
2262 char* p1 = (char*) alloca(1);
2263 address here = (address) &p1;
2264 if (is_in_full_stack(here) && here > end) {
2265 size_t to_alloc = here - end;
2266 char* p2 = (char*) alloca(to_alloc);
2267 log_trace(os, thread)("Pretouching thread stack for %zu: " RANGEFMT ".",
2268 (uintx) osthread()->thread_id(), RANGEFMTARGS(p2, to_alloc));
2269 os::pretouch_memory(p2, p2 + to_alloc,
2270 NOT_AIX(os::vm_page_size()) AIX_ONLY(4096));
2271 }
2272 }
2273 }
2274
2275 // Deferred OopHandle release support.
2276
2277 class OopHandleList : public CHeapObj<mtInternal> {
2278 static const int _count = 4;
2279 OopHandle _handles[_count];
2280 OopHandleList* _next;
2281 int _index;
2282 public:
2283 OopHandleList(OopHandleList* next) : _next(next), _index(0) {}
2284 void add(OopHandle h) {
2285 assert(_index < _count, "too many additions");
2286 _handles[_index++] = h;
2287 }
2288 ~OopHandleList() {
2289 assert(_index == _count, "usage error");
2290 for (int i = 0; i < _index; i++) {
2291 _handles[i].release(JavaThread::thread_oop_storage());
2292 }
2293 }
2294 OopHandleList* next() const { return _next; }
2295 };
2296
2297 OopHandleList* JavaThread::_oop_handle_list = nullptr;
2298
2299 // Called by the ServiceThread to do the work of releasing
2300 // the OopHandles.
2301 void JavaThread::release_oop_handles() {
2302 OopHandleList* list;
2303 {
2304 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2305 list = _oop_handle_list;
2306 _oop_handle_list = nullptr;
2307 }
2308 assert(!SafepointSynchronize::is_at_safepoint(), "cannot be called at a safepoint");
2309
2310 while (list != nullptr) {
2311 OopHandleList* l = list;
2312 list = l->next();
2313 delete l;
2314 }
2315 }
2316
2317 // Add our OopHandles for later release.
2318 void JavaThread::add_oop_handles_for_release() {
2319 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2320 OopHandleList* new_head = new OopHandleList(_oop_handle_list);
2321 new_head->add(_threadObj);
2322 new_head->add(_vthread);
2323 new_head->add(_jvmti_vthread);
2324 new_head->add(_scopedValueCache);
2325 _oop_handle_list = new_head;
2326 Service_lock->notify_all();
2327 }
2328
2329 #if INCLUDE_JFR
2330 void JavaThread::set_last_freeze_fail_result(freeze_result result) {
2331 assert(result != freeze_ok, "sanity check");
2332 _last_freeze_fail_result = result;
2333 _last_freeze_fail_time = Ticks::now();
2334 }
2335
2336 // Post jdk.VirtualThreadPinned event
2337 void JavaThread::post_vthread_pinned_event(EventVirtualThreadPinned* event, const char* op, freeze_result result) {
2338 assert(result != freeze_ok, "sanity check");
2339 if (event->should_commit()) {
2340 char reason[256];
2341 if (class_to_be_initialized() != nullptr) {
2342 ResourceMark rm(this);
2343 jio_snprintf(reason, sizeof reason, "Waited for initialization of %s by another thread",
2344 class_to_be_initialized()->external_name());
2345 event->set_pinnedReason(reason);
2346 } else if (class_being_initialized() != nullptr) {
2347 ResourceMark rm(this);
2348 jio_snprintf(reason, sizeof(reason), "VM call to %s.<clinit> on stack",
2349 class_being_initialized()->external_name());
2350 event->set_pinnedReason(reason);
2351 } else if (result == freeze_pinned_native) {
2352 event->set_pinnedReason("Native or VM frame on stack");
2353 } else {
2354 jio_snprintf(reason, sizeof(reason), "Freeze or preempt failed (%d)", result);
2355 event->set_pinnedReason(reason);
2356 }
2357 event->set_blockingOperation(op);
2358 event->set_carrierThread(JFR_JVM_THREAD_ID(this));
2359 event->commit();
2360 }
2361 }
2362 #endif