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