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