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/threadCritical.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/vframeArray.hpp"
93 #include "runtime/vframe_hp.hpp"
94 #include "runtime/vmThread.hpp"
95 #include "runtime/vmOperations.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 { \
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(nullptr),
427 _vm_result_2(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 _do_not_unlock_if_synchronized(false),
449 #if INCLUDE_JVMTI
450 _carrier_thread_suspended(false),
451 _is_in_VTMS_transition(false),
452 _is_disable_suspend(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 _can_call_java(true),
497
498 _preempt_alternate_return(nullptr),
499 _preemption_cancelled(false),
500 _pending_interrupted_exception(false),
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) || (CountBytecodesPerThread && log_is_enabled(Info, init))) {
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 if (bc_counter_value() > 0) {
1011 log_info(init)("Thread '%s': " JLONG_FORMAT " bytecodes executed (during clinit: " JLONG_FORMAT ")",
1012 thread_name, bc_counter_value(), clinit_bc_counter_value());
1013 }
1014
1015 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread.
1016 // We call BarrierSet::barrier_set()->on_thread_detach() here so no touching of oops after this point.
1017 Threads::remove(this, daemon);
1018
1019 if (log_is_enabled(Debug, os, thread, timer)) {
1020 _timer_exit_phase4.stop();
1021 log_debug(os, thread, timer)("name='%s'"
1022 ", exit-phase1=" JLONG_FORMAT
1023 ", exit-phase2=" JLONG_FORMAT
1024 ", exit-phase3=" JLONG_FORMAT
1025 ", exit-phase4=" JLONG_FORMAT,
1026 thread_name,
1027 _timer_exit_phase1.milliseconds(),
1028 _timer_exit_phase2.milliseconds(),
1029 _timer_exit_phase3.milliseconds(),
1030 _timer_exit_phase4.milliseconds());
1031 os::free(thread_name);
1032 }
1033 }
1034
1035 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
1036 if (active_handles() != nullptr) {
1037 JNIHandleBlock* block = active_handles();
1038 set_active_handles(nullptr);
1039 JNIHandleBlock::release_block(block);
1040 }
1041
1042 if (free_handle_block() != nullptr) {
1043 JNIHandleBlock* block = free_handle_block();
1044 set_free_handle_block(nullptr);
1045 JNIHandleBlock::release_block(block);
1046 }
1047
1048 // These have to be removed while this is still a valid thread.
1049 _stack_overflow_state.remove_stack_guard_pages();
1050
1051 if (UseTLAB) {
1052 tlab().retire();
1053 }
1054
1055 Threads::remove(this, is_daemon);
1056 }
1057
1058 JavaThread* JavaThread::active() {
1059 Thread* thread = Thread::current();
1060 if (thread->is_Java_thread()) {
1061 return JavaThread::cast(thread);
1062 } else {
1063 assert(thread->is_VM_thread(), "this must be a vm thread");
1064 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1065 JavaThread *ret = op == nullptr ? nullptr : JavaThread::cast(op->calling_thread());
1066 return ret;
1067 }
1068 }
1069
1070 bool JavaThread::is_lock_owned(address adr) const {
1071 assert(LockingMode != LM_LIGHTWEIGHT, "should not be called with new lightweight locking");
1072 return is_in_full_stack(adr);
1073 }
1074
1075 oop JavaThread::exception_oop() const {
1076 return Atomic::load(&_exception_oop);
1077 }
1078
1079 void JavaThread::set_exception_oop(oop o) {
1080 Atomic::store(&_exception_oop, o);
1081 }
1082
1083 void JavaThread::handle_special_runtime_exit_condition() {
1084 if (is_obj_deopt_suspend()) {
1085 frame_anchor()->make_walkable();
1086 wait_for_object_deoptimization();
1087 }
1088 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
1089 }
1090
1091
1092 // Asynchronous exceptions support
1093 //
1094 void JavaThread::handle_async_exception(oop java_throwable) {
1095 assert(java_throwable != nullptr, "should have an _async_exception to throw");
1096 assert(!is_at_poll_safepoint(), "should have never called this method");
1097
1098 if (has_last_Java_frame()) {
1099 frame f = last_frame();
1100 if (f.is_runtime_frame()) {
1101 // If the topmost frame is a runtime stub, then we are calling into
1102 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1103 // must deoptimize the caller before continuing, as the compiled exception
1104 // handler table may not be valid.
1105 RegisterMap reg_map(this,
1106 RegisterMap::UpdateMap::skip,
1107 RegisterMap::ProcessFrames::include,
1108 RegisterMap::WalkContinuation::skip);
1109 frame compiled_frame = f.sender(®_map);
1110 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1111 Deoptimization::deoptimize(this, compiled_frame);
1112 }
1113 }
1114 }
1115
1116 // We cannot call Exceptions::_throw(...) here because we cannot block
1117 set_pending_exception(java_throwable, __FILE__, __LINE__);
1118
1119 clear_scopedValueBindings();
1120
1121 LogTarget(Info, exceptions) lt;
1122 if (lt.is_enabled()) {
1123 ResourceMark rm;
1124 LogStream ls(lt);
1125 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1126 if (has_last_Java_frame()) {
1127 frame f = last_frame();
1128 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1129 }
1130 ls.print_cr(" of type: %s", java_throwable->klass()->external_name());
1131 }
1132 }
1133
1134 void JavaThread::install_async_exception(AsyncExceptionHandshake* aeh) {
1135 // Do not throw asynchronous exceptions against the compiler thread
1136 // or if the thread is already exiting.
1137 if (!can_call_java() || is_exiting()) {
1138 delete aeh;
1139 return;
1140 }
1141
1142 oop exception = aeh->exception();
1143 Handshake::execute(aeh, this); // Install asynchronous handshake
1144
1145 ResourceMark rm;
1146 if (log_is_enabled(Info, exceptions)) {
1147 log_info(exceptions)("Pending Async. exception installed of type: %s",
1148 InstanceKlass::cast(exception->klass())->external_name());
1149 }
1150 // for AbortVMOnException flag
1151 Exceptions::debug_check_abort(exception->klass()->external_name());
1152
1153 oop vt_oop = vthread();
1154 if (vt_oop == nullptr || !vt_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1155 // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1156 java_lang_Thread::set_interrupted(threadObj(), true);
1157 this->interrupt();
1158 }
1159 }
1160
1161 class InstallAsyncExceptionHandshake : public HandshakeClosure {
1162 AsyncExceptionHandshake* _aeh;
1163 public:
1164 InstallAsyncExceptionHandshake(AsyncExceptionHandshake* aeh) :
1165 HandshakeClosure("InstallAsyncException"), _aeh(aeh) {}
1166 ~InstallAsyncExceptionHandshake() {
1167 // If InstallAsyncExceptionHandshake was never executed we need to clean up _aeh.
1168 delete _aeh;
1169 }
1170 void do_thread(Thread* thr) {
1171 JavaThread* target = JavaThread::cast(thr);
1172 target->install_async_exception(_aeh);
1173 _aeh = nullptr;
1174 }
1175 };
1176
1177 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
1178 OopHandle e(Universe::vm_global(), java_throwable);
1179 InstallAsyncExceptionHandshake iaeh(new AsyncExceptionHandshake(e));
1180 Handshake::execute(&iaeh, target);
1181 }
1182
1183 #if INCLUDE_JVMTI
1184 void JavaThread::set_is_in_VTMS_transition(bool val) {
1185 assert(is_in_VTMS_transition() != val, "already %s transition", val ? "inside" : "outside");
1186 _is_in_VTMS_transition = val;
1187 }
1188
1189 #ifdef ASSERT
1190 void JavaThread::set_is_VTMS_transition_disabler(bool val) {
1191 _is_VTMS_transition_disabler = val;
1192 }
1193 #endif
1194 #endif
1195
1196 // External suspension mechanism.
1197 //
1198 // Guarantees on return (for a valid target thread):
1199 // - Target thread will not execute any new bytecode.
1200 // - Target thread will not enter any new monitors.
1201 //
1202 bool JavaThread::java_suspend() {
1203 #if INCLUDE_JVMTI
1204 // Suspending a JavaThread in VTMS transition or disabling VTMS transitions can cause deadlocks.
1205 assert(!is_in_VTMS_transition(), "no suspend allowed in VTMS transition");
1206 assert(!is_VTMS_transition_disabler(), "no suspend allowed for VTMS transition disablers");
1207 #endif
1208
1209 guarantee(Thread::is_JavaThread_protected(/* target */ this),
1210 "target JavaThread is not protected in calling context.");
1211 return this->handshake_state()->suspend();
1212 }
1213
1214 bool JavaThread::java_resume() {
1215 guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1216 "missing ThreadsListHandle in calling context.");
1217 return this->handshake_state()->resume();
1218 }
1219
1220 // Wait for another thread to perform object reallocation and relocking on behalf of
1221 // this thread. The current thread is required to change to _thread_blocked in order
1222 // to be seen to be safepoint/handshake safe whilst suspended and only after becoming
1223 // handshake safe, the other thread can complete the handshake used to synchronize
1224 // with this thread and then perform the reallocation and relocking.
1225 // See EscapeBarrier::sync_and_suspend_*()
1226
1227 void JavaThread::wait_for_object_deoptimization() {
1228 assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1229 assert(this == Thread::current(), "invariant");
1230
1231 bool spin_wait = os::is_MP();
1232 do {
1233 ThreadBlockInVM tbivm(this, true /* allow_suspend */);
1234 // Wait for object deoptimization if requested.
1235 if (spin_wait) {
1236 // A single deoptimization is typically very short. Microbenchmarks
1237 // showed 5% better performance when spinning.
1238 const uint spin_limit = 10 * SpinYield::default_spin_limit;
1239 SpinYield spin(spin_limit);
1240 for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1241 spin.wait();
1242 }
1243 // Spin just once
1244 spin_wait = false;
1245 } else {
1246 MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1247 if (is_obj_deopt_suspend()) {
1248 ml.wait();
1249 }
1250 }
1251 // A handshake for obj. deoptimization suspend could have been processed so
1252 // we must check after processing.
1253 } while (is_obj_deopt_suspend());
1254 }
1255
1256 #ifdef ASSERT
1257 // Verify the JavaThread has not yet been published in the Threads::list, and
1258 // hence doesn't need protection from concurrent access at this stage.
1259 void JavaThread::verify_not_published() {
1260 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1261 // since an unpublished JavaThread doesn't participate in the
1262 // Thread-SMR protocol for keeping a ThreadsList alive.
1263 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1264 }
1265 #endif
1266
1267 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1268 // pending, when _suspend_flags is non-zero or when we need to process a stack
1269 // watermark. Also check for pending async exceptions (except unsafe access error).
1270 // Note only the native==>Java barriers can call this function when thread state
1271 // is _thread_in_native_trans.
1272 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1273 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1274 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1275
1276 thread->set_thread_state(_thread_in_vm);
1277
1278 // Enable WXWrite: called directly from interpreter native wrapper.
1279 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1280
1281 SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
1282
1283 // After returning from native, it could be that the stack frames are not
1284 // yet safe to use. We catch such situations in the subsequent stack watermark
1285 // barrier, which will trap unsafe stack frames.
1286 StackWatermarkSet::before_unwind(thread);
1287 }
1288
1289 #ifndef PRODUCT
1290 // Deoptimization
1291 // Function for testing deoptimization
1292 void JavaThread::deoptimize() {
1293 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1294 bool deopt = false; // Dump stack only if a deopt actually happens.
1295 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1296 // Iterate over all frames in the thread and deoptimize
1297 for (; !fst.is_done(); fst.next()) {
1298 if (fst.current()->can_be_deoptimized()) {
1299
1300 if (only_at) {
1301 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
1302 // consists of comma or carriage return separated numbers so
1303 // search for the current bci in that string.
1304 address pc = fst.current()->pc();
1305 nmethod* nm = fst.current()->cb()->as_nmethod();
1306 ScopeDesc* sd = nm->scope_desc_at(pc);
1307 char buffer[8];
1308 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1309 size_t len = strlen(buffer);
1310 const char * found = strstr(DeoptimizeOnlyAt, buffer);
1311 while (found != nullptr) {
1312 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1313 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1314 // Check that the bci found is bracketed by terminators.
1315 break;
1316 }
1317 found = strstr(found + 1, buffer);
1318 }
1319 if (!found) {
1320 continue;
1321 }
1322 }
1323
1324 if (DebugDeoptimization && !deopt) {
1325 deopt = true; // One-time only print before deopt
1326 tty->print_cr("[BEFORE Deoptimization]");
1327 trace_frames();
1328 trace_stack();
1329 }
1330 Deoptimization::deoptimize(this, *fst.current());
1331 }
1332 }
1333
1334 if (DebugDeoptimization && deopt) {
1335 tty->print_cr("[AFTER Deoptimization]");
1336 trace_frames();
1337 }
1338 }
1339
1340
1341 // Make zombies
1342 void JavaThread::make_zombies() {
1343 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1344 if (fst.current()->can_be_deoptimized()) {
1345 // it is a Java nmethod
1346 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1347 assert(nm != nullptr, "did not find nmethod");
1348 nm->make_not_entrant("zombie");
1349 }
1350 }
1351 }
1352 #endif // PRODUCT
1353
1354
1355 void JavaThread::deoptimize_marked_methods() {
1356 if (!has_last_Java_frame()) return;
1357 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1358 for (; !fst.is_done(); fst.next()) {
1359 if (fst.current()->should_be_deoptimized()) {
1360 Deoptimization::deoptimize(this, *fst.current());
1361 }
1362 }
1363 }
1364
1365 #ifdef ASSERT
1366 void JavaThread::verify_frame_info() {
1367 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1368 (has_last_Java_frame() && java_call_counter() > 0),
1369 "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1370 has_last_Java_frame() ? "true" : "false", java_call_counter());
1371 }
1372 #endif
1373
1374 // Push on a new block of JNI handles.
1375 void JavaThread::push_jni_handle_block() {
1376 // Allocate a new block for JNI handles.
1377 // Inlined code from jni_PushLocalFrame()
1378 JNIHandleBlock* old_handles = active_handles();
1379 JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this);
1380 assert(old_handles != nullptr && new_handles != nullptr, "should not be null");
1381 new_handles->set_pop_frame_link(old_handles); // make sure java handles get gc'd.
1382 set_active_handles(new_handles);
1383 }
1384
1385 // Pop off the current block of JNI handles.
1386 void JavaThread::pop_jni_handle_block() {
1387 // Release our JNI handle block
1388 JNIHandleBlock* old_handles = active_handles();
1389 JNIHandleBlock* new_handles = old_handles->pop_frame_link();
1390 assert(new_handles != nullptr, "should never set active handles to null");
1391 set_active_handles(new_handles);
1392 old_handles->set_pop_frame_link(nullptr);
1393 JNIHandleBlock::release_block(old_handles, this);
1394 }
1395
1396 void JavaThread::oops_do_no_frames(OopClosure* f, NMethodClosure* cf) {
1397 // Verify that the deferred card marks have been flushed.
1398 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1399
1400 // Traverse the GCHandles
1401 Thread::oops_do_no_frames(f, cf);
1402
1403 if (active_handles() != nullptr) {
1404 active_handles()->oops_do(f);
1405 }
1406
1407 DEBUG_ONLY(verify_frame_info();)
1408
1409 assert(vframe_array_head() == nullptr, "deopt in progress at a safepoint!");
1410 // If we have deferred set_locals there might be oops waiting to be
1411 // written
1412 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1413 if (list != nullptr) {
1414 for (int i = 0; i < list->length(); i++) {
1415 list->at(i)->oops_do(f);
1416 }
1417 }
1418
1419 // Traverse instance variables at the end since the GC may be moving things
1420 // around using this function
1421 f->do_oop((oop*) &_vm_result);
1422 f->do_oop((oop*) &_exception_oop);
1423 #if INCLUDE_JVMCI
1424 f->do_oop((oop*) &_jvmci_reserved_oop0);
1425
1426 if (_live_nmethod != nullptr && cf != nullptr) {
1427 cf->do_nmethod(_live_nmethod);
1428 }
1429 #endif
1430
1431 if (jvmti_thread_state() != nullptr) {
1432 jvmti_thread_state()->oops_do(f, cf);
1433 }
1434
1435 // The continuation oops are really on the stack. But there is typically at most
1436 // one of those per thread, so we handle them here in the oops_do_no_frames part
1437 // so that we don't have to sprinkle as many stack watermark checks where these
1438 // oops are used. We just need to make sure the thread has started processing.
1439 ContinuationEntry* entry = _cont_entry;
1440 while (entry != nullptr) {
1441 f->do_oop((oop*)entry->cont_addr());
1442 f->do_oop((oop*)entry->chunk_addr());
1443 entry = entry->parent();
1444 }
1445
1446 if (LockingMode == LM_LIGHTWEIGHT) {
1447 lock_stack().oops_do(f);
1448 }
1449 }
1450
1451 void JavaThread::oops_do_frames(OopClosure* f, NMethodClosure* cf) {
1452 if (!has_last_Java_frame()) {
1453 return;
1454 }
1455 // Finish any pending lazy GC activity for the frames
1456 StackWatermarkSet::finish_processing(this, nullptr /* context */, StackWatermarkKind::gc);
1457 // Traverse the execution stack
1458 for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1459 fst.current()->oops_do(f, cf, fst.register_map());
1460 }
1461 }
1462
1463 #ifdef ASSERT
1464 void JavaThread::verify_states_for_handshake() {
1465 // This checks that the thread has a correct frame state during a handshake.
1466 verify_frame_info();
1467 }
1468 #endif
1469
1470 void JavaThread::nmethods_do(NMethodClosure* cf) {
1471 DEBUG_ONLY(verify_frame_info();)
1472 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current());)
1473
1474 if (has_last_Java_frame()) {
1475 // Traverse the execution stack
1476 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1477 fst.current()->nmethod_do(cf);
1478 }
1479 }
1480
1481 if (jvmti_thread_state() != nullptr) {
1482 jvmti_thread_state()->nmethods_do(cf);
1483 }
1484
1485 #if INCLUDE_JVMCI
1486 if (_live_nmethod != nullptr) {
1487 cf->do_nmethod(_live_nmethod);
1488 }
1489 #endif
1490 }
1491
1492 void JavaThread::metadata_do(MetadataClosure* f) {
1493 if (has_last_Java_frame()) {
1494 // Traverse the execution stack to call f() on the methods in the stack
1495 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1496 fst.current()->metadata_do(f);
1497 }
1498 } else if (is_Compiler_thread()) {
1499 // need to walk ciMetadata in current compile tasks to keep alive.
1500 CompilerThread* ct = (CompilerThread*)this;
1501 if (ct->env() != nullptr) {
1502 ct->env()->metadata_do(f);
1503 }
1504 CompileTask* task = ct->task();
1505 if (task != nullptr) {
1506 task->metadata_do(f);
1507 }
1508 }
1509 }
1510
1511 // Printing
1512 static const char* _get_thread_state_name(JavaThreadState _thread_state) {
1513 switch (_thread_state) {
1514 case _thread_uninitialized: return "_thread_uninitialized";
1515 case _thread_new: return "_thread_new";
1516 case _thread_new_trans: return "_thread_new_trans";
1517 case _thread_in_native: return "_thread_in_native";
1518 case _thread_in_native_trans: return "_thread_in_native_trans";
1519 case _thread_in_vm: return "_thread_in_vm";
1520 case _thread_in_vm_trans: return "_thread_in_vm_trans";
1521 case _thread_in_Java: return "_thread_in_Java";
1522 case _thread_in_Java_trans: return "_thread_in_Java_trans";
1523 case _thread_blocked: return "_thread_blocked";
1524 case _thread_blocked_trans: return "_thread_blocked_trans";
1525 default: return "unknown thread state";
1526 }
1527 }
1528
1529 void JavaThread::print_thread_state_on(outputStream *st) const {
1530 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
1531 }
1532
1533 // Called by Threads::print() for VM_PrintThreads operation
1534 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
1535 st->print_raw("\"");
1536 st->print_raw(name());
1537 st->print_raw("\" ");
1538 oop thread_oop = threadObj();
1539 if (thread_oop != nullptr) {
1540 st->print("#" INT64_FORMAT " [%ld] ", (int64_t)java_lang_Thread::thread_id(thread_oop), (long) osthread()->thread_id());
1541 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
1542 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
1543 }
1544 Thread::print_on(st, print_extended_info);
1545 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
1546 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
1547 if (thread_oop != nullptr) {
1548 if (is_vthread_mounted()) {
1549 st->print_cr(" Carrying virtual thread #" INT64_FORMAT, java_lang_Thread::thread_id(vthread()));
1550 } else {
1551 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
1552 }
1553 }
1554 #ifndef PRODUCT
1555 _safepoint_state->print_on(st);
1556 #endif // PRODUCT
1557 if (is_Compiler_thread()) {
1558 CompileTask *task = ((CompilerThread*)this)->task();
1559 if (task != nullptr) {
1560 st->print(" Compiling: ");
1561 task->print(st, nullptr, true, false);
1562 } else {
1563 st->print(" No compile task");
1564 }
1565 st->cr();
1566 }
1567 }
1568
1569 void JavaThread::print() const { print_on(tty); }
1570
1571 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
1572 st->print("%s", get_thread_name_string(buf, buflen));
1573 }
1574
1575 // Called by fatal error handler. The difference between this and
1576 // JavaThread::print() is that we can't grab lock or allocate memory.
1577 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
1578 st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
1579 Thread* current = Thread::current_or_null_safe();
1580 assert(current != nullptr, "cannot be called by a detached thread");
1581 st->fill_to(60);
1582 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1583 // Only access threadObj() if current thread is not a JavaThread
1584 // or if it is a JavaThread that can safely access oops.
1585 oop thread_obj = threadObj();
1586 if (thread_obj != nullptr) {
1587 st->print(java_lang_Thread::is_daemon(thread_obj) ? " daemon" : " ");
1588 }
1589 }
1590 st->print(" [");
1591 st->print("%s", _get_thread_state_name(_thread_state));
1592 if (osthread()) {
1593 st->print(", id=%d", osthread()->thread_id());
1594 }
1595 // Use raw field members for stack base/size as this could be
1596 // called before a thread has run enough to initialize them.
1597 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ") (" PROPERFMT ")",
1598 p2i(_stack_base - _stack_size), p2i(_stack_base),
1599 PROPERFMTARGS(_stack_size));
1600 st->print("]");
1601
1602 ThreadsSMRSupport::print_info_on(this, st);
1603 return;
1604 }
1605
1606
1607 // Verification
1608
1609 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
1610 // ignore if there is no stack
1611 if (!has_last_Java_frame()) return;
1612 // traverse the stack frames. Starts from top frame.
1613 for (StackFrameStream fst(this, true /* update_map */, true /* process_frames */, false /* walk_cont */); !fst.is_done(); fst.next()) {
1614 frame* fr = fst.current();
1615 f(fr, fst.register_map());
1616 }
1617 }
1618
1619 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
1620
1621 void JavaThread::verify() {
1622 // Verify oops in the thread.
1623 oops_do(&VerifyOopClosure::verify_oop, nullptr);
1624
1625 // Verify the stack frames.
1626 frames_do(frame_verify);
1627 }
1628
1629 // CR 6300358 (sub-CR 2137150)
1630 // Most callers of this method assume that it can't return null but a
1631 // thread may not have a name whilst it is in the process of attaching to
1632 // the VM - see CR 6412693, and there are places where a JavaThread can be
1633 // seen prior to having its threadObj set (e.g., JNI attaching threads and
1634 // if vm exit occurs during initialization). These cases can all be accounted
1635 // for such that this method never returns null.
1636 const char* JavaThread::name() const {
1637 if (Thread::is_JavaThread_protected(/* target */ this)) {
1638 // The target JavaThread is protected so get_thread_name_string() is safe:
1639 return get_thread_name_string();
1640 }
1641
1642 // The target JavaThread is not protected so we return the default:
1643 return Thread::name();
1644 }
1645
1646 // Like name() but doesn't include the protection check. This must only be
1647 // called when it is known to be safe, even though the protection check can't tell
1648 // that e.g. when this thread is the init_thread() - see instanceKlass.cpp.
1649 const char* JavaThread::name_raw() const {
1650 return get_thread_name_string();
1651 }
1652
1653 // Returns a non-null representation of this thread's name, or a suitable
1654 // descriptive string if there is no set name.
1655 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
1656 const char* name_str;
1657 #ifdef ASSERT
1658 Thread* current = Thread::current_or_null_safe();
1659 assert(current != nullptr, "cannot be called by a detached thread");
1660 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1661 // Only access threadObj() if current thread is not a JavaThread
1662 // or if it is a JavaThread that can safely access oops.
1663 #endif
1664 oop thread_obj = threadObj();
1665 if (thread_obj != nullptr) {
1666 oop name = java_lang_Thread::name(thread_obj);
1667 if (name != nullptr) {
1668 if (buf == nullptr) {
1669 name_str = java_lang_String::as_utf8_string(name);
1670 } else {
1671 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
1672 }
1673 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
1674 name_str = "<no-name - thread is attaching>";
1675 } else {
1676 name_str = "<un-named>";
1677 }
1678 } else {
1679 name_str = Thread::name();
1680 }
1681 #ifdef ASSERT
1682 } else {
1683 // Current JavaThread has exited...
1684 if (current == this) {
1685 // ... and is asking about itself:
1686 name_str = "<no-name - current JavaThread has exited>";
1687 } else {
1688 // ... and it can't safely determine this JavaThread's name so
1689 // use the default thread name.
1690 name_str = Thread::name();
1691 }
1692 }
1693 #endif
1694 assert(name_str != nullptr, "unexpected null thread name");
1695 return name_str;
1696 }
1697
1698 // Helper to extract the name from the thread oop for logging.
1699 const char* JavaThread::name_for(oop thread_obj) {
1700 assert(thread_obj != nullptr, "precondition");
1701 oop name = java_lang_Thread::name(thread_obj);
1702 const char* name_str;
1703 if (name != nullptr) {
1704 name_str = java_lang_String::as_utf8_string(name);
1705 } else {
1706 name_str = "<un-named>";
1707 }
1708 return name_str;
1709 }
1710
1711 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
1712
1713 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
1714 assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
1715 // Link Java Thread object <-> C++ Thread
1716
1717 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
1718 // and put it into a new Handle. The Handle "thread_oop" can then
1719 // be used to pass the C++ thread object to other methods.
1720
1721 // Set the Java level thread object (jthread) field of the
1722 // new thread (a JavaThread *) to C++ thread object using the
1723 // "thread_oop" handle.
1724
1725 // Set the thread field (a JavaThread *) of the
1726 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
1727
1728 Handle thread_oop(Thread::current(),
1729 JNIHandles::resolve_non_null(jni_thread));
1730 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
1731 "must be initialized");
1732 set_threadOopHandles(thread_oop());
1733 set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
1734
1735 if (prio == NoPriority) {
1736 prio = java_lang_Thread::priority(thread_oop());
1737 assert(prio != NoPriority, "A valid priority should be present");
1738 }
1739
1740 // Push the Java priority down to the native thread; needs Threads_lock
1741 Thread::set_priority(this, prio);
1742
1743 // Add the new thread to the Threads list and set it in motion.
1744 // We must have threads lock in order to call Threads::add.
1745 // It is crucial that we do not block before the thread is
1746 // added to the Threads list for if a GC happens, then the java_thread oop
1747 // will not be visited by GC.
1748 Threads::add(this);
1749 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
1750 // on a ThreadsList. We don't want to wait for the release when the
1751 // Theads_lock is dropped somewhere in the caller since the JavaThread*
1752 // is already visible to JVM/TI via the ThreadsList.
1753 java_lang_Thread::release_set_thread(thread_oop(), this);
1754 }
1755
1756 oop JavaThread::current_park_blocker() {
1757 // Support for JSR-166 locks
1758 oop thread_oop = threadObj();
1759 if (thread_oop != nullptr) {
1760 return java_lang_Thread::park_blocker(thread_oop);
1761 }
1762 return nullptr;
1763 }
1764
1765 // Print current stack trace for checked JNI warnings and JNI fatal errors.
1766 // This is the external format, selecting the platform or vthread
1767 // as applicable, and allowing for a native-only stack.
1768 void JavaThread::print_jni_stack() {
1769 assert(this == JavaThread::current(), "Can't print stack of other threads");
1770 if (!has_last_Java_frame()) {
1771 ResourceMark rm(this);
1772 char* buf = NEW_RESOURCE_ARRAY_RETURN_NULL(char, O_BUFLEN);
1773 if (buf == nullptr) {
1774 tty->print_cr("Unable to print native stack - out of memory");
1775 return;
1776 }
1777 NativeStackPrinter nsp(this);
1778 address lastpc = nullptr;
1779 nsp.print_stack(tty, buf, O_BUFLEN, lastpc,
1780 true /*print_source_info */, -1 /* max stack */ );
1781 } else {
1782 print_active_stack_on(tty);
1783 }
1784 }
1785
1786 void JavaThread::print_stack_on(outputStream* st) {
1787 if (!has_last_Java_frame()) return;
1788
1789 Thread* current_thread = Thread::current();
1790 ResourceMark rm(current_thread);
1791 HandleMark hm(current_thread);
1792
1793 RegisterMap reg_map(this,
1794 RegisterMap::UpdateMap::include,
1795 RegisterMap::ProcessFrames::include,
1796 RegisterMap::WalkContinuation::skip);
1797 vframe* start_vf = platform_thread_last_java_vframe(®_map);
1798 int count = 0;
1799 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1800 if (f->is_java_frame()) {
1801 javaVFrame* jvf = javaVFrame::cast(f);
1802 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1803
1804 // Print out lock information
1805 if (JavaMonitorsInStackTrace) {
1806 jvf->print_lock_info_on(st, count);
1807 }
1808 } else {
1809 // Ignore non-Java frames
1810 }
1811
1812 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1813 count++;
1814 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1815 }
1816 }
1817
1818 void JavaThread::print_vthread_stack_on(outputStream* st) {
1819 assert(is_vthread_mounted(), "Caller should have checked this");
1820 assert(has_last_Java_frame(), "must be");
1821
1822 Thread* current_thread = Thread::current();
1823 ResourceMark rm(current_thread);
1824 HandleMark hm(current_thread);
1825
1826 RegisterMap reg_map(this,
1827 RegisterMap::UpdateMap::include,
1828 RegisterMap::ProcessFrames::include,
1829 RegisterMap::WalkContinuation::include);
1830 ContinuationEntry* cont_entry = last_continuation();
1831 vframe* start_vf = last_java_vframe(®_map);
1832 int count = 0;
1833 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1834 // Watch for end of vthread stack
1835 if (Continuation::is_continuation_enterSpecial(f->fr())) {
1836 assert(cont_entry == Continuation::get_continuation_entry_for_entry_frame(this, f->fr()), "");
1837 if (cont_entry->is_virtual_thread()) {
1838 break;
1839 }
1840 cont_entry = cont_entry->parent();
1841 }
1842 if (f->is_java_frame()) {
1843 javaVFrame* jvf = javaVFrame::cast(f);
1844 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1845
1846 // Print out lock information
1847 if (JavaMonitorsInStackTrace) {
1848 jvf->print_lock_info_on(st, count);
1849 }
1850 } else {
1851 // Ignore non-Java frames
1852 }
1853
1854 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1855 count++;
1856 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1857 }
1858 }
1859
1860 void JavaThread::print_active_stack_on(outputStream* st) {
1861 if (is_vthread_mounted()) {
1862 print_vthread_stack_on(st);
1863 } else {
1864 print_stack_on(st);
1865 }
1866 }
1867
1868 #if INCLUDE_JVMTI
1869 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1870 JvmtiThreadState* JavaThread::rebind_to_jvmti_thread_state_of(oop thread_oop) {
1871 set_jvmti_vthread(thread_oop);
1872
1873 // unbind current JvmtiThreadState from JavaThread
1874 JvmtiThreadState::unbind_from(jvmti_thread_state(), this);
1875
1876 // bind new JvmtiThreadState to JavaThread
1877 JvmtiThreadState::bind_to(java_lang_Thread::jvmti_thread_state(thread_oop), this);
1878
1879 // enable interp_only_mode for virtual or carrier thread if it has pending bit
1880 JvmtiThreadState::process_pending_interp_only(this);
1881
1882 return jvmti_thread_state();
1883 }
1884 #endif
1885
1886 // JVMTI PopFrame support
1887 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
1888 assert(_popframe_preserved_args == nullptr, "should not wipe out old PopFrame preserved arguments");
1889 if (in_bytes(size_in_bytes) != 0) {
1890 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
1891 _popframe_preserved_args_size = in_bytes(size_in_bytes);
1892 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
1893 }
1894 }
1895
1896 void* JavaThread::popframe_preserved_args() {
1897 return _popframe_preserved_args;
1898 }
1899
1900 ByteSize JavaThread::popframe_preserved_args_size() {
1901 return in_ByteSize(_popframe_preserved_args_size);
1902 }
1903
1904 WordSize JavaThread::popframe_preserved_args_size_in_words() {
1905 int sz = in_bytes(popframe_preserved_args_size());
1906 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
1907 return in_WordSize(sz / wordSize);
1908 }
1909
1910 void JavaThread::popframe_free_preserved_args() {
1911 assert(_popframe_preserved_args != nullptr, "should not free PopFrame preserved arguments twice");
1912 FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
1913 _popframe_preserved_args = nullptr;
1914 _popframe_preserved_args_size = 0;
1915 }
1916
1917 #ifndef PRODUCT
1918
1919 void JavaThread::trace_frames() {
1920 tty->print_cr("[Describe stack]");
1921 int frame_no = 1;
1922 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1923 tty->print(" %d. ", frame_no++);
1924 fst.current()->print_value_on(tty);
1925 tty->cr();
1926 }
1927 }
1928
1929 class PrintAndVerifyOopClosure: public OopClosure {
1930 protected:
1931 template <class T> inline void do_oop_work(T* p) {
1932 oop obj = RawAccess<>::oop_load(p);
1933 if (obj == nullptr) return;
1934 tty->print(INTPTR_FORMAT ": ", p2i(p));
1935 if (oopDesc::is_oop_or_null(obj)) {
1936 if (obj->is_objArray()) {
1937 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
1938 } else {
1939 obj->print();
1940 }
1941 } else {
1942 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
1943 }
1944 tty->cr();
1945 }
1946 public:
1947 virtual void do_oop(oop* p) { do_oop_work(p); }
1948 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1949 };
1950
1951 #ifdef ASSERT
1952 // Print or validate the layout of stack frames
1953 void JavaThread::print_frame_layout(int depth, bool validate_only) {
1954 ResourceMark rm;
1955 PreserveExceptionMark pm(this);
1956 FrameValues values;
1957 int frame_no = 0;
1958 for (StackFrameStream fst(this, true, true, true); !fst.is_done(); fst.next()) {
1959 fst.current()->describe(values, ++frame_no, fst.register_map());
1960 if (depth == frame_no) break;
1961 }
1962 Continuation::describe(values);
1963 if (validate_only) {
1964 values.validate();
1965 } else {
1966 tty->print_cr("[Describe stack layout]");
1967 values.print(this);
1968 }
1969 }
1970 #endif
1971
1972 void JavaThread::trace_stack_from(vframe* start_vf) {
1973 ResourceMark rm;
1974 int vframe_no = 1;
1975 for (vframe* f = start_vf; f; f = f->sender()) {
1976 if (f->is_java_frame()) {
1977 javaVFrame::cast(f)->print_activation(vframe_no++);
1978 } else {
1979 f->print();
1980 }
1981 if (vframe_no > StackPrintLimit) {
1982 tty->print_cr("...<more frames>...");
1983 return;
1984 }
1985 }
1986 }
1987
1988
1989 void JavaThread::trace_stack() {
1990 if (!has_last_Java_frame()) return;
1991 Thread* current_thread = Thread::current();
1992 ResourceMark rm(current_thread);
1993 HandleMark hm(current_thread);
1994 RegisterMap reg_map(this,
1995 RegisterMap::UpdateMap::include,
1996 RegisterMap::ProcessFrames::include,
1997 RegisterMap::WalkContinuation::skip);
1998 trace_stack_from(last_java_vframe(®_map));
1999 }
2000
2001
2002 #endif // PRODUCT
2003
2004 // Slow-path increment of the held monitor counts. JNI locking is always
2005 // this slow-path.
2006 void JavaThread::inc_held_monitor_count(intx i, bool jni) {
2007 #ifdef SUPPORT_MONITOR_COUNT
2008
2009 if (LockingMode != LM_LEGACY) {
2010 // Nothing to do. Just do some sanity check.
2011 assert(_held_monitor_count == 0, "counter should not be used");
2012 assert(_jni_monitor_count == 0, "counter should not be used");
2013 return;
2014 }
2015
2016 assert(_held_monitor_count >= 0, "Must always be non-negative: %zd", _held_monitor_count);
2017 _held_monitor_count += i;
2018 if (jni) {
2019 assert(_jni_monitor_count >= 0, "Must always be non-negative: %zd", _jni_monitor_count);
2020 _jni_monitor_count += i;
2021 }
2022 assert(_held_monitor_count >= _jni_monitor_count, "Monitor count discrepancy detected - held count "
2023 "%zd is less than JNI count %zd", _held_monitor_count, _jni_monitor_count);
2024 #endif // SUPPORT_MONITOR_COUNT
2025 }
2026
2027 // Slow-path decrement of the held monitor counts. JNI unlocking is always
2028 // this slow-path.
2029 void JavaThread::dec_held_monitor_count(intx i, bool jni) {
2030 #ifdef SUPPORT_MONITOR_COUNT
2031
2032 if (LockingMode != LM_LEGACY) {
2033 // Nothing to do. Just do some sanity check.
2034 assert(_held_monitor_count == 0, "counter should not be used");
2035 assert(_jni_monitor_count == 0, "counter should not be used");
2036 return;
2037 }
2038
2039 _held_monitor_count -= i;
2040 assert(_held_monitor_count >= 0, "Must always be non-negative: %zd", _held_monitor_count);
2041 if (jni) {
2042 _jni_monitor_count -= i;
2043 assert(_jni_monitor_count >= 0, "Must always be non-negative: %zd", _jni_monitor_count);
2044 }
2045 // When a thread is detaching with still owned JNI monitors, the logic that releases
2046 // the monitors doesn't know to set the "jni" flag and so the counts can get out of sync.
2047 // So we skip this assert if the thread is exiting. Once all monitors are unlocked the
2048 // JNI count is directly set to zero.
2049 assert(_held_monitor_count >= _jni_monitor_count || is_exiting(), "Monitor count discrepancy detected - held count "
2050 "%zd is less than JNI count %zd", _held_monitor_count, _jni_monitor_count);
2051 #endif // SUPPORT_MONITOR_COUNT
2052 }
2053
2054 frame JavaThread::vthread_last_frame() {
2055 assert (is_vthread_mounted(), "Virtual thread not mounted");
2056 return last_frame();
2057 }
2058
2059 frame JavaThread::carrier_last_frame(RegisterMap* reg_map) {
2060 const ContinuationEntry* entry = vthread_continuation();
2061 guarantee (entry != nullptr, "Not a carrier thread");
2062 frame f = entry->to_frame();
2063 if (reg_map->process_frames()) {
2064 entry->flush_stack_processing(this);
2065 }
2066 entry->update_register_map(reg_map);
2067 return f.sender(reg_map);
2068 }
2069
2070 frame JavaThread::platform_thread_last_frame(RegisterMap* reg_map) {
2071 return is_vthread_mounted() ? carrier_last_frame(reg_map) : last_frame();
2072 }
2073
2074 javaVFrame* JavaThread::last_java_vframe(const frame f, RegisterMap *reg_map) {
2075 assert(reg_map != nullptr, "a map must be given");
2076 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
2077 if (vf->is_java_frame()) return javaVFrame::cast(vf);
2078 }
2079 return nullptr;
2080 }
2081
2082 Klass* JavaThread::security_get_caller_class(int depth) {
2083 ResetNoHandleMark rnhm;
2084 HandleMark hm(Thread::current());
2085
2086 vframeStream vfst(this);
2087 vfst.security_get_caller_frame(depth);
2088 if (!vfst.at_end()) {
2089 return vfst.method()->method_holder();
2090 }
2091 return nullptr;
2092 }
2093
2094 // Internal convenience function for millisecond resolution sleeps.
2095 bool JavaThread::sleep(jlong millis) {
2096 jlong nanos;
2097 if (millis > max_jlong / NANOUNITS_PER_MILLIUNIT) {
2098 // Conversion to nanos would overflow, saturate at max
2099 nanos = max_jlong;
2100 } else {
2101 nanos = millis * NANOUNITS_PER_MILLIUNIT;
2102 }
2103 return sleep_nanos(nanos);
2104 }
2105
2106 // java.lang.Thread.sleep support
2107 // Returns true if sleep time elapsed as expected, and false
2108 // if the thread was interrupted.
2109 bool JavaThread::sleep_nanos(jlong nanos) {
2110 assert(this == Thread::current(), "thread consistency check");
2111 assert(nanos >= 0, "nanos are in range");
2112
2113 ParkEvent * const slp = this->_SleepEvent;
2114 // Because there can be races with thread interruption sending an unpark()
2115 // to the event, we explicitly reset it here to avoid an immediate return.
2116 // The actual interrupt state will be checked before we park().
2117 slp->reset();
2118 // Thread interruption establishes a happens-before ordering in the
2119 // Java Memory Model, so we need to ensure we synchronize with the
2120 // interrupt state.
2121 OrderAccess::fence();
2122
2123 jlong prevtime = os::javaTimeNanos();
2124
2125 jlong nanos_remaining = nanos;
2126
2127 for (;;) {
2128 // interruption has precedence over timing out
2129 if (this->is_interrupted(true)) {
2130 return false;
2131 }
2132
2133 if (nanos_remaining <= 0) {
2134 return true;
2135 }
2136
2137 {
2138 ThreadBlockInVM tbivm(this);
2139 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
2140 slp->park_nanos(nanos_remaining);
2141 }
2142
2143 // Update elapsed time tracking
2144 jlong newtime = os::javaTimeNanos();
2145 if (newtime - prevtime < 0) {
2146 // time moving backwards, should only happen if no monotonic clock
2147 // not a guarantee() because JVM should not abort on kernel/glibc bugs
2148 assert(false,
2149 "unexpected time moving backwards detected in JavaThread::sleep()");
2150 } else {
2151 nanos_remaining -= (newtime - prevtime);
2152 }
2153 prevtime = newtime;
2154 }
2155 }
2156
2157 // Last thread running calls java.lang.Shutdown.shutdown()
2158 void JavaThread::invoke_shutdown_hooks() {
2159 HandleMark hm(this);
2160
2161 // We could get here with a pending exception, if so clear it now.
2162 if (this->has_pending_exception()) {
2163 this->clear_pending_exception();
2164 }
2165
2166 EXCEPTION_MARK;
2167 Klass* shutdown_klass =
2168 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
2169 THREAD);
2170 if (shutdown_klass != nullptr) {
2171 // SystemDictionary::resolve_or_null will return null if there was
2172 // an exception. If we cannot load the Shutdown class, just don't
2173 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
2174 // won't be run. Note that if a shutdown hook was registered,
2175 // the Shutdown class would have already been loaded
2176 // (Runtime.addShutdownHook will load it).
2177 JavaValue result(T_VOID);
2178 JavaCalls::call_static(&result,
2179 shutdown_klass,
2180 vmSymbols::shutdown_name(),
2181 vmSymbols::void_method_signature(),
2182 THREAD);
2183 }
2184 CLEAR_PENDING_EXCEPTION;
2185 }
2186
2187 #ifndef PRODUCT
2188 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
2189 report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
2190 }
2191 #endif
2192
2193 // Helper function to create the java.lang.Thread object for a
2194 // VM-internal thread. The thread will have the given name, and be
2195 // a member of the "system" ThreadGroup.
2196 Handle JavaThread::create_system_thread_object(const char* name, TRAPS) {
2197 Handle string = java_lang_String::create_from_str(name, CHECK_NH);
2198
2199 // Initialize thread_oop to put it into the system threadGroup.
2200 // This is done by calling the Thread(ThreadGroup group, String name) constructor.
2201 Handle thread_group(THREAD, Universe::system_thread_group());
2202 Handle thread_oop =
2203 JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
2204 vmSymbols::threadgroup_string_void_signature(),
2205 thread_group,
2206 string,
2207 CHECK_NH);
2208
2209 return thread_oop;
2210 }
2211
2212 // Starts the target JavaThread as a daemon of the given priority, and
2213 // bound to the given java.lang.Thread instance.
2214 // The Threads_lock is held for the duration.
2215 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
2216 Handle thread_oop, ThreadPriority prio) {
2217
2218 assert(target->osthread() != nullptr, "target thread is not properly initialized");
2219
2220 MutexLocker mu(current, Threads_lock);
2221
2222 // Initialize the fields of the thread_oop first.
2223 if (prio != NoPriority) {
2224 java_lang_Thread::set_priority(thread_oop(), prio);
2225 // Note: we don't call os::set_priority here. Possibly we should,
2226 // else all threads should call it themselves when they first run.
2227 }
2228
2229 java_lang_Thread::set_daemon(thread_oop());
2230
2231 // Now bind the thread_oop to the target JavaThread.
2232 target->set_threadOopHandles(thread_oop());
2233 target->set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
2234
2235 Threads::add(target); // target is now visible for safepoint/handshake
2236 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
2237 // on a ThreadsList. We don't want to wait for the release when the
2238 // Theads_lock is dropped when the 'mu' destructor is run since the
2239 // JavaThread* is already visible to JVM/TI via the ThreadsList.
2240
2241 assert(java_lang_Thread::thread(thread_oop()) == nullptr, "must not be alive");
2242 java_lang_Thread::release_set_thread(thread_oop(), target); // isAlive == true now
2243 Thread::start(target);
2244 }
2245
2246 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
2247 // At this point it may be possible that no osthread was created for the
2248 // JavaThread due to lack of resources. However, since this must work
2249 // for critical system threads just check and abort if this fails.
2250 if (thread->osthread() == nullptr) {
2251 // This isn't really an OOM condition, but historically this is what
2252 // we report.
2253 vm_exit_during_initialization("java.lang.OutOfMemoryError",
2254 os::native_thread_creation_failed_msg());
2255 }
2256 }
2257
2258 void JavaThread::pretouch_stack() {
2259 // Given an established java thread stack with usable area followed by
2260 // shadow zone and reserved/yellow/red zone, pretouch the usable area ranging
2261 // from the current frame down to the start of the shadow zone.
2262 const address end = _stack_overflow_state.shadow_zone_safe_limit();
2263 if (is_in_full_stack(end)) {
2264 char* p1 = (char*) alloca(1);
2265 address here = (address) &p1;
2266 if (is_in_full_stack(here) && here > end) {
2267 size_t to_alloc = here - end;
2268 char* p2 = (char*) alloca(to_alloc);
2269 log_trace(os, thread)("Pretouching thread stack for %zu: " RANGEFMT ".",
2270 (uintx) osthread()->thread_id(), RANGEFMTARGS(p2, to_alloc));
2271 os::pretouch_memory(p2, p2 + to_alloc,
2272 NOT_AIX(os::vm_page_size()) AIX_ONLY(4096));
2273 }
2274 }
2275 }
2276
2277 // Deferred OopHandle release support.
2278
2279 class OopHandleList : public CHeapObj<mtInternal> {
2280 static const int _count = 4;
2281 OopHandle _handles[_count];
2282 OopHandleList* _next;
2283 int _index;
2284 public:
2285 OopHandleList(OopHandleList* next) : _next(next), _index(0) {}
2286 void add(OopHandle h) {
2287 assert(_index < _count, "too many additions");
2288 _handles[_index++] = h;
2289 }
2290 ~OopHandleList() {
2291 assert(_index == _count, "usage error");
2292 for (int i = 0; i < _index; i++) {
2293 _handles[i].release(JavaThread::thread_oop_storage());
2294 }
2295 }
2296 OopHandleList* next() const { return _next; }
2297 };
2298
2299 OopHandleList* JavaThread::_oop_handle_list = nullptr;
2300
2301 // Called by the ServiceThread to do the work of releasing
2302 // the OopHandles.
2303 void JavaThread::release_oop_handles() {
2304 OopHandleList* list;
2305 {
2306 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2307 list = _oop_handle_list;
2308 _oop_handle_list = nullptr;
2309 }
2310 assert(!SafepointSynchronize::is_at_safepoint(), "cannot be called at a safepoint");
2311
2312 while (list != nullptr) {
2313 OopHandleList* l = list;
2314 list = l->next();
2315 delete l;
2316 }
2317 }
2318
2319 // Add our OopHandles for later release.
2320 void JavaThread::add_oop_handles_for_release() {
2321 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2322 OopHandleList* new_head = new OopHandleList(_oop_handle_list);
2323 new_head->add(_threadObj);
2324 new_head->add(_vthread);
2325 new_head->add(_jvmti_vthread);
2326 new_head->add(_scopedValueCache);
2327 _oop_handle_list = new_head;
2328 Service_lock->notify_all();
2329 }
2330
2331 #if INCLUDE_JFR
2332 void JavaThread::set_last_freeze_fail_result(freeze_result result) {
2333 assert(result != freeze_ok, "sanity check");
2334 _last_freeze_fail_result = result;
2335 _last_freeze_fail_time = Ticks::now();
2336 }
2337
2338 // Post jdk.VirtualThreadPinned event
2339 void JavaThread::post_vthread_pinned_event(EventVirtualThreadPinned* event, const char* op, freeze_result result) {
2340 assert(result != freeze_ok, "sanity check");
2341 if (event->should_commit()) {
2342 char reason[256];
2343 if (class_to_be_initialized() != nullptr) {
2344 ResourceMark rm(this);
2345 jio_snprintf(reason, sizeof reason, "Waited for initialization of %s by another thread",
2346 class_to_be_initialized()->external_name());
2347 event->set_pinnedReason(reason);
2348 } else if (class_being_initialized() != nullptr) {
2349 ResourceMark rm(this);
2350 jio_snprintf(reason, sizeof(reason), "VM call to %s.<clinit> on stack",
2351 class_being_initialized()->external_name());
2352 event->set_pinnedReason(reason);
2353 } else if (result == freeze_pinned_native) {
2354 event->set_pinnedReason("Native or VM frame on stack");
2355 } else {
2356 jio_snprintf(reason, sizeof(reason), "Freeze or preempt failed (%d)", result);
2357 event->set_pinnedReason(reason);
2358 }
2359 event->set_blockingOperation(op);
2360 event->set_carrierThread(JFR_JVM_THREAD_ID(this));
2361 event->commit();
2362 }
2363 }
2364 #endif