1 /*
2 * Copyright (c) 1997, 2025, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2021, Azul Systems, Inc. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "precompiled.hpp"
27 #include "cds/dynamicArchive.hpp"
28 #include "ci/ciEnv.hpp"
29 #include "classfile/javaClasses.inline.hpp"
30 #include "classfile/javaThreadStatus.hpp"
31 #include "classfile/systemDictionary.hpp"
32 #include "classfile/vmClasses.hpp"
33 #include "classfile/vmSymbols.hpp"
34 #include "code/codeCache.hpp"
35 #include "code/scopeDesc.hpp"
36 #include "compiler/compileTask.hpp"
37 #include "compiler/compilerThread.hpp"
38 #include "gc/shared/oopStorage.hpp"
39 #include "gc/shared/oopStorageSet.hpp"
40 #include "gc/shared/tlab_globals.hpp"
41 #include "jfr/jfrEvents.hpp"
42 #include "jvm.h"
43 #include "jvmtifiles/jvmtiEnv.hpp"
44 #include "logging/log.hpp"
45 #include "logging/logAsyncWriter.hpp"
46 #include "logging/logStream.hpp"
47 #include "memory/allocation.inline.hpp"
48 #include "memory/iterator.hpp"
49 #include "memory/universe.hpp"
50 #include "oops/access.inline.hpp"
51 #include "oops/instanceKlass.hpp"
52 #include "oops/klass.inline.hpp"
53 #include "oops/oop.inline.hpp"
54 #include "oops/oopHandle.inline.hpp"
55 #include "oops/verifyOopClosure.hpp"
56 #include "prims/jvm_misc.hpp"
57 #include "prims/jvmtiDeferredUpdates.hpp"
58 #include "prims/jvmtiExport.hpp"
59 #include "prims/jvmtiThreadState.inline.hpp"
60 #include "runtime/atomic.hpp"
61 #include "runtime/continuation.hpp"
62 #include "runtime/continuationEntry.inline.hpp"
63 #include "runtime/continuationHelper.inline.hpp"
64 #include "runtime/deoptimization.hpp"
65 #include "runtime/frame.inline.hpp"
66 #include "runtime/handles.inline.hpp"
67 #include "runtime/handshake.hpp"
68 #include "runtime/interfaceSupport.inline.hpp"
69 #include "runtime/java.hpp"
70 #include "runtime/javaCalls.hpp"
71 #include "runtime/javaThread.inline.hpp"
72 #include "runtime/jniHandles.inline.hpp"
73 #include "runtime/lockStack.inline.hpp"
74 #include "runtime/mutexLocker.hpp"
75 #include "runtime/orderAccess.hpp"
76 #include "runtime/os.inline.hpp"
77 #include "runtime/osThread.hpp"
78 #include "runtime/safepoint.hpp"
79 #include "runtime/safepointMechanism.inline.hpp"
80 #include "runtime/safepointVerifiers.hpp"
81 #include "runtime/serviceThread.hpp"
82 #include "runtime/stackFrameStream.inline.hpp"
83 #include "runtime/stackWatermarkSet.hpp"
84 #include "runtime/synchronizer.hpp"
85 #include "runtime/threadCritical.hpp"
86 #include "runtime/threadIdentifier.hpp"
87 #include "runtime/threadSMR.inline.hpp"
88 #include "runtime/threadStatisticalInfo.hpp"
89 #include "runtime/threadWXSetters.inline.hpp"
90 #include "runtime/timer.hpp"
91 #include "runtime/timerTrace.hpp"
92 #include "runtime/vframe.inline.hpp"
93 #include "runtime/vframeArray.hpp"
94 #include "runtime/vframe_hp.hpp"
95 #include "runtime/vmThread.hpp"
96 #include "runtime/vmOperations.hpp"
97 #include "services/threadService.hpp"
98 #include "utilities/copy.hpp"
99 #include "utilities/defaultStream.hpp"
100 #include "utilities/dtrace.hpp"
101 #include "utilities/events.hpp"
102 #include "utilities/macros.hpp"
103 #include "utilities/nativeStackPrinter.hpp"
104 #include "utilities/preserveException.hpp"
105 #include "utilities/spinYield.hpp"
106 #include "utilities/vmError.hpp"
107 #if INCLUDE_JVMCI
108 #include "jvmci/jvmci.hpp"
109 #include "jvmci/jvmciEnv.hpp"
110 #endif
111 #if INCLUDE_JFR
112 #include "jfr/jfr.hpp"
113 #endif
114
115 // Set by os layer.
116 size_t JavaThread::_stack_size_at_create = 0;
117
118 #ifdef DTRACE_ENABLED
119
120 // Only bother with this argument setup if dtrace is available
121
122 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
123 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
124
125 #define DTRACE_THREAD_PROBE(probe, javathread) \
126 { \
127 ResourceMark rm(this); \
128 int len = 0; \
129 const char* name = (javathread)->name(); \
130 len = strlen(name); \
131 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
132 (char *) name, len, \
133 java_lang_Thread::thread_id((javathread)->threadObj()), \
134 (uintptr_t) (javathread)->osthread()->thread_id(), \
135 java_lang_Thread::is_daemon((javathread)->threadObj())); \
136 }
137
138 #else // ndef DTRACE_ENABLED
139
140 #define DTRACE_THREAD_PROBE(probe, javathread)
141
142 #endif // ndef DTRACE_ENABLED
143
144 void JavaThread::smr_delete() {
145 if (_on_thread_list) {
146 ThreadsSMRSupport::smr_delete(this);
147 } else {
148 delete this;
149 }
150 }
151
152 // Initialized by VMThread at vm_global_init
153 OopStorage* JavaThread::_thread_oop_storage = nullptr;
154
155 OopStorage* JavaThread::thread_oop_storage() {
156 assert(_thread_oop_storage != nullptr, "not yet initialized");
157 return _thread_oop_storage;
158 }
159
160 void JavaThread::set_threadOopHandles(oop p) {
161 assert(_thread_oop_storage != nullptr, "not yet initialized");
162 _threadObj = OopHandle(_thread_oop_storage, p);
163 _vthread = OopHandle(_thread_oop_storage, p);
164 _jvmti_vthread = OopHandle(_thread_oop_storage, p->is_a(vmClasses::BoundVirtualThread_klass()) ? p : nullptr);
165 _scopedValueCache = OopHandle(_thread_oop_storage, nullptr);
166 }
167
168 oop JavaThread::threadObj() const {
169 // Ideally we would verify the current thread is oop_safe when this is called, but as we can
170 // be called from a signal handler we would have to use Thread::current_or_null_safe(). That
171 // has overhead and also interacts poorly with GetLastError on Windows due to the use of TLS.
172 // Instead callers must verify oop safe access.
173 return _threadObj.resolve();
174 }
175
176 oop JavaThread::vthread() const {
177 return _vthread.resolve();
178 }
179
180 void JavaThread::set_vthread(oop p) {
181 assert(_thread_oop_storage != nullptr, "not yet initialized");
182 _vthread.replace(p);
183 }
184
185 oop JavaThread::jvmti_vthread() const {
186 return _jvmti_vthread.resolve();
187 }
188
189 void JavaThread::set_jvmti_vthread(oop p) {
190 assert(_thread_oop_storage != nullptr, "not yet initialized");
191 _jvmti_vthread.replace(p);
192 }
193
194 // If there is a virtual thread mounted then return vthread() oop.
195 // Otherwise, return threadObj().
196 oop JavaThread::vthread_or_thread() const {
197 oop result = vthread();
198 if (result == nullptr) {
199 result = threadObj();
200 }
201 return result;
202 }
203
204 oop JavaThread::scopedValueCache() const {
205 return _scopedValueCache.resolve();
206 }
207
208 void JavaThread::set_scopedValueCache(oop p) {
209 if (!_scopedValueCache.is_empty()) { // i.e. if the OopHandle has been allocated
210 _scopedValueCache.replace(p);
211 } else {
212 assert(p == nullptr, "not yet initialized");
213 }
214 }
215
216 void JavaThread::clear_scopedValueBindings() {
217 set_scopedValueCache(nullptr);
218 oop vthread_oop = vthread();
219 // vthread may be null here if we get a VM error during startup,
220 // before the java.lang.Thread instance has been created.
221 if (vthread_oop != nullptr) {
222 java_lang_Thread::clear_scopedValueBindings(vthread_oop);
223 }
224 }
225
226 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
227 bool daemon, TRAPS) {
228 assert(thread_group.not_null(), "thread group should be specified");
229 assert(threadObj() == nullptr, "should only create Java thread object once");
230
231 InstanceKlass* ik = vmClasses::Thread_klass();
232 assert(ik->is_initialized(), "must be");
233 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
234
235 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
236 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
237 // constructor calls Thread.current(), which must be set here.
238 java_lang_Thread::set_thread(thread_oop(), this);
239 set_threadOopHandles(thread_oop());
240 // Set the _monitor_owner_id to the next thread_id temporarily while initialization runs.
241 set_monitor_owner_id(ThreadIdentifier::next());
242
243 JavaValue result(T_VOID);
244 if (thread_name != nullptr) {
245 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
246 // Thread gets assigned specified name and null target
247 JavaCalls::call_special(&result,
248 thread_oop,
249 ik,
250 vmSymbols::object_initializer_name(),
251 vmSymbols::threadgroup_string_void_signature(),
252 thread_group,
253 name,
254 CHECK);
255 } else {
256 // Thread gets assigned name "Thread-nnn" and null target
257 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
258 JavaCalls::call_special(&result,
259 thread_oop,
260 ik,
261 vmSymbols::object_initializer_name(),
262 vmSymbols::threadgroup_runnable_void_signature(),
263 thread_group,
264 Handle(),
265 CHECK);
266 }
267 // Update the _monitor_owner_id with the tid value.
268 set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
269
270 os::set_priority(this, NormPriority);
271
272 if (daemon) {
273 java_lang_Thread::set_daemon(thread_oop());
274 }
275 }
276
277 // ======= JavaThread ========
278
279 #if INCLUDE_JVMCI
280
281 jlong* JavaThread::_jvmci_old_thread_counters;
282
283 static bool jvmci_counters_include(JavaThread* thread) {
284 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
285 }
286
287 void JavaThread::collect_counters(jlong* array, int length) {
288 assert(length == JVMCICounterSize, "wrong value");
289 for (int i = 0; i < length; i++) {
290 array[i] = _jvmci_old_thread_counters[i];
291 }
292 for (JavaThread* tp : ThreadsListHandle()) {
293 if (jvmci_counters_include(tp)) {
294 for (int i = 0; i < length; i++) {
295 array[i] += tp->_jvmci_counters[i];
296 }
297 }
298 }
299 }
300
301 // Attempt to enlarge the array for per thread counters.
302 static jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
303 jlong* new_counters = NEW_C_HEAP_ARRAY_RETURN_NULL(jlong, new_size, mtJVMCI);
304 if (new_counters == nullptr) {
305 return nullptr;
306 }
307 if (old_counters == nullptr) {
308 old_counters = new_counters;
309 memset(old_counters, 0, sizeof(jlong) * new_size);
310 } else {
311 for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
312 new_counters[i] = old_counters[i];
313 }
314 if (new_size > current_size) {
315 memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
316 }
317 FREE_C_HEAP_ARRAY(jlong, old_counters);
318 }
319 return new_counters;
320 }
321
322 // Attempt to enlarge the array for per thread counters.
323 bool JavaThread::resize_counters(int current_size, int new_size) {
324 jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
325 if (new_counters == nullptr) {
326 return false;
327 } else {
328 _jvmci_counters = new_counters;
329 return true;
330 }
331 }
332
333 class VM_JVMCIResizeCounters : public VM_Operation {
334 private:
335 int _new_size;
336 bool _failed;
337
338 public:
339 VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { }
340 VMOp_Type type() const { return VMOp_JVMCIResizeCounters; }
341 bool allow_nested_vm_operations() const { return true; }
342 void doit() {
343 // Resize the old thread counters array
344 jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
345 if (new_counters == nullptr) {
346 _failed = true;
347 return;
348 } else {
349 JavaThread::_jvmci_old_thread_counters = new_counters;
350 }
351
352 // Now resize each threads array
353 for (JavaThread* tp : ThreadsListHandle()) {
354 if (!tp->resize_counters(JVMCICounterSize, _new_size)) {
355 _failed = true;
356 break;
357 }
358 }
359 if (!_failed) {
360 JVMCICounterSize = _new_size;
361 }
362 }
363
364 bool failed() { return _failed; }
365 };
366
367 bool JavaThread::resize_all_jvmci_counters(int new_size) {
368 VM_JVMCIResizeCounters op(new_size);
369 VMThread::execute(&op);
370 return !op.failed();
371 }
372
373 #endif // INCLUDE_JVMCI
374
375 #ifdef ASSERT
376 // Checks safepoint allowed and clears unhandled oops at potential safepoints.
377 void JavaThread::check_possible_safepoint() {
378 if (_no_safepoint_count > 0) {
379 print_owned_locks();
380 assert(false, "Possible safepoint reached by thread that does not allow it");
381 }
382 #ifdef CHECK_UNHANDLED_OOPS
383 // Clear unhandled oops in JavaThreads so we get a crash right away.
384 clear_unhandled_oops();
385 #endif // CHECK_UNHANDLED_OOPS
386
387 // Macos/aarch64 should be in the right state for safepoint (e.g.
388 // deoptimization needs WXWrite). Crashes caused by the wrong state rarely
389 // happens in practice, making such issues hard to find and reproduce.
390 #if defined(__APPLE__) && defined(AARCH64)
391 if (AssertWXAtThreadSync) {
392 assert_wx_state(WXWrite);
393 }
394 #endif
395 }
396
397 void JavaThread::check_for_valid_safepoint_state() {
398 // Don't complain if running a debugging command.
399 if (DebuggingContext::is_enabled()) return;
400
401 // Check NoSafepointVerifier, which is implied by locks taken that can be
402 // shared with the VM thread. This makes sure that no locks with allow_vm_block
403 // are held.
404 check_possible_safepoint();
405
406 if (thread_state() != _thread_in_vm) {
407 fatal("LEAF method calling lock?");
408 }
409
410 if (GCALotAtAllSafepoints) {
411 // We could enter a safepoint here and thus have a gc
412 InterfaceSupport::check_gc_alot();
413 }
414 }
415 #endif // ASSERT
416
417 // A JavaThread is a normal Java thread
418
419 JavaThread::JavaThread(MemTag mem_tag) :
420 Thread(mem_tag),
421 // Initialize fields
422 _on_thread_list(false),
423 DEBUG_ONLY(_java_call_counter(0) COMMA)
424 _entry_point(nullptr),
425 _deopt_mark(nullptr),
426 _deopt_nmethod(nullptr),
427 _vframe_array_head(nullptr),
428 _vframe_array_last(nullptr),
429 _jvmti_deferred_updates(nullptr),
430 _callee_target(nullptr),
431 _vm_result(nullptr),
432 _vm_result_2(nullptr),
433
434 _current_pending_monitor(nullptr),
435 _current_pending_monitor_is_from_java(true),
436 _current_waiting_monitor(nullptr),
437 _active_handles(nullptr),
438 _free_handle_block(nullptr),
439 _monitor_owner_id(0),
440
441 _suspend_flags(0),
442
443 _thread_state(_thread_new),
444 _saved_exception_pc(nullptr),
445 #ifdef ASSERT
446 _no_safepoint_count(0),
447 _visited_for_critical_count(false),
448 #endif
449
450 _terminated(_not_terminated),
451 _in_deopt_handler(0),
452 _doing_unsafe_access(false),
453 _do_not_unlock_if_synchronized(false),
454 #if INCLUDE_JVMTI
455 _carrier_thread_suspended(false),
456 _is_in_VTMS_transition(false),
457 _is_disable_suspend(false),
458 _VTMS_transition_mark(false),
459 _on_monitor_waited_event(false),
460 _contended_entered_monitor(nullptr),
461 #ifdef ASSERT
462 _is_VTMS_transition_disabler(false),
463 #endif
464 #endif
465 _jni_attach_state(_not_attaching_via_jni),
466 _is_in_internal_oome_mark(false),
467 #if INCLUDE_JVMCI
468 _pending_deoptimization(-1),
469 _pending_monitorenter(false),
470 _pending_transfer_to_interpreter(false),
471 _pending_failed_speculation(0),
472 _jvmci{nullptr},
473 _libjvmci_runtime(nullptr),
474 _jvmci_counters(nullptr),
475 _jvmci_reserved0(0),
476 _jvmci_reserved1(0),
477 _jvmci_reserved_oop0(nullptr),
478 _live_nmethod(nullptr),
479 #endif // INCLUDE_JVMCI
480
481 _exception_oop(oop()),
482 _exception_pc(nullptr),
483 _exception_handler_pc(nullptr),
484 _is_method_handle_return(0),
485
486 _jni_active_critical(0),
487 _pending_jni_exception_check_fn(nullptr),
488 _depth_first_number(0),
489
490 // JVMTI PopFrame support
491 _popframe_condition(popframe_inactive),
492 _frames_to_pop_failed_realloc(0),
493
494 _cont_entry(nullptr),
495 _cont_fastpath(nullptr),
496 _cont_fastpath_thread_state(1),
497 _held_monitor_count(0),
498 _jni_monitor_count(0),
499 _unlocked_inflated_monitor(nullptr),
500
501 _can_call_java(true),
502
503 _preempt_alternate_return(nullptr),
504 _preemption_cancelled(false),
505 _pending_interrupted_exception(false),
506
507 _handshake(this),
508
509 _popframe_preserved_args(nullptr),
510 _popframe_preserved_args_size(0),
511
512 _jvmti_thread_state(nullptr),
513 _interp_only_mode(0),
514 _should_post_on_exceptions_flag(JNI_FALSE),
515 _thread_stat(new ThreadStatistics()),
516
517 _parker(),
518
519 _class_to_be_initialized(nullptr),
520 _class_being_initialized(nullptr),
521
522 _SleepEvent(ParkEvent::Allocate(this)),
523
524 #if INCLUDE_JFR
525 _last_freeze_fail_result(freeze_ok),
526 #endif
527
528 _lock_stack(this),
529 _om_cache(this) {
530 set_jni_functions(jni_functions());
531
532 #if INCLUDE_JVMCI
533 assert(_jvmci._implicit_exception_pc == nullptr, "must be");
534 if (JVMCICounterSize > 0) {
535 resize_counters(0, (int) JVMCICounterSize);
536 }
537 #endif // INCLUDE_JVMCI
538
539 // Setup safepoint state info for this thread
540 ThreadSafepointState::create(this);
541
542 SafepointMechanism::initialize_header(this);
543
544 set_requires_cross_modify_fence(false);
545
546 pd_initialize();
547 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
548 }
549
550 JavaThread* JavaThread::create_attaching_thread() {
551 JavaThread* jt = new JavaThread();
552 jt->_jni_attach_state = _attaching_via_jni;
553 return jt;
554 }
555
556 // interrupt support
557
558 void JavaThread::interrupt() {
559 // All callers should have 'this' thread protected by a
560 // ThreadsListHandle so that it cannot terminate and deallocate
561 // itself.
562 debug_only(check_for_dangling_thread_pointer(this);)
563
564 // For Windows _interrupt_event
565 WINDOWS_ONLY(osthread()->set_interrupted(true);)
566
567 // For Thread.sleep
568 _SleepEvent->unpark();
569
570 // For JSR166 LockSupport.park
571 parker()->unpark();
572
573 // For ObjectMonitor and JvmtiRawMonitor
574 _ParkEvent->unpark();
575 }
576
577 bool JavaThread::is_interrupted(bool clear_interrupted) {
578 debug_only(check_for_dangling_thread_pointer(this);)
579
580 if (_threadObj.peek() == nullptr) {
581 // If there is no j.l.Thread then it is impossible to have
582 // been interrupted. We can find null during VM initialization
583 // or when a JNI thread is still in the process of attaching.
584 // In such cases this must be the current thread.
585 assert(this == Thread::current(), "invariant");
586 return false;
587 }
588
589 bool interrupted = java_lang_Thread::interrupted(threadObj());
590
591 // NOTE that since there is no "lock" around the interrupt and
592 // is_interrupted operations, there is the possibility that the
593 // interrupted flag will be "false" but that the
594 // low-level events will be in the signaled state. This is
595 // intentional. The effect of this is that Object.wait() and
596 // LockSupport.park() will appear to have a spurious wakeup, which
597 // is allowed and not harmful, and the possibility is so rare that
598 // it is not worth the added complexity to add yet another lock.
599 // For the sleep event an explicit reset is performed on entry
600 // to JavaThread::sleep, so there is no early return. It has also been
601 // recommended not to put the interrupted flag into the "event"
602 // structure because it hides the issue.
603 // Also, because there is no lock, we must only clear the interrupt
604 // state if we are going to report that we were interrupted; otherwise
605 // an interrupt that happens just after we read the field would be lost.
606 if (interrupted && clear_interrupted) {
607 assert(this == Thread::current(), "only the current thread can clear");
608 java_lang_Thread::set_interrupted(threadObj(), false);
609 WINDOWS_ONLY(osthread()->set_interrupted(false);)
610 }
611 return interrupted;
612 }
613
614 // This is only for use by JVMTI RawMonitorWait. It emulates the actions of
615 // the Java code in Object::wait which are not present in RawMonitorWait.
616 bool JavaThread::get_and_clear_interrupted() {
617 if (!is_interrupted(false)) {
618 return false;
619 }
620 oop thread_oop = vthread_or_thread();
621 bool is_virtual = java_lang_VirtualThread::is_instance(thread_oop);
622
623 if (!is_virtual) {
624 return is_interrupted(true);
625 }
626 // Virtual thread: clear interrupt status for both virtual and
627 // carrier threads under the interruptLock protection.
628 JavaThread* current = JavaThread::current();
629 HandleMark hm(current);
630 Handle thread_h(current, thread_oop);
631 ObjectLocker lock(Handle(current, java_lang_Thread::interrupt_lock(thread_h())), current);
632
633 // re-check the interrupt status under the interruptLock protection
634 bool interrupted = java_lang_Thread::interrupted(thread_h());
635
636 if (interrupted) {
637 assert(this == Thread::current(), "only the current thread can clear");
638 java_lang_Thread::set_interrupted(thread_h(), false); // clear for virtual
639 java_lang_Thread::set_interrupted(threadObj(), false); // clear for carrier
640 WINDOWS_ONLY(osthread()->set_interrupted(false);)
641 }
642 return interrupted;
643 }
644
645 void JavaThread::block_if_vm_exited() {
646 if (_terminated == _vm_exited) {
647 // _vm_exited is set at safepoint, and Threads_lock is never released
648 // so we will block here forever.
649 // Here we can be doing a jump from a safe state to an unsafe state without
650 // proper transition, but it happens after the final safepoint has begun so
651 // this jump won't cause any safepoint problems.
652 set_thread_state(_thread_in_vm);
653 Threads_lock->lock();
654 ShouldNotReachHere();
655 }
656 }
657
658 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz, MemTag mem_tag) : JavaThread(mem_tag) {
659 set_entry_point(entry_point);
660 // Create the native thread itself.
661 // %note runtime_23
662 os::ThreadType thr_type = os::java_thread;
663 thr_type = entry_point == &CompilerThread::thread_entry ? os::compiler_thread :
664 os::java_thread;
665 os::create_thread(this, thr_type, stack_sz);
666 // The _osthread may be null here because we ran out of memory (too many threads active).
667 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
668 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
669 // the exception consists of creating the exception object & initializing it, initialization
670 // will leave the VM via a JavaCall and then all locks must be unlocked).
671 //
672 // The thread is still suspended when we reach here. Thread must be explicit started
673 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
674 // by calling Threads:add. The reason why this is not done here, is because the thread
675 // object must be fully initialized (take a look at JVM_Start)
676 }
677
678 JavaThread::~JavaThread() {
679
680 // Enqueue OopHandles for release by the service thread.
681 add_oop_handles_for_release();
682
683 // Return the sleep event to the free list
684 ParkEvent::Release(_SleepEvent);
685 _SleepEvent = nullptr;
686
687 // Free any remaining previous UnrollBlock
688 vframeArray* old_array = vframe_array_last();
689
690 if (old_array != nullptr) {
691 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
692 old_array->set_unroll_block(nullptr);
693 delete old_info;
694 delete old_array;
695 }
696
697 JvmtiDeferredUpdates* updates = deferred_updates();
698 if (updates != nullptr) {
699 // This can only happen if thread is destroyed before deoptimization occurs.
700 assert(updates->count() > 0, "Updates holder not deleted");
701 // free deferred updates.
702 delete updates;
703 set_deferred_updates(nullptr);
704 }
705
706 // All Java related clean up happens in exit
707 ThreadSafepointState::destroy(this);
708 if (_thread_stat != nullptr) delete _thread_stat;
709
710 #if INCLUDE_JVMCI
711 if (JVMCICounterSize > 0) {
712 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
713 }
714 #endif // INCLUDE_JVMCI
715 }
716
717
718 // First JavaThread specific code executed by a new Java thread.
719 void JavaThread::pre_run() {
720 // empty - see comments in run()
721 }
722
723 // The main routine called by a new Java thread. This isn't overridden
724 // by subclasses, instead different subclasses define a different "entry_point"
725 // which defines the actual logic for that kind of thread.
726 void JavaThread::run() {
727 // initialize thread-local alloc buffer related fields
728 initialize_tlab();
729
730 _stack_overflow_state.create_stack_guard_pages();
731
732 cache_global_variables();
733
734 // Thread is now sufficiently initialized to be handled by the safepoint code as being
735 // in the VM. Change thread state from _thread_new to _thread_in_vm
736 assert(this->thread_state() == _thread_new, "wrong thread state");
737 set_thread_state(_thread_in_vm);
738
739 // Before a thread is on the threads list it is always safe, so after leaving the
740 // _thread_new we should emit a instruction barrier. The distance to modified code
741 // from here is probably far enough, but this is consistent and safe.
742 OrderAccess::cross_modify_fence();
743
744 assert(JavaThread::current() == this, "sanity check");
745 assert(!Thread::current()->owns_locks(), "sanity check");
746
747 DTRACE_THREAD_PROBE(start, this);
748
749 // This operation might block. We call that after all safepoint checks for a new thread has
750 // been completed.
751 set_active_handles(JNIHandleBlock::allocate_block());
752
753 if (JvmtiExport::should_post_thread_life()) {
754 JvmtiExport::post_thread_start(this);
755
756 }
757
758 if (AlwaysPreTouchStacks) {
759 pretouch_stack();
760 }
761
762 // We call another function to do the rest so we are sure that the stack addresses used
763 // from there will be lower than the stack base just computed.
764 thread_main_inner();
765 }
766
767 void JavaThread::thread_main_inner() {
768 assert(JavaThread::current() == this, "sanity check");
769 assert(_threadObj.peek() != nullptr, "just checking");
770
771 // Execute thread entry point unless this thread has a pending exception.
772 // Note: Due to JVMTI StopThread we can have pending exceptions already!
773 if (!this->has_pending_exception()) {
774 {
775 ResourceMark rm(this);
776 this->set_native_thread_name(this->name());
777 }
778 HandleMark hm(this);
779 this->entry_point()(this, this);
780 }
781
782 DTRACE_THREAD_PROBE(stop, this);
783
784 // Cleanup is handled in post_run()
785 }
786
787 // Shared teardown for all JavaThreads
788 void JavaThread::post_run() {
789 this->exit(false);
790 this->unregister_thread_stack_with_NMT();
791 // Defer deletion to here to ensure 'this' is still referenceable in call_run
792 // for any shared tear-down.
793 this->smr_delete();
794 }
795
796 static void ensure_join(JavaThread* thread) {
797 // We do not need to grab the Threads_lock, since we are operating on ourself.
798 Handle threadObj(thread, thread->threadObj());
799 assert(threadObj.not_null(), "java thread object must exist");
800 ObjectLocker lock(threadObj, thread);
801 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
802 java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED);
803 // Clear the native thread instance - this makes isAlive return false and allows the join()
804 // to complete once we've done the notify_all below. Needs a release() to obey Java Memory Model
805 // requirements.
806 assert(java_lang_Thread::thread(threadObj()) == thread, "must be alive");
807 java_lang_Thread::release_set_thread(threadObj(), nullptr);
808 lock.notify_all(thread);
809 // Ignore pending exception, since we are exiting anyway
810 thread->clear_pending_exception();
811 }
812
813 static bool is_daemon(oop threadObj) {
814 return (threadObj != nullptr && java_lang_Thread::is_daemon(threadObj));
815 }
816
817 // For any new cleanup additions, please check to see if they need to be applied to
818 // cleanup_failed_attach_current_thread as well.
819 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
820 assert(this == JavaThread::current(), "thread consistency check");
821 assert(!is_exiting(), "should not be exiting or terminated already");
822
823 elapsedTimer _timer_exit_phase1;
824 elapsedTimer _timer_exit_phase2;
825 elapsedTimer _timer_exit_phase3;
826 elapsedTimer _timer_exit_phase4;
827
828 om_clear_monitor_cache();
829
830 if (log_is_enabled(Debug, os, thread, timer)) {
831 _timer_exit_phase1.start();
832 }
833
834 HandleMark hm(this);
835 Handle uncaught_exception(this, this->pending_exception());
836 this->clear_pending_exception();
837 Handle threadObj(this, this->threadObj());
838 assert(threadObj.not_null(), "Java thread object should be created");
839
840 if (!destroy_vm) {
841 if (uncaught_exception.not_null()) {
842 EXCEPTION_MARK;
843 // Call method Thread.dispatchUncaughtException().
844 Klass* thread_klass = vmClasses::Thread_klass();
845 JavaValue result(T_VOID);
846 JavaCalls::call_virtual(&result,
847 threadObj, thread_klass,
848 vmSymbols::dispatchUncaughtException_name(),
849 vmSymbols::throwable_void_signature(),
850 uncaught_exception,
851 THREAD);
852 if (HAS_PENDING_EXCEPTION) {
853 ResourceMark rm(this);
854 jio_fprintf(defaultStream::error_stream(),
855 "\nException: %s thrown from the UncaughtExceptionHandler"
856 " in thread \"%s\"\n",
857 pending_exception()->klass()->external_name(),
858 name());
859 CLEAR_PENDING_EXCEPTION;
860 }
861 }
862
863 if (!is_Compiler_thread()) {
864 // We have finished executing user-defined Java code and now have to do the
865 // implementation specific clean-up by calling Thread.exit(). We prevent any
866 // asynchronous exceptions from being delivered while in Thread.exit()
867 // to ensure the clean-up is not corrupted.
868 NoAsyncExceptionDeliveryMark _no_async(this);
869
870 EXCEPTION_MARK;
871 JavaValue result(T_VOID);
872 Klass* thread_klass = vmClasses::Thread_klass();
873 JavaCalls::call_virtual(&result,
874 threadObj, thread_klass,
875 vmSymbols::exit_method_name(),
876 vmSymbols::void_method_signature(),
877 THREAD);
878 CLEAR_PENDING_EXCEPTION;
879 }
880
881 // notify JVMTI
882 if (JvmtiExport::should_post_thread_life()) {
883 JvmtiExport::post_thread_end(this);
884 }
885 } else {
886 // before_exit() has already posted JVMTI THREAD_END events
887 }
888
889 // Cleanup any pending async exception now since we cannot access oops after
890 // BarrierSet::barrier_set()->on_thread_detach() has been executed.
891 if (has_async_exception_condition()) {
892 handshake_state()->clean_async_exception_operation();
893 }
894
895 // The careful dance between thread suspension and exit is handled here.
896 // Since we are in thread_in_vm state and suspension is done with handshakes,
897 // we can just put in the exiting state and it will be correctly handled.
898 // Also, no more async exceptions will be added to the queue after this point.
899 set_terminated(_thread_exiting);
900 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
901
902 if (log_is_enabled(Debug, os, thread, timer)) {
903 _timer_exit_phase1.stop();
904 _timer_exit_phase2.start();
905 }
906
907 // Capture daemon status before the thread is marked as terminated.
908 bool daemon = is_daemon(threadObj());
909
910 // Notify waiters on thread object. This has to be done after exit() is called
911 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
912 // group should have the destroyed bit set before waiters are notified).
913 ensure_join(this);
914 assert(!this->has_pending_exception(), "ensure_join should have cleared");
915
916 if (log_is_enabled(Debug, os, thread, timer)) {
917 _timer_exit_phase2.stop();
918 _timer_exit_phase3.start();
919 }
920 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
921 // held by this thread must be released. The spec does not distinguish
922 // between JNI-acquired and regular Java monitors. We can only see
923 // regular Java monitors here if monitor enter-exit matching is broken.
924 //
925 // ensure_join() ignores IllegalThreadStateExceptions, and so does
926 // ObjectSynchronizer::release_monitors_owned_by_thread().
927 if (exit_type == jni_detach) {
928 // Sanity check even though JNI DetachCurrentThread() would have
929 // returned JNI_ERR if there was a Java frame. JavaThread exit
930 // should be done executing Java code by the time we get here.
931 assert(!this->has_last_Java_frame(),
932 "should not have a Java frame when detaching or exiting");
933 ObjectSynchronizer::release_monitors_owned_by_thread(this);
934 assert(!this->has_pending_exception(), "release_monitors should have cleared");
935 // Check for monitor counts being out of sync.
936 assert(held_monitor_count() == jni_monitor_count(),
937 "held monitor count should be equal to jni: %zd != %zd",
938 held_monitor_count(), jni_monitor_count());
939 // All in-use monitors, including JNI-locked ones, should have been released above.
940 assert(held_monitor_count() == 0, "Failed to unlock %zd object monitors",
941 held_monitor_count());
942 } else {
943 // Check for monitor counts being out of sync.
944 assert(held_monitor_count() == jni_monitor_count(),
945 "held monitor count should be equal to jni: %zd != %zd",
946 held_monitor_count(), jni_monitor_count());
947 // It is possible that a terminating thread failed to unlock monitors it locked
948 // via JNI so we don't assert the count is zero.
949 }
950
951 if (CheckJNICalls && jni_monitor_count() > 0) {
952 // We would like a fatal here, but due to we never checked this before there
953 // is a lot of tests which breaks, even with an error log.
954 log_debug(jni)("JavaThread %s (tid: %zu) with Objects still locked by JNI MonitorEnter.",
955 exit_type == JavaThread::normal_exit ? "exiting" : "detaching", os::current_thread_id());
956 }
957
958 // These things needs to be done while we are still a Java Thread. Make sure that thread
959 // is in a consistent state, in case GC happens
960 JFR_ONLY(Jfr::on_thread_exit(this);)
961
962 if (active_handles() != nullptr) {
963 JNIHandleBlock* block = active_handles();
964 set_active_handles(nullptr);
965 JNIHandleBlock::release_block(block);
966 }
967
968 if (free_handle_block() != nullptr) {
969 JNIHandleBlock* block = free_handle_block();
970 set_free_handle_block(nullptr);
971 JNIHandleBlock::release_block(block);
972 }
973
974 // These have to be removed while this is still a valid thread.
975 _stack_overflow_state.remove_stack_guard_pages();
976
977 if (UseTLAB) {
978 tlab().retire();
979 }
980
981 if (JvmtiEnv::environments_might_exist()) {
982 JvmtiExport::cleanup_thread(this);
983 }
984
985 // We need to cache the thread name for logging purposes below as once
986 // we have called on_thread_detach this thread must not access any oops.
987 char* thread_name = nullptr;
988 if (log_is_enabled(Debug, os, thread, timer) || (CountBytecodesPerThread && log_is_enabled(Info, init))) {
989 ResourceMark rm(this);
990 thread_name = os::strdup(name());
991 }
992
993 if (log_is_enabled(Info, os, thread)) {
994 ResourceMark rm(this);
995 log_info(os, thread)("JavaThread %s (name: \"%s\", tid: %zu).",
996 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
997 name(), os::current_thread_id());
998 }
999
1000 if (log_is_enabled(Debug, os, thread, timer)) {
1001 _timer_exit_phase3.stop();
1002 _timer_exit_phase4.start();
1003 }
1004
1005 #if INCLUDE_JVMCI
1006 if (JVMCICounterSize > 0) {
1007 if (jvmci_counters_include(this)) {
1008 for (int i = 0; i < JVMCICounterSize; i++) {
1009 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1010 }
1011 }
1012 }
1013 #endif // INCLUDE_JVMCI
1014
1015 if (bc_counter_value() > 0) {
1016 log_info(init)("Thread '%s': " JLONG_FORMAT " bytecodes executed (during clinit: " JLONG_FORMAT ")",
1017 thread_name, bc_counter_value(), clinit_bc_counter_value());
1018 }
1019
1020 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread.
1021 // We call BarrierSet::barrier_set()->on_thread_detach() here so no touching of oops after this point.
1022 Threads::remove(this, daemon);
1023
1024 if (log_is_enabled(Debug, os, thread, timer)) {
1025 _timer_exit_phase4.stop();
1026 log_debug(os, thread, timer)("name='%s'"
1027 ", exit-phase1=" JLONG_FORMAT
1028 ", exit-phase2=" JLONG_FORMAT
1029 ", exit-phase3=" JLONG_FORMAT
1030 ", exit-phase4=" JLONG_FORMAT,
1031 thread_name,
1032 _timer_exit_phase1.milliseconds(),
1033 _timer_exit_phase2.milliseconds(),
1034 _timer_exit_phase3.milliseconds(),
1035 _timer_exit_phase4.milliseconds());
1036 os::free(thread_name);
1037 }
1038 }
1039
1040 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
1041 if (active_handles() != nullptr) {
1042 JNIHandleBlock* block = active_handles();
1043 set_active_handles(nullptr);
1044 JNIHandleBlock::release_block(block);
1045 }
1046
1047 if (free_handle_block() != nullptr) {
1048 JNIHandleBlock* block = free_handle_block();
1049 set_free_handle_block(nullptr);
1050 JNIHandleBlock::release_block(block);
1051 }
1052
1053 // These have to be removed while this is still a valid thread.
1054 _stack_overflow_state.remove_stack_guard_pages();
1055
1056 if (UseTLAB) {
1057 tlab().retire();
1058 }
1059
1060 Threads::remove(this, is_daemon);
1061 }
1062
1063 JavaThread* JavaThread::active() {
1064 Thread* thread = Thread::current();
1065 if (thread->is_Java_thread()) {
1066 return JavaThread::cast(thread);
1067 } else {
1068 assert(thread->is_VM_thread(), "this must be a vm thread");
1069 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1070 JavaThread *ret = op == nullptr ? nullptr : JavaThread::cast(op->calling_thread());
1071 return ret;
1072 }
1073 }
1074
1075 bool JavaThread::is_lock_owned(address adr) const {
1076 assert(LockingMode != LM_LIGHTWEIGHT, "should not be called with new lightweight locking");
1077 return is_in_full_stack(adr);
1078 }
1079
1080 oop JavaThread::exception_oop() const {
1081 return Atomic::load(&_exception_oop);
1082 }
1083
1084 void JavaThread::set_exception_oop(oop o) {
1085 Atomic::store(&_exception_oop, o);
1086 }
1087
1088 void JavaThread::handle_special_runtime_exit_condition() {
1089 if (is_obj_deopt_suspend()) {
1090 frame_anchor()->make_walkable();
1091 wait_for_object_deoptimization();
1092 }
1093 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
1094 }
1095
1096
1097 // Asynchronous exceptions support
1098 //
1099 void JavaThread::handle_async_exception(oop java_throwable) {
1100 assert(java_throwable != nullptr, "should have an _async_exception to throw");
1101 assert(!is_at_poll_safepoint(), "should have never called this method");
1102
1103 if (has_last_Java_frame()) {
1104 frame f = last_frame();
1105 if (f.is_runtime_frame()) {
1106 // If the topmost frame is a runtime stub, then we are calling into
1107 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1108 // must deoptimize the caller before continuing, as the compiled exception
1109 // handler table may not be valid.
1110 RegisterMap reg_map(this,
1111 RegisterMap::UpdateMap::skip,
1112 RegisterMap::ProcessFrames::include,
1113 RegisterMap::WalkContinuation::skip);
1114 frame compiled_frame = f.sender(®_map);
1115 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1116 Deoptimization::deoptimize(this, compiled_frame);
1117 }
1118 }
1119 }
1120
1121 // We cannot call Exceptions::_throw(...) here because we cannot block
1122 set_pending_exception(java_throwable, __FILE__, __LINE__);
1123
1124 clear_scopedValueBindings();
1125
1126 LogTarget(Info, exceptions) lt;
1127 if (lt.is_enabled()) {
1128 ResourceMark rm;
1129 LogStream ls(lt);
1130 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1131 if (has_last_Java_frame()) {
1132 frame f = last_frame();
1133 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1134 }
1135 ls.print_cr(" of type: %s", java_throwable->klass()->external_name());
1136 }
1137 }
1138
1139 void JavaThread::install_async_exception(AsyncExceptionHandshake* aeh) {
1140 // Do not throw asynchronous exceptions against the compiler thread
1141 // or if the thread is already exiting.
1142 if (!can_call_java() || is_exiting()) {
1143 delete aeh;
1144 return;
1145 }
1146
1147 oop exception = aeh->exception();
1148 Handshake::execute(aeh, this); // Install asynchronous handshake
1149
1150 ResourceMark rm;
1151 if (log_is_enabled(Info, exceptions)) {
1152 log_info(exceptions)("Pending Async. exception installed of type: %s",
1153 InstanceKlass::cast(exception->klass())->external_name());
1154 }
1155 // for AbortVMOnException flag
1156 Exceptions::debug_check_abort(exception->klass()->external_name());
1157
1158 oop vt_oop = vthread();
1159 if (vt_oop == nullptr || !vt_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1160 // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1161 java_lang_Thread::set_interrupted(threadObj(), true);
1162 this->interrupt();
1163 }
1164 }
1165
1166 class InstallAsyncExceptionHandshake : public HandshakeClosure {
1167 AsyncExceptionHandshake* _aeh;
1168 public:
1169 InstallAsyncExceptionHandshake(AsyncExceptionHandshake* aeh) :
1170 HandshakeClosure("InstallAsyncException"), _aeh(aeh) {}
1171 ~InstallAsyncExceptionHandshake() {
1172 // If InstallAsyncExceptionHandshake was never executed we need to clean up _aeh.
1173 delete _aeh;
1174 }
1175 void do_thread(Thread* thr) {
1176 JavaThread* target = JavaThread::cast(thr);
1177 target->install_async_exception(_aeh);
1178 _aeh = nullptr;
1179 }
1180 };
1181
1182 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
1183 OopHandle e(Universe::vm_global(), java_throwable);
1184 InstallAsyncExceptionHandshake iaeh(new AsyncExceptionHandshake(e));
1185 Handshake::execute(&iaeh, target);
1186 }
1187
1188 #if INCLUDE_JVMTI
1189 void JavaThread::set_is_in_VTMS_transition(bool val) {
1190 assert(is_in_VTMS_transition() != val, "already %s transition", val ? "inside" : "outside");
1191 _is_in_VTMS_transition = val;
1192 }
1193
1194 #ifdef ASSERT
1195 void JavaThread::set_is_VTMS_transition_disabler(bool val) {
1196 _is_VTMS_transition_disabler = val;
1197 }
1198 #endif
1199 #endif
1200
1201 // External suspension mechanism.
1202 //
1203 // Guarantees on return (for a valid target thread):
1204 // - Target thread will not execute any new bytecode.
1205 // - Target thread will not enter any new monitors.
1206 //
1207 bool JavaThread::java_suspend() {
1208 #if INCLUDE_JVMTI
1209 // Suspending a JavaThread in VTMS transition or disabling VTMS transitions can cause deadlocks.
1210 assert(!is_in_VTMS_transition(), "no suspend allowed in VTMS transition");
1211 assert(!is_VTMS_transition_disabler(), "no suspend allowed for VTMS transition disablers");
1212 #endif
1213
1214 guarantee(Thread::is_JavaThread_protected(/* target */ this),
1215 "target JavaThread is not protected in calling context.");
1216 return this->handshake_state()->suspend();
1217 }
1218
1219 bool JavaThread::java_resume() {
1220 guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1221 "missing ThreadsListHandle in calling context.");
1222 return this->handshake_state()->resume();
1223 }
1224
1225 // Wait for another thread to perform object reallocation and relocking on behalf of
1226 // this thread. The current thread is required to change to _thread_blocked in order
1227 // to be seen to be safepoint/handshake safe whilst suspended and only after becoming
1228 // handshake safe, the other thread can complete the handshake used to synchronize
1229 // with this thread and then perform the reallocation and relocking.
1230 // See EscapeBarrier::sync_and_suspend_*()
1231
1232 void JavaThread::wait_for_object_deoptimization() {
1233 assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1234 assert(this == Thread::current(), "invariant");
1235
1236 bool spin_wait = os::is_MP();
1237 do {
1238 ThreadBlockInVM tbivm(this, true /* allow_suspend */);
1239 // Wait for object deoptimization if requested.
1240 if (spin_wait) {
1241 // A single deoptimization is typically very short. Microbenchmarks
1242 // showed 5% better performance when spinning.
1243 const uint spin_limit = 10 * SpinYield::default_spin_limit;
1244 SpinYield spin(spin_limit);
1245 for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1246 spin.wait();
1247 }
1248 // Spin just once
1249 spin_wait = false;
1250 } else {
1251 MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1252 if (is_obj_deopt_suspend()) {
1253 ml.wait();
1254 }
1255 }
1256 // A handshake for obj. deoptimization suspend could have been processed so
1257 // we must check after processing.
1258 } while (is_obj_deopt_suspend());
1259 }
1260
1261 #ifdef ASSERT
1262 // Verify the JavaThread has not yet been published in the Threads::list, and
1263 // hence doesn't need protection from concurrent access at this stage.
1264 void JavaThread::verify_not_published() {
1265 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1266 // since an unpublished JavaThread doesn't participate in the
1267 // Thread-SMR protocol for keeping a ThreadsList alive.
1268 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1269 }
1270 #endif
1271
1272 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1273 // pending, when _suspend_flags is non-zero or when we need to process a stack
1274 // watermark. Also check for pending async exceptions (except unsafe access error).
1275 // Note only the native==>Java barriers can call this function when thread state
1276 // is _thread_in_native_trans.
1277 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1278 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1279 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1280
1281 thread->set_thread_state(_thread_in_vm);
1282
1283 // Enable WXWrite: called directly from interpreter native wrapper.
1284 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1285
1286 SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
1287
1288 // After returning from native, it could be that the stack frames are not
1289 // yet safe to use. We catch such situations in the subsequent stack watermark
1290 // barrier, which will trap unsafe stack frames.
1291 StackWatermarkSet::before_unwind(thread);
1292 }
1293
1294 #ifndef PRODUCT
1295 // Deoptimization
1296 // Function for testing deoptimization
1297 void JavaThread::deoptimize() {
1298 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1299 bool deopt = false; // Dump stack only if a deopt actually happens.
1300 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1301 // Iterate over all frames in the thread and deoptimize
1302 for (; !fst.is_done(); fst.next()) {
1303 if (fst.current()->can_be_deoptimized()) {
1304
1305 if (only_at) {
1306 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
1307 // consists of comma or carriage return separated numbers so
1308 // search for the current bci in that string.
1309 address pc = fst.current()->pc();
1310 nmethod* nm = fst.current()->cb()->as_nmethod();
1311 ScopeDesc* sd = nm->scope_desc_at(pc);
1312 char buffer[8];
1313 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1314 size_t len = strlen(buffer);
1315 const char * found = strstr(DeoptimizeOnlyAt, buffer);
1316 while (found != nullptr) {
1317 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1318 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1319 // Check that the bci found is bracketed by terminators.
1320 break;
1321 }
1322 found = strstr(found + 1, buffer);
1323 }
1324 if (!found) {
1325 continue;
1326 }
1327 }
1328
1329 if (DebugDeoptimization && !deopt) {
1330 deopt = true; // One-time only print before deopt
1331 tty->print_cr("[BEFORE Deoptimization]");
1332 trace_frames();
1333 trace_stack();
1334 }
1335 Deoptimization::deoptimize(this, *fst.current());
1336 }
1337 }
1338
1339 if (DebugDeoptimization && deopt) {
1340 tty->print_cr("[AFTER Deoptimization]");
1341 trace_frames();
1342 }
1343 }
1344
1345
1346 // Make zombies
1347 void JavaThread::make_zombies() {
1348 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1349 if (fst.current()->can_be_deoptimized()) {
1350 // it is a Java nmethod
1351 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1352 assert(nm != nullptr, "did not find nmethod");
1353 nm->make_not_entrant();
1354 }
1355 }
1356 }
1357 #endif // PRODUCT
1358
1359
1360 void JavaThread::deoptimize_marked_methods() {
1361 if (!has_last_Java_frame()) return;
1362 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1363 for (; !fst.is_done(); fst.next()) {
1364 if (fst.current()->should_be_deoptimized()) {
1365 Deoptimization::deoptimize(this, *fst.current());
1366 }
1367 }
1368 }
1369
1370 #ifdef ASSERT
1371 void JavaThread::verify_frame_info() {
1372 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1373 (has_last_Java_frame() && java_call_counter() > 0),
1374 "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1375 has_last_Java_frame() ? "true" : "false", java_call_counter());
1376 }
1377 #endif
1378
1379 // Push on a new block of JNI handles.
1380 void JavaThread::push_jni_handle_block() {
1381 // Allocate a new block for JNI handles.
1382 // Inlined code from jni_PushLocalFrame()
1383 JNIHandleBlock* old_handles = active_handles();
1384 JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this);
1385 assert(old_handles != nullptr && new_handles != nullptr, "should not be null");
1386 new_handles->set_pop_frame_link(old_handles); // make sure java handles get gc'd.
1387 set_active_handles(new_handles);
1388 }
1389
1390 // Pop off the current block of JNI handles.
1391 void JavaThread::pop_jni_handle_block() {
1392 // Release our JNI handle block
1393 JNIHandleBlock* old_handles = active_handles();
1394 JNIHandleBlock* new_handles = old_handles->pop_frame_link();
1395 assert(new_handles != nullptr, "should never set active handles to null");
1396 set_active_handles(new_handles);
1397 old_handles->set_pop_frame_link(nullptr);
1398 JNIHandleBlock::release_block(old_handles, this);
1399 }
1400
1401 void JavaThread::oops_do_no_frames(OopClosure* f, NMethodClosure* cf) {
1402 // Verify that the deferred card marks have been flushed.
1403 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1404
1405 // Traverse the GCHandles
1406 Thread::oops_do_no_frames(f, cf);
1407
1408 if (active_handles() != nullptr) {
1409 active_handles()->oops_do(f);
1410 }
1411
1412 DEBUG_ONLY(verify_frame_info();)
1413
1414 assert(vframe_array_head() == nullptr, "deopt in progress at a safepoint!");
1415 // If we have deferred set_locals there might be oops waiting to be
1416 // written
1417 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1418 if (list != nullptr) {
1419 for (int i = 0; i < list->length(); i++) {
1420 list->at(i)->oops_do(f);
1421 }
1422 }
1423
1424 // Traverse instance variables at the end since the GC may be moving things
1425 // around using this function
1426 f->do_oop((oop*) &_vm_result);
1427 f->do_oop((oop*) &_exception_oop);
1428 #if INCLUDE_JVMCI
1429 f->do_oop((oop*) &_jvmci_reserved_oop0);
1430
1431 if (_live_nmethod != nullptr && cf != nullptr) {
1432 cf->do_nmethod(_live_nmethod);
1433 }
1434 #endif
1435
1436 if (jvmti_thread_state() != nullptr) {
1437 jvmti_thread_state()->oops_do(f, cf);
1438 }
1439
1440 // The continuation oops are really on the stack. But there is typically at most
1441 // one of those per thread, so we handle them here in the oops_do_no_frames part
1442 // so that we don't have to sprinkle as many stack watermark checks where these
1443 // oops are used. We just need to make sure the thread has started processing.
1444 ContinuationEntry* entry = _cont_entry;
1445 while (entry != nullptr) {
1446 f->do_oop((oop*)entry->cont_addr());
1447 f->do_oop((oop*)entry->chunk_addr());
1448 entry = entry->parent();
1449 }
1450
1451 if (LockingMode == LM_LIGHTWEIGHT) {
1452 lock_stack().oops_do(f);
1453 }
1454 }
1455
1456 void JavaThread::oops_do_frames(OopClosure* f, NMethodClosure* cf) {
1457 if (!has_last_Java_frame()) {
1458 return;
1459 }
1460 // Finish any pending lazy GC activity for the frames
1461 StackWatermarkSet::finish_processing(this, nullptr /* context */, StackWatermarkKind::gc);
1462 // Traverse the execution stack
1463 for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1464 fst.current()->oops_do(f, cf, fst.register_map());
1465 }
1466 }
1467
1468 #ifdef ASSERT
1469 void JavaThread::verify_states_for_handshake() {
1470 // This checks that the thread has a correct frame state during a handshake.
1471 verify_frame_info();
1472 }
1473 #endif
1474
1475 void JavaThread::nmethods_do(NMethodClosure* cf) {
1476 DEBUG_ONLY(verify_frame_info();)
1477 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current());)
1478
1479 if (has_last_Java_frame()) {
1480 // Traverse the execution stack
1481 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1482 fst.current()->nmethod_do(cf);
1483 }
1484 }
1485
1486 if (jvmti_thread_state() != nullptr) {
1487 jvmti_thread_state()->nmethods_do(cf);
1488 }
1489
1490 #if INCLUDE_JVMCI
1491 if (_live_nmethod != nullptr) {
1492 cf->do_nmethod(_live_nmethod);
1493 }
1494 #endif
1495 }
1496
1497 void JavaThread::metadata_do(MetadataClosure* f) {
1498 if (has_last_Java_frame()) {
1499 // Traverse the execution stack to call f() on the methods in the stack
1500 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1501 fst.current()->metadata_do(f);
1502 }
1503 } else if (is_Compiler_thread()) {
1504 // need to walk ciMetadata in current compile tasks to keep alive.
1505 CompilerThread* ct = (CompilerThread*)this;
1506 if (ct->env() != nullptr) {
1507 ct->env()->metadata_do(f);
1508 }
1509 CompileTask* task = ct->task();
1510 if (task != nullptr) {
1511 task->metadata_do(f);
1512 }
1513 }
1514 }
1515
1516 // Printing
1517 static const char* _get_thread_state_name(JavaThreadState _thread_state) {
1518 switch (_thread_state) {
1519 case _thread_uninitialized: return "_thread_uninitialized";
1520 case _thread_new: return "_thread_new";
1521 case _thread_new_trans: return "_thread_new_trans";
1522 case _thread_in_native: return "_thread_in_native";
1523 case _thread_in_native_trans: return "_thread_in_native_trans";
1524 case _thread_in_vm: return "_thread_in_vm";
1525 case _thread_in_vm_trans: return "_thread_in_vm_trans";
1526 case _thread_in_Java: return "_thread_in_Java";
1527 case _thread_in_Java_trans: return "_thread_in_Java_trans";
1528 case _thread_blocked: return "_thread_blocked";
1529 case _thread_blocked_trans: return "_thread_blocked_trans";
1530 default: return "unknown thread state";
1531 }
1532 }
1533
1534 void JavaThread::print_thread_state_on(outputStream *st) const {
1535 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
1536 }
1537
1538 // Called by Threads::print() for VM_PrintThreads operation
1539 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
1540 st->print_raw("\"");
1541 st->print_raw(name());
1542 st->print_raw("\" ");
1543 oop thread_oop = threadObj();
1544 if (thread_oop != nullptr) {
1545 st->print("#" INT64_FORMAT " [%ld] ", (int64_t)java_lang_Thread::thread_id(thread_oop), (long) osthread()->thread_id());
1546 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
1547 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
1548 }
1549 Thread::print_on(st, print_extended_info);
1550 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
1551 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
1552 if (thread_oop != nullptr) {
1553 if (is_vthread_mounted()) {
1554 st->print_cr(" Carrying virtual thread #" INT64_FORMAT, java_lang_Thread::thread_id(vthread()));
1555 } else {
1556 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
1557 }
1558 }
1559 #ifndef PRODUCT
1560 _safepoint_state->print_on(st);
1561 #endif // PRODUCT
1562 if (is_Compiler_thread()) {
1563 CompileTask *task = ((CompilerThread*)this)->task();
1564 if (task != nullptr) {
1565 st->print(" Compiling: ");
1566 task->print(st, nullptr, true, false);
1567 } else {
1568 st->print(" No compile task");
1569 }
1570 st->cr();
1571 }
1572 }
1573
1574 void JavaThread::print() const { print_on(tty); }
1575
1576 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
1577 st->print("%s", get_thread_name_string(buf, buflen));
1578 }
1579
1580 // Called by fatal error handler. The difference between this and
1581 // JavaThread::print() is that we can't grab lock or allocate memory.
1582 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
1583 st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
1584 Thread* current = Thread::current_or_null_safe();
1585 assert(current != nullptr, "cannot be called by a detached thread");
1586 st->fill_to(60);
1587 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1588 // Only access threadObj() if current thread is not a JavaThread
1589 // or if it is a JavaThread that can safely access oops.
1590 oop thread_obj = threadObj();
1591 if (thread_obj != nullptr) {
1592 st->print(java_lang_Thread::is_daemon(thread_obj) ? " daemon" : " ");
1593 }
1594 }
1595 st->print(" [");
1596 st->print("%s", _get_thread_state_name(_thread_state));
1597 if (osthread()) {
1598 st->print(", id=%d", osthread()->thread_id());
1599 }
1600 // Use raw field members for stack base/size as this could be
1601 // called before a thread has run enough to initialize them.
1602 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ") (" PROPERFMT ")",
1603 p2i(_stack_base - _stack_size), p2i(_stack_base),
1604 PROPERFMTARGS(_stack_size));
1605 st->print("]");
1606
1607 ThreadsSMRSupport::print_info_on(this, st);
1608 return;
1609 }
1610
1611
1612 // Verification
1613
1614 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
1615 // ignore if there is no stack
1616 if (!has_last_Java_frame()) return;
1617 // traverse the stack frames. Starts from top frame.
1618 for (StackFrameStream fst(this, true /* update_map */, true /* process_frames */, false /* walk_cont */); !fst.is_done(); fst.next()) {
1619 frame* fr = fst.current();
1620 f(fr, fst.register_map());
1621 }
1622 }
1623
1624 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
1625
1626 void JavaThread::verify() {
1627 // Verify oops in the thread.
1628 oops_do(&VerifyOopClosure::verify_oop, nullptr);
1629
1630 // Verify the stack frames.
1631 frames_do(frame_verify);
1632 }
1633
1634 // CR 6300358 (sub-CR 2137150)
1635 // Most callers of this method assume that it can't return null but a
1636 // thread may not have a name whilst it is in the process of attaching to
1637 // the VM - see CR 6412693, and there are places where a JavaThread can be
1638 // seen prior to having its threadObj set (e.g., JNI attaching threads and
1639 // if vm exit occurs during initialization). These cases can all be accounted
1640 // for such that this method never returns null.
1641 const char* JavaThread::name() const {
1642 if (Thread::is_JavaThread_protected(/* target */ this)) {
1643 // The target JavaThread is protected so get_thread_name_string() is safe:
1644 return get_thread_name_string();
1645 }
1646
1647 // The target JavaThread is not protected so we return the default:
1648 return Thread::name();
1649 }
1650
1651 // Like name() but doesn't include the protection check. This must only be
1652 // called when it is known to be safe, even though the protection check can't tell
1653 // that e.g. when this thread is the init_thread() - see instanceKlass.cpp.
1654 const char* JavaThread::name_raw() const {
1655 return get_thread_name_string();
1656 }
1657
1658 // Returns a non-null representation of this thread's name, or a suitable
1659 // descriptive string if there is no set name.
1660 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
1661 const char* name_str;
1662 #ifdef ASSERT
1663 Thread* current = Thread::current_or_null_safe();
1664 assert(current != nullptr, "cannot be called by a detached thread");
1665 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1666 // Only access threadObj() if current thread is not a JavaThread
1667 // or if it is a JavaThread that can safely access oops.
1668 #endif
1669 oop thread_obj = threadObj();
1670 if (thread_obj != nullptr) {
1671 oop name = java_lang_Thread::name(thread_obj);
1672 if (name != nullptr) {
1673 if (buf == nullptr) {
1674 name_str = java_lang_String::as_utf8_string(name);
1675 } else {
1676 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
1677 }
1678 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
1679 name_str = "<no-name - thread is attaching>";
1680 } else {
1681 name_str = "<un-named>";
1682 }
1683 } else {
1684 name_str = Thread::name();
1685 }
1686 #ifdef ASSERT
1687 } else {
1688 // Current JavaThread has exited...
1689 if (current == this) {
1690 // ... and is asking about itself:
1691 name_str = "<no-name - current JavaThread has exited>";
1692 } else {
1693 // ... and it can't safely determine this JavaThread's name so
1694 // use the default thread name.
1695 name_str = Thread::name();
1696 }
1697 }
1698 #endif
1699 assert(name_str != nullptr, "unexpected null thread name");
1700 return name_str;
1701 }
1702
1703 // Helper to extract the name from the thread oop for logging.
1704 const char* JavaThread::name_for(oop thread_obj) {
1705 assert(thread_obj != nullptr, "precondition");
1706 oop name = java_lang_Thread::name(thread_obj);
1707 const char* name_str;
1708 if (name != nullptr) {
1709 name_str = java_lang_String::as_utf8_string(name);
1710 } else {
1711 name_str = "<un-named>";
1712 }
1713 return name_str;
1714 }
1715
1716 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
1717
1718 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
1719 assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
1720 // Link Java Thread object <-> C++ Thread
1721
1722 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
1723 // and put it into a new Handle. The Handle "thread_oop" can then
1724 // be used to pass the C++ thread object to other methods.
1725
1726 // Set the Java level thread object (jthread) field of the
1727 // new thread (a JavaThread *) to C++ thread object using the
1728 // "thread_oop" handle.
1729
1730 // Set the thread field (a JavaThread *) of the
1731 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
1732
1733 Handle thread_oop(Thread::current(),
1734 JNIHandles::resolve_non_null(jni_thread));
1735 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
1736 "must be initialized");
1737 set_threadOopHandles(thread_oop());
1738 set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
1739
1740 if (prio == NoPriority) {
1741 prio = java_lang_Thread::priority(thread_oop());
1742 assert(prio != NoPriority, "A valid priority should be present");
1743 }
1744
1745 // Push the Java priority down to the native thread; needs Threads_lock
1746 Thread::set_priority(this, prio);
1747
1748 // Add the new thread to the Threads list and set it in motion.
1749 // We must have threads lock in order to call Threads::add.
1750 // It is crucial that we do not block before the thread is
1751 // added to the Threads list for if a GC happens, then the java_thread oop
1752 // will not be visited by GC.
1753 Threads::add(this);
1754 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
1755 // on a ThreadsList. We don't want to wait for the release when the
1756 // Theads_lock is dropped somewhere in the caller since the JavaThread*
1757 // is already visible to JVM/TI via the ThreadsList.
1758 java_lang_Thread::release_set_thread(thread_oop(), this);
1759 }
1760
1761 oop JavaThread::current_park_blocker() {
1762 // Support for JSR-166 locks
1763 oop thread_oop = threadObj();
1764 if (thread_oop != nullptr) {
1765 return java_lang_Thread::park_blocker(thread_oop);
1766 }
1767 return nullptr;
1768 }
1769
1770 // Print current stack trace for checked JNI warnings and JNI fatal errors.
1771 // This is the external format, selecting the platform or vthread
1772 // as applicable, and allowing for a native-only stack.
1773 void JavaThread::print_jni_stack() {
1774 assert(this == JavaThread::current(), "Can't print stack of other threads");
1775 if (!has_last_Java_frame()) {
1776 ResourceMark rm(this);
1777 char* buf = NEW_RESOURCE_ARRAY_RETURN_NULL(char, O_BUFLEN);
1778 if (buf == nullptr) {
1779 tty->print_cr("Unable to print native stack - out of memory");
1780 return;
1781 }
1782 NativeStackPrinter nsp(this);
1783 address lastpc = nullptr;
1784 nsp.print_stack(tty, buf, O_BUFLEN, lastpc,
1785 true /*print_source_info */, -1 /* max stack */ );
1786 } else {
1787 print_active_stack_on(tty);
1788 }
1789 }
1790
1791 void JavaThread::print_stack_on(outputStream* st) {
1792 if (!has_last_Java_frame()) return;
1793
1794 Thread* current_thread = Thread::current();
1795 ResourceMark rm(current_thread);
1796 HandleMark hm(current_thread);
1797
1798 RegisterMap reg_map(this,
1799 RegisterMap::UpdateMap::include,
1800 RegisterMap::ProcessFrames::include,
1801 RegisterMap::WalkContinuation::skip);
1802 vframe* start_vf = platform_thread_last_java_vframe(®_map);
1803 int count = 0;
1804 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1805 if (f->is_java_frame()) {
1806 javaVFrame* jvf = javaVFrame::cast(f);
1807 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1808
1809 // Print out lock information
1810 if (JavaMonitorsInStackTrace) {
1811 jvf->print_lock_info_on(st, count);
1812 }
1813 } else {
1814 // Ignore non-Java frames
1815 }
1816
1817 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1818 count++;
1819 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1820 }
1821 }
1822
1823 void JavaThread::print_vthread_stack_on(outputStream* st) {
1824 assert(is_vthread_mounted(), "Caller should have checked this");
1825 assert(has_last_Java_frame(), "must be");
1826
1827 Thread* current_thread = Thread::current();
1828 ResourceMark rm(current_thread);
1829 HandleMark hm(current_thread);
1830
1831 RegisterMap reg_map(this,
1832 RegisterMap::UpdateMap::include,
1833 RegisterMap::ProcessFrames::include,
1834 RegisterMap::WalkContinuation::include);
1835 ContinuationEntry* cont_entry = last_continuation();
1836 vframe* start_vf = last_java_vframe(®_map);
1837 int count = 0;
1838 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1839 // Watch for end of vthread stack
1840 if (Continuation::is_continuation_enterSpecial(f->fr())) {
1841 assert(cont_entry == Continuation::get_continuation_entry_for_entry_frame(this, f->fr()), "");
1842 if (cont_entry->is_virtual_thread()) {
1843 break;
1844 }
1845 cont_entry = cont_entry->parent();
1846 }
1847 if (f->is_java_frame()) {
1848 javaVFrame* jvf = javaVFrame::cast(f);
1849 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1850
1851 // Print out lock information
1852 if (JavaMonitorsInStackTrace) {
1853 jvf->print_lock_info_on(st, count);
1854 }
1855 } else {
1856 // Ignore non-Java frames
1857 }
1858
1859 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1860 count++;
1861 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1862 }
1863 }
1864
1865 void JavaThread::print_active_stack_on(outputStream* st) {
1866 if (is_vthread_mounted()) {
1867 print_vthread_stack_on(st);
1868 } else {
1869 print_stack_on(st);
1870 }
1871 }
1872
1873 #if INCLUDE_JVMTI
1874 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1875 JvmtiThreadState* JavaThread::rebind_to_jvmti_thread_state_of(oop thread_oop) {
1876 set_jvmti_vthread(thread_oop);
1877
1878 // unbind current JvmtiThreadState from JavaThread
1879 JvmtiThreadState::unbind_from(jvmti_thread_state(), this);
1880
1881 // bind new JvmtiThreadState to JavaThread
1882 JvmtiThreadState::bind_to(java_lang_Thread::jvmti_thread_state(thread_oop), this);
1883
1884 // enable interp_only_mode for virtual or carrier thread if it has pending bit
1885 JvmtiThreadState::process_pending_interp_only(this);
1886
1887 return jvmti_thread_state();
1888 }
1889 #endif
1890
1891 // JVMTI PopFrame support
1892 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
1893 assert(_popframe_preserved_args == nullptr, "should not wipe out old PopFrame preserved arguments");
1894 if (in_bytes(size_in_bytes) != 0) {
1895 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
1896 _popframe_preserved_args_size = in_bytes(size_in_bytes);
1897 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
1898 }
1899 }
1900
1901 void* JavaThread::popframe_preserved_args() {
1902 return _popframe_preserved_args;
1903 }
1904
1905 ByteSize JavaThread::popframe_preserved_args_size() {
1906 return in_ByteSize(_popframe_preserved_args_size);
1907 }
1908
1909 WordSize JavaThread::popframe_preserved_args_size_in_words() {
1910 int sz = in_bytes(popframe_preserved_args_size());
1911 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
1912 return in_WordSize(sz / wordSize);
1913 }
1914
1915 void JavaThread::popframe_free_preserved_args() {
1916 assert(_popframe_preserved_args != nullptr, "should not free PopFrame preserved arguments twice");
1917 FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
1918 _popframe_preserved_args = nullptr;
1919 _popframe_preserved_args_size = 0;
1920 }
1921
1922 #ifndef PRODUCT
1923
1924 void JavaThread::trace_frames() {
1925 tty->print_cr("[Describe stack]");
1926 int frame_no = 1;
1927 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1928 tty->print(" %d. ", frame_no++);
1929 fst.current()->print_value_on(tty);
1930 tty->cr();
1931 }
1932 }
1933
1934 class PrintAndVerifyOopClosure: public OopClosure {
1935 protected:
1936 template <class T> inline void do_oop_work(T* p) {
1937 oop obj = RawAccess<>::oop_load(p);
1938 if (obj == nullptr) return;
1939 tty->print(INTPTR_FORMAT ": ", p2i(p));
1940 if (oopDesc::is_oop_or_null(obj)) {
1941 if (obj->is_objArray()) {
1942 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
1943 } else {
1944 obj->print();
1945 }
1946 } else {
1947 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
1948 }
1949 tty->cr();
1950 }
1951 public:
1952 virtual void do_oop(oop* p) { do_oop_work(p); }
1953 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1954 };
1955
1956 #ifdef ASSERT
1957 // Print or validate the layout of stack frames
1958 void JavaThread::print_frame_layout(int depth, bool validate_only) {
1959 ResourceMark rm;
1960 PreserveExceptionMark pm(this);
1961 FrameValues values;
1962 int frame_no = 0;
1963 for (StackFrameStream fst(this, true, true, true); !fst.is_done(); fst.next()) {
1964 fst.current()->describe(values, ++frame_no, fst.register_map());
1965 if (depth == frame_no) break;
1966 }
1967 Continuation::describe(values);
1968 if (validate_only) {
1969 values.validate();
1970 } else {
1971 tty->print_cr("[Describe stack layout]");
1972 values.print(this);
1973 }
1974 }
1975 #endif
1976
1977 void JavaThread::trace_stack_from(vframe* start_vf) {
1978 ResourceMark rm;
1979 int vframe_no = 1;
1980 for (vframe* f = start_vf; f; f = f->sender()) {
1981 if (f->is_java_frame()) {
1982 javaVFrame::cast(f)->print_activation(vframe_no++);
1983 } else {
1984 f->print();
1985 }
1986 if (vframe_no > StackPrintLimit) {
1987 tty->print_cr("...<more frames>...");
1988 return;
1989 }
1990 }
1991 }
1992
1993
1994 void JavaThread::trace_stack() {
1995 if (!has_last_Java_frame()) return;
1996 Thread* current_thread = Thread::current();
1997 ResourceMark rm(current_thread);
1998 HandleMark hm(current_thread);
1999 RegisterMap reg_map(this,
2000 RegisterMap::UpdateMap::include,
2001 RegisterMap::ProcessFrames::include,
2002 RegisterMap::WalkContinuation::skip);
2003 trace_stack_from(last_java_vframe(®_map));
2004 }
2005
2006
2007 #endif // PRODUCT
2008
2009 // Slow-path increment of the held monitor counts. JNI locking is always
2010 // this slow-path.
2011 void JavaThread::inc_held_monitor_count(intx i, bool jni) {
2012 #ifdef SUPPORT_MONITOR_COUNT
2013
2014 if (LockingMode != LM_LEGACY) {
2015 // Nothing to do. Just do some sanity check.
2016 assert(_held_monitor_count == 0, "counter should not be used");
2017 assert(_jni_monitor_count == 0, "counter should not be used");
2018 return;
2019 }
2020
2021 assert(_held_monitor_count >= 0, "Must always be non-negative: %zd", _held_monitor_count);
2022 _held_monitor_count += i;
2023 if (jni) {
2024 assert(_jni_monitor_count >= 0, "Must always be non-negative: %zd", _jni_monitor_count);
2025 _jni_monitor_count += i;
2026 }
2027 assert(_held_monitor_count >= _jni_monitor_count, "Monitor count discrepancy detected - held count "
2028 "%zd is less than JNI count %zd", _held_monitor_count, _jni_monitor_count);
2029 #endif // SUPPORT_MONITOR_COUNT
2030 }
2031
2032 // Slow-path decrement of the held monitor counts. JNI unlocking is always
2033 // this slow-path.
2034 void JavaThread::dec_held_monitor_count(intx i, bool jni) {
2035 #ifdef SUPPORT_MONITOR_COUNT
2036
2037 if (LockingMode != LM_LEGACY) {
2038 // Nothing to do. Just do some sanity check.
2039 assert(_held_monitor_count == 0, "counter should not be used");
2040 assert(_jni_monitor_count == 0, "counter should not be used");
2041 return;
2042 }
2043
2044 _held_monitor_count -= i;
2045 assert(_held_monitor_count >= 0, "Must always be non-negative: %zd", _held_monitor_count);
2046 if (jni) {
2047 _jni_monitor_count -= i;
2048 assert(_jni_monitor_count >= 0, "Must always be non-negative: %zd", _jni_monitor_count);
2049 }
2050 // When a thread is detaching with still owned JNI monitors, the logic that releases
2051 // the monitors doesn't know to set the "jni" flag and so the counts can get out of sync.
2052 // So we skip this assert if the thread is exiting. Once all monitors are unlocked the
2053 // JNI count is directly set to zero.
2054 assert(_held_monitor_count >= _jni_monitor_count || is_exiting(), "Monitor count discrepancy detected - held count "
2055 "%zd is less than JNI count %zd", _held_monitor_count, _jni_monitor_count);
2056 #endif // SUPPORT_MONITOR_COUNT
2057 }
2058
2059 frame JavaThread::vthread_last_frame() {
2060 assert (is_vthread_mounted(), "Virtual thread not mounted");
2061 return last_frame();
2062 }
2063
2064 frame JavaThread::carrier_last_frame(RegisterMap* reg_map) {
2065 const ContinuationEntry* entry = vthread_continuation();
2066 guarantee (entry != nullptr, "Not a carrier thread");
2067 frame f = entry->to_frame();
2068 if (reg_map->process_frames()) {
2069 entry->flush_stack_processing(this);
2070 }
2071 entry->update_register_map(reg_map);
2072 return f.sender(reg_map);
2073 }
2074
2075 frame JavaThread::platform_thread_last_frame(RegisterMap* reg_map) {
2076 return is_vthread_mounted() ? carrier_last_frame(reg_map) : last_frame();
2077 }
2078
2079 javaVFrame* JavaThread::last_java_vframe(const frame f, RegisterMap *reg_map) {
2080 assert(reg_map != nullptr, "a map must be given");
2081 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
2082 if (vf->is_java_frame()) return javaVFrame::cast(vf);
2083 }
2084 return nullptr;
2085 }
2086
2087 Klass* JavaThread::security_get_caller_class(int depth) {
2088 ResetNoHandleMark rnhm;
2089 HandleMark hm(Thread::current());
2090
2091 vframeStream vfst(this);
2092 vfst.security_get_caller_frame(depth);
2093 if (!vfst.at_end()) {
2094 return vfst.method()->method_holder();
2095 }
2096 return nullptr;
2097 }
2098
2099 // Internal convenience function for millisecond resolution sleeps.
2100 bool JavaThread::sleep(jlong millis) {
2101 jlong nanos;
2102 if (millis > max_jlong / NANOUNITS_PER_MILLIUNIT) {
2103 // Conversion to nanos would overflow, saturate at max
2104 nanos = max_jlong;
2105 } else {
2106 nanos = millis * NANOUNITS_PER_MILLIUNIT;
2107 }
2108 return sleep_nanos(nanos);
2109 }
2110
2111 // java.lang.Thread.sleep support
2112 // Returns true if sleep time elapsed as expected, and false
2113 // if the thread was interrupted.
2114 bool JavaThread::sleep_nanos(jlong nanos) {
2115 assert(this == Thread::current(), "thread consistency check");
2116 assert(nanos >= 0, "nanos are in range");
2117
2118 ParkEvent * const slp = this->_SleepEvent;
2119 // Because there can be races with thread interruption sending an unpark()
2120 // to the event, we explicitly reset it here to avoid an immediate return.
2121 // The actual interrupt state will be checked before we park().
2122 slp->reset();
2123 // Thread interruption establishes a happens-before ordering in the
2124 // Java Memory Model, so we need to ensure we synchronize with the
2125 // interrupt state.
2126 OrderAccess::fence();
2127
2128 jlong prevtime = os::javaTimeNanos();
2129
2130 jlong nanos_remaining = nanos;
2131
2132 for (;;) {
2133 // interruption has precedence over timing out
2134 if (this->is_interrupted(true)) {
2135 return false;
2136 }
2137
2138 if (nanos_remaining <= 0) {
2139 return true;
2140 }
2141
2142 {
2143 ThreadBlockInVM tbivm(this);
2144 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
2145 slp->park_nanos(nanos_remaining);
2146 }
2147
2148 // Update elapsed time tracking
2149 jlong newtime = os::javaTimeNanos();
2150 if (newtime - prevtime < 0) {
2151 // time moving backwards, should only happen if no monotonic clock
2152 // not a guarantee() because JVM should not abort on kernel/glibc bugs
2153 assert(false,
2154 "unexpected time moving backwards detected in JavaThread::sleep()");
2155 } else {
2156 nanos_remaining -= (newtime - prevtime);
2157 }
2158 prevtime = newtime;
2159 }
2160 }
2161
2162 // Last thread running calls java.lang.Shutdown.shutdown()
2163 void JavaThread::invoke_shutdown_hooks() {
2164 HandleMark hm(this);
2165
2166 // We could get here with a pending exception, if so clear it now.
2167 if (this->has_pending_exception()) {
2168 this->clear_pending_exception();
2169 }
2170
2171 EXCEPTION_MARK;
2172 Klass* shutdown_klass =
2173 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
2174 THREAD);
2175 if (shutdown_klass != nullptr) {
2176 // SystemDictionary::resolve_or_null will return null if there was
2177 // an exception. If we cannot load the Shutdown class, just don't
2178 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
2179 // won't be run. Note that if a shutdown hook was registered,
2180 // the Shutdown class would have already been loaded
2181 // (Runtime.addShutdownHook will load it).
2182 JavaValue result(T_VOID);
2183 JavaCalls::call_static(&result,
2184 shutdown_klass,
2185 vmSymbols::shutdown_name(),
2186 vmSymbols::void_method_signature(),
2187 THREAD);
2188 }
2189 CLEAR_PENDING_EXCEPTION;
2190 }
2191
2192 #ifndef PRODUCT
2193 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
2194 report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
2195 }
2196 #endif
2197
2198 // Helper function to create the java.lang.Thread object for a
2199 // VM-internal thread. The thread will have the given name, and be
2200 // a member of the "system" ThreadGroup.
2201 Handle JavaThread::create_system_thread_object(const char* name, TRAPS) {
2202 Handle string = java_lang_String::create_from_str(name, CHECK_NH);
2203
2204 // Initialize thread_oop to put it into the system threadGroup.
2205 // This is done by calling the Thread(ThreadGroup group, String name) constructor.
2206 Handle thread_group(THREAD, Universe::system_thread_group());
2207 Handle thread_oop =
2208 JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
2209 vmSymbols::threadgroup_string_void_signature(),
2210 thread_group,
2211 string,
2212 CHECK_NH);
2213
2214 return thread_oop;
2215 }
2216
2217 // Starts the target JavaThread as a daemon of the given priority, and
2218 // bound to the given java.lang.Thread instance.
2219 // The Threads_lock is held for the duration.
2220 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
2221 Handle thread_oop, ThreadPriority prio) {
2222
2223 assert(target->osthread() != nullptr, "target thread is not properly initialized");
2224
2225 MutexLocker mu(current, Threads_lock);
2226
2227 // Initialize the fields of the thread_oop first.
2228 if (prio != NoPriority) {
2229 java_lang_Thread::set_priority(thread_oop(), prio);
2230 // Note: we don't call os::set_priority here. Possibly we should,
2231 // else all threads should call it themselves when they first run.
2232 }
2233
2234 java_lang_Thread::set_daemon(thread_oop());
2235
2236 // Now bind the thread_oop to the target JavaThread.
2237 target->set_threadOopHandles(thread_oop());
2238 target->set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
2239
2240 Threads::add(target); // target is now visible for safepoint/handshake
2241 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
2242 // on a ThreadsList. We don't want to wait for the release when the
2243 // Theads_lock is dropped when the 'mu' destructor is run since the
2244 // JavaThread* is already visible to JVM/TI via the ThreadsList.
2245
2246 assert(java_lang_Thread::thread(thread_oop()) == nullptr, "must not be alive");
2247 java_lang_Thread::release_set_thread(thread_oop(), target); // isAlive == true now
2248 Thread::start(target);
2249 }
2250
2251 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
2252 // At this point it may be possible that no osthread was created for the
2253 // JavaThread due to lack of resources. However, since this must work
2254 // for critical system threads just check and abort if this fails.
2255 if (thread->osthread() == nullptr) {
2256 // This isn't really an OOM condition, but historically this is what
2257 // we report.
2258 vm_exit_during_initialization("java.lang.OutOfMemoryError",
2259 os::native_thread_creation_failed_msg());
2260 }
2261 }
2262
2263 void JavaThread::pretouch_stack() {
2264 // Given an established java thread stack with usable area followed by
2265 // shadow zone and reserved/yellow/red zone, pretouch the usable area ranging
2266 // from the current frame down to the start of the shadow zone.
2267 const address end = _stack_overflow_state.shadow_zone_safe_limit();
2268 if (is_in_full_stack(end)) {
2269 char* p1 = (char*) alloca(1);
2270 address here = (address) &p1;
2271 if (is_in_full_stack(here) && here > end) {
2272 size_t to_alloc = here - end;
2273 char* p2 = (char*) alloca(to_alloc);
2274 log_trace(os, thread)("Pretouching thread stack for %zu: " RANGEFMT ".",
2275 (uintx) osthread()->thread_id(), RANGEFMTARGS(p2, to_alloc));
2276 os::pretouch_memory(p2, p2 + to_alloc,
2277 NOT_AIX(os::vm_page_size()) AIX_ONLY(4096));
2278 }
2279 }
2280 }
2281
2282 // Deferred OopHandle release support.
2283
2284 class OopHandleList : public CHeapObj<mtInternal> {
2285 static const int _count = 4;
2286 OopHandle _handles[_count];
2287 OopHandleList* _next;
2288 int _index;
2289 public:
2290 OopHandleList(OopHandleList* next) : _next(next), _index(0) {}
2291 void add(OopHandle h) {
2292 assert(_index < _count, "too many additions");
2293 _handles[_index++] = h;
2294 }
2295 ~OopHandleList() {
2296 assert(_index == _count, "usage error");
2297 for (int i = 0; i < _index; i++) {
2298 _handles[i].release(JavaThread::thread_oop_storage());
2299 }
2300 }
2301 OopHandleList* next() const { return _next; }
2302 };
2303
2304 OopHandleList* JavaThread::_oop_handle_list = nullptr;
2305
2306 // Called by the ServiceThread to do the work of releasing
2307 // the OopHandles.
2308 void JavaThread::release_oop_handles() {
2309 OopHandleList* list;
2310 {
2311 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2312 list = _oop_handle_list;
2313 _oop_handle_list = nullptr;
2314 }
2315 assert(!SafepointSynchronize::is_at_safepoint(), "cannot be called at a safepoint");
2316
2317 while (list != nullptr) {
2318 OopHandleList* l = list;
2319 list = l->next();
2320 delete l;
2321 }
2322 }
2323
2324 // Add our OopHandles for later release.
2325 void JavaThread::add_oop_handles_for_release() {
2326 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2327 OopHandleList* new_head = new OopHandleList(_oop_handle_list);
2328 new_head->add(_threadObj);
2329 new_head->add(_vthread);
2330 new_head->add(_jvmti_vthread);
2331 new_head->add(_scopedValueCache);
2332 _oop_handle_list = new_head;
2333 Service_lock->notify_all();
2334 }
2335
2336 #if INCLUDE_JFR
2337 void JavaThread::set_last_freeze_fail_result(freeze_result result) {
2338 assert(result != freeze_ok, "sanity check");
2339 _last_freeze_fail_result = result;
2340 _last_freeze_fail_time = Ticks::now();
2341 }
2342
2343 // Post jdk.VirtualThreadPinned event
2344 void JavaThread::post_vthread_pinned_event(EventVirtualThreadPinned* event, const char* op, freeze_result result) {
2345 assert(result != freeze_ok, "sanity check");
2346 if (event->should_commit()) {
2347 char reason[256];
2348 if (class_to_be_initialized() != nullptr) {
2349 ResourceMark rm(this);
2350 jio_snprintf(reason, sizeof reason, "Waited for initialization of %s by another thread",
2351 class_to_be_initialized()->external_name());
2352 event->set_pinnedReason(reason);
2353 } else if (class_being_initialized() != nullptr) {
2354 ResourceMark rm(this);
2355 jio_snprintf(reason, sizeof(reason), "VM call to %s.<clinit> on stack",
2356 class_being_initialized()->external_name());
2357 event->set_pinnedReason(reason);
2358 } else if (result == freeze_pinned_native) {
2359 event->set_pinnedReason("Native or VM frame on stack");
2360 } else {
2361 jio_snprintf(reason, sizeof(reason), "Freeze or preempt failed (%d)", result);
2362 event->set_pinnedReason(reason);
2363 }
2364 event->set_blockingOperation(op);
2365 event->set_carrierThread(JFR_JVM_THREAD_ID(this));
2366 event->commit();
2367 }
2368 }
2369 #endif