1 /*
2 * Copyright (c) 2003, 2024, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classLoaderDataGraph.hpp"
27 #include "classfile/javaClasses.inline.hpp"
28 #include "classfile/moduleEntry.hpp"
29 #include "classfile/symbolTable.hpp"
30 #include "classfile/vmSymbols.hpp"
31 #include "jvmtifiles/jvmtiEnv.hpp"
32 #include "memory/iterator.hpp"
33 #include "memory/resourceArea.hpp"
34 #include "oops/klass.inline.hpp"
35 #include "oops/objArrayKlass.hpp"
36 #include "oops/objArrayOop.hpp"
37 #include "oops/oop.inline.hpp"
38 #include "oops/oopHandle.inline.hpp"
39 #include "prims/jvmtiEnvBase.hpp"
40 #include "prims/jvmtiEventController.inline.hpp"
41 #include "prims/jvmtiExtensions.hpp"
42 #include "prims/jvmtiImpl.hpp"
43 #include "prims/jvmtiManageCapabilities.hpp"
44 #include "prims/jvmtiTagMap.hpp"
45 #include "prims/jvmtiThreadState.inline.hpp"
46 #include "runtime/continuationEntry.inline.hpp"
47 #include "runtime/deoptimization.hpp"
48 #include "runtime/frame.inline.hpp"
49 #include "runtime/handles.inline.hpp"
50 #include "runtime/interfaceSupport.inline.hpp"
51 #include "runtime/javaCalls.hpp"
52 #include "runtime/javaThread.inline.hpp"
53 #include "runtime/jfieldIDWorkaround.hpp"
54 #include "runtime/jniHandles.inline.hpp"
55 #include "runtime/objectMonitor.inline.hpp"
56 #include "runtime/osThread.hpp"
57 #include "runtime/signature.hpp"
58 #include "runtime/stackWatermarkSet.inline.hpp"
59 #include "runtime/threads.hpp"
60 #include "runtime/threadSMR.inline.hpp"
61 #include "runtime/vframe.inline.hpp"
62 #include "runtime/vframe_hp.hpp"
63 #include "runtime/vmThread.hpp"
64 #include "runtime/vmOperations.hpp"
65 #include "services/threadService.hpp"
66
67
68 ///////////////////////////////////////////////////////////////
69 //
70 // JvmtiEnvBase
71 //
72
73 JvmtiEnvBase* JvmtiEnvBase::_head_environment = nullptr;
74
75 bool JvmtiEnvBase::_globally_initialized = false;
76 volatile bool JvmtiEnvBase::_needs_clean_up = false;
77
78 jvmtiPhase JvmtiEnvBase::_phase = JVMTI_PHASE_PRIMORDIAL;
79
80 volatile int JvmtiEnvBase::_dying_thread_env_iteration_count = 0;
81
82 extern jvmtiInterface_1_ jvmti_Interface;
83 extern jvmtiInterface_1_ jvmtiTrace_Interface;
84
85
86 // perform initializations that must occur before any JVMTI environments
87 // are released but which should only be initialized once (no matter
88 // how many environments are created).
89 void
90 JvmtiEnvBase::globally_initialize() {
91 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
92 assert(_globally_initialized == false, "bad call");
93
94 JvmtiManageCapabilities::initialize();
95
96 // register extension functions and events
97 JvmtiExtensions::register_extensions();
98
99 #ifdef JVMTI_TRACE
100 JvmtiTrace::initialize();
101 #endif
102
103 _globally_initialized = true;
104 }
105
106
107 void
108 JvmtiEnvBase::initialize() {
109 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
110
111 // Add this environment to the end of the environment list (order is important)
112 {
113 // This block of code must not contain any safepoints, as list deallocation
114 // (which occurs at a safepoint) cannot occur simultaneously with this list
115 // addition. Note: NoSafepointVerifier cannot, currently, be used before
116 // threads exist.
117 JvmtiEnvIterator it;
118 JvmtiEnvBase *previous_env = nullptr;
119 for (JvmtiEnvBase* env = it.first(); env != nullptr; env = it.next(env)) {
120 previous_env = env;
121 }
122 if (previous_env == nullptr) {
123 _head_environment = this;
124 } else {
125 previous_env->set_next_environment(this);
126 }
127 }
128
129 if (_globally_initialized == false) {
130 globally_initialize();
131 }
132 }
133
134 jvmtiPhase
135 JvmtiEnvBase::phase() {
136 // For the JVMTI environments possessed the can_generate_early_vmstart:
137 // replace JVMTI_PHASE_PRIMORDIAL with JVMTI_PHASE_START
138 if (_phase == JVMTI_PHASE_PRIMORDIAL &&
139 JvmtiExport::early_vmstart_recorded() &&
140 early_vmstart_env()) {
141 return JVMTI_PHASE_START;
142 }
143 return _phase; // Normal case
144 }
145
146 bool
147 JvmtiEnvBase::is_valid() {
148 jlong value = 0;
149
150 // This object might not be a JvmtiEnvBase so we can't assume
151 // the _magic field is properly aligned. Get the value in a safe
152 // way and then check against JVMTI_MAGIC.
153
154 switch (sizeof(_magic)) {
155 case 2:
156 value = Bytes::get_native_u2((address)&_magic);
157 break;
158
159 case 4:
160 value = Bytes::get_native_u4((address)&_magic);
161 break;
162
163 case 8:
164 value = Bytes::get_native_u8((address)&_magic);
165 break;
166
167 default:
168 guarantee(false, "_magic field is an unexpected size");
169 }
170
171 return value == JVMTI_MAGIC;
172 }
173
174
175 bool
176 JvmtiEnvBase::use_version_1_0_semantics() {
177 int major, minor, micro;
178
179 JvmtiExport::decode_version_values(_version, &major, &minor, µ);
180 return major == 1 && minor == 0; // micro version doesn't matter here
181 }
182
183
184 bool
185 JvmtiEnvBase::use_version_1_1_semantics() {
186 int major, minor, micro;
187
188 JvmtiExport::decode_version_values(_version, &major, &minor, µ);
189 return major == 1 && minor == 1; // micro version doesn't matter here
190 }
191
192 bool
193 JvmtiEnvBase::use_version_1_2_semantics() {
194 int major, minor, micro;
195
196 JvmtiExport::decode_version_values(_version, &major, &minor, µ);
197 return major == 1 && minor == 2; // micro version doesn't matter here
198 }
199
200
201 JvmtiEnvBase::JvmtiEnvBase(jint version) : _env_event_enable() {
202 _version = version;
203 _env_local_storage = nullptr;
204 _tag_map = nullptr;
205 _native_method_prefix_count = 0;
206 _native_method_prefixes = nullptr;
207 _next = nullptr;
208 _class_file_load_hook_ever_enabled = false;
209
210 // Moot since ClassFileLoadHook not yet enabled.
211 // But "true" will give a more predictable ClassFileLoadHook behavior
212 // for environment creation during ClassFileLoadHook.
213 _is_retransformable = true;
214
215 // all callbacks initially null
216 memset(&_event_callbacks, 0, sizeof(jvmtiEventCallbacks));
217 memset(&_ext_event_callbacks, 0, sizeof(jvmtiExtEventCallbacks));
218
219 // all capabilities initially off
220 memset(&_current_capabilities, 0, sizeof(_current_capabilities));
221
222 // all prohibited capabilities initially off
223 memset(&_prohibited_capabilities, 0, sizeof(_prohibited_capabilities));
224
225 _magic = JVMTI_MAGIC;
226
227 JvmtiEventController::env_initialize((JvmtiEnv*)this);
228
229 #ifdef JVMTI_TRACE
230 _jvmti_external.functions = TraceJVMTI != nullptr ? &jvmtiTrace_Interface : &jvmti_Interface;
231 #else
232 _jvmti_external.functions = &jvmti_Interface;
233 #endif
234 }
235
236
237 void
238 JvmtiEnvBase::dispose() {
239
240 #ifdef JVMTI_TRACE
241 JvmtiTrace::shutdown();
242 #endif
243
244 // Dispose of event info and let the event controller call us back
245 // in a locked state (env_dispose, below)
246 JvmtiEventController::env_dispose(this);
247 }
248
249 void
250 JvmtiEnvBase::env_dispose() {
251 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
252
253 // We have been entered with all events disabled on this environment.
254 // A race to re-enable events (by setting callbacks) is prevented by
255 // checking for a valid environment when setting callbacks (while
256 // holding the JvmtiThreadState_lock).
257
258 // Mark as invalid.
259 _magic = DISPOSED_MAGIC;
260
261 // Relinquish all capabilities.
262 jvmtiCapabilities *caps = get_capabilities();
263 JvmtiManageCapabilities::relinquish_capabilities(caps, caps, caps);
264
265 // Same situation as with events (see above)
266 set_native_method_prefixes(0, nullptr);
267
268 JvmtiTagMap* tag_map_to_clear = tag_map_acquire();
269 // A tag map can be big, clear it now to save memory until
270 // the destructor runs.
271 if (tag_map_to_clear != nullptr) {
272 tag_map_to_clear->clear();
273 }
274
275 _needs_clean_up = true;
276 }
277
278
279 JvmtiEnvBase::~JvmtiEnvBase() {
280 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
281
282 // There is a small window of time during which the tag map of a
283 // disposed environment could have been reallocated.
284 // Make sure it is gone.
285 JvmtiTagMap* tag_map_to_deallocate = _tag_map;
286 set_tag_map(nullptr);
287 // A tag map can be big, deallocate it now
288 if (tag_map_to_deallocate != nullptr) {
289 delete tag_map_to_deallocate;
290 }
291
292 _magic = BAD_MAGIC;
293 }
294
295
296 void
297 JvmtiEnvBase::periodic_clean_up() {
298 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
299
300 // JvmtiEnvBase reference is saved in JvmtiEnvThreadState. So
301 // clean up JvmtiThreadState before deleting JvmtiEnv pointer.
302 JvmtiThreadState::periodic_clean_up();
303
304 // Unlink all invalid environments from the list of environments
305 // and deallocate them
306 JvmtiEnvIterator it;
307 JvmtiEnvBase* previous_env = nullptr;
308 JvmtiEnvBase* env = it.first();
309 while (env != nullptr) {
310 if (env->is_valid()) {
311 previous_env = env;
312 env = it.next(env);
313 } else {
314 // This one isn't valid, remove it from the list and deallocate it
315 JvmtiEnvBase* defunct_env = env;
316 env = it.next(env);
317 if (previous_env == nullptr) {
318 _head_environment = env;
319 } else {
320 previous_env->set_next_environment(env);
321 }
322 delete defunct_env;
323 }
324 }
325
326 }
327
328
329 void
330 JvmtiEnvBase::check_for_periodic_clean_up() {
331 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
332
333 class ThreadInsideIterationClosure: public ThreadClosure {
334 private:
335 bool _inside;
336 public:
337 ThreadInsideIterationClosure() : _inside(false) {};
338
339 void do_thread(Thread* thread) {
340 _inside |= thread->is_inside_jvmti_env_iteration();
341 }
342
343 bool is_inside_jvmti_env_iteration() {
344 return _inside;
345 }
346 };
347
348 if (_needs_clean_up) {
349 // Check if we are currently iterating environment,
350 // deallocation should not occur if we are
351 ThreadInsideIterationClosure tiic;
352 Threads::threads_do(&tiic);
353 if (!tiic.is_inside_jvmti_env_iteration() &&
354 !is_inside_dying_thread_env_iteration()) {
355 _needs_clean_up = false;
356 JvmtiEnvBase::periodic_clean_up();
357 }
358 }
359 }
360
361
362 void
363 JvmtiEnvBase::record_first_time_class_file_load_hook_enabled() {
364 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(),
365 "sanity check");
366
367 if (!_class_file_load_hook_ever_enabled) {
368 _class_file_load_hook_ever_enabled = true;
369
370 if (get_capabilities()->can_retransform_classes) {
371 _is_retransformable = true;
372 } else {
373 _is_retransformable = false;
374
375 // cannot add retransform capability after ClassFileLoadHook has been enabled
376 get_prohibited_capabilities()->can_retransform_classes = 1;
377 }
378 }
379 }
380
381
382 void
383 JvmtiEnvBase::record_class_file_load_hook_enabled() {
384 if (!_class_file_load_hook_ever_enabled) {
385 if (Threads::number_of_threads() == 0) {
386 record_first_time_class_file_load_hook_enabled();
387 } else {
388 MutexLocker mu(JvmtiThreadState_lock);
389 record_first_time_class_file_load_hook_enabled();
390 }
391 }
392 }
393
394
395 jvmtiError
396 JvmtiEnvBase::set_native_method_prefixes(jint prefix_count, char** prefixes) {
397 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(),
398 "sanity check");
399
400 int old_prefix_count = get_native_method_prefix_count();
401 char **old_prefixes = get_native_method_prefixes();
402
403 // allocate and install the new prefixex
404 if (prefix_count == 0 || !is_valid()) {
405 _native_method_prefix_count = 0;
406 _native_method_prefixes = nullptr;
407 } else {
408 // there are prefixes, allocate an array to hold them, and fill it
409 char** new_prefixes = (char**)os::malloc((prefix_count) * sizeof(char*), mtInternal);
410 if (new_prefixes == nullptr) {
411 return JVMTI_ERROR_OUT_OF_MEMORY;
412 }
413 for (int i = 0; i < prefix_count; i++) {
414 char* prefix = prefixes[i];
415 if (prefix == nullptr) {
416 for (int j = 0; j < (i-1); j++) {
417 os::free(new_prefixes[j]);
418 }
419 os::free(new_prefixes);
420 return JVMTI_ERROR_NULL_POINTER;
421 }
422 prefix = os::strdup(prefixes[i]);
423 if (prefix == nullptr) {
424 for (int j = 0; j < (i-1); j++) {
425 os::free(new_prefixes[j]);
426 }
427 os::free(new_prefixes);
428 return JVMTI_ERROR_OUT_OF_MEMORY;
429 }
430 new_prefixes[i] = prefix;
431 }
432 _native_method_prefix_count = prefix_count;
433 _native_method_prefixes = new_prefixes;
434 }
435
436 // now that we know the new prefixes have been successfully installed we can
437 // safely remove the old ones
438 if (old_prefix_count != 0) {
439 for (int i = 0; i < old_prefix_count; i++) {
440 os::free(old_prefixes[i]);
441 }
442 os::free(old_prefixes);
443 }
444
445 return JVMTI_ERROR_NONE;
446 }
447
448
449 // Collect all the prefixes which have been set in any JVM TI environments
450 // by the SetNativeMethodPrefix(es) functions. Be sure to maintain the
451 // order of environments and the order of prefixes within each environment.
452 // Return in a resource allocated array.
453 char**
454 JvmtiEnvBase::get_all_native_method_prefixes(int* count_ptr) {
455 assert(Threads::number_of_threads() == 0 ||
456 SafepointSynchronize::is_at_safepoint() ||
457 JvmtiThreadState_lock->is_locked(),
458 "sanity check");
459
460 int total_count = 0;
461 GrowableArray<char*>* prefix_array =new GrowableArray<char*>(5);
462
463 JvmtiEnvIterator it;
464 for (JvmtiEnvBase* env = it.first(); env != nullptr; env = it.next(env)) {
465 int prefix_count = env->get_native_method_prefix_count();
466 char** prefixes = env->get_native_method_prefixes();
467 for (int j = 0; j < prefix_count; j++) {
468 // retrieve a prefix and so that it is safe against asynchronous changes
469 // copy it into the resource area
470 char* prefix = prefixes[j];
471 char* prefix_copy = NEW_RESOURCE_ARRAY(char, strlen(prefix)+1);
472 strcpy(prefix_copy, prefix);
473 prefix_array->at_put_grow(total_count++, prefix_copy);
474 }
475 }
476
477 char** all_prefixes = NEW_RESOURCE_ARRAY(char*, total_count);
478 char** p = all_prefixes;
479 for (int i = 0; i < total_count; ++i) {
480 *p++ = prefix_array->at(i);
481 }
482 *count_ptr = total_count;
483 return all_prefixes;
484 }
485
486 void
487 JvmtiEnvBase::set_event_callbacks(const jvmtiEventCallbacks* callbacks,
488 jint size_of_callbacks) {
489 assert(Threads::number_of_threads() == 0 || JvmtiThreadState_lock->is_locked(), "sanity check");
490
491 size_t byte_cnt = sizeof(jvmtiEventCallbacks);
492
493 // clear in either case to be sure we got any gap between sizes
494 memset(&_event_callbacks, 0, byte_cnt);
495
496 // Now that JvmtiThreadState_lock is held, prevent a possible race condition where events
497 // are re-enabled by a call to set event callbacks where the DisposeEnvironment
498 // occurs after the boiler-plate environment check and before the lock is acquired.
499 if (callbacks != nullptr && is_valid()) {
500 if (size_of_callbacks < (jint)byte_cnt) {
501 byte_cnt = size_of_callbacks;
502 }
503 memcpy(&_event_callbacks, callbacks, byte_cnt);
504 }
505 }
506
507
508 // In the fullness of time, all users of the method should instead
509 // directly use allocate, besides being cleaner and faster, this will
510 // mean much better out of memory handling
511 unsigned char *
512 JvmtiEnvBase::jvmtiMalloc(jlong size) {
513 unsigned char* mem = nullptr;
514 jvmtiError result = allocate(size, &mem);
515 assert(result == JVMTI_ERROR_NONE, "Allocate failed");
516 return mem;
517 }
518
519
520 // Handle management
521
522 jobject JvmtiEnvBase::jni_reference(Handle hndl) {
523 return JNIHandles::make_local(hndl());
524 }
525
526 jobject JvmtiEnvBase::jni_reference(JavaThread *thread, Handle hndl) {
527 return JNIHandles::make_local(thread, hndl());
528 }
529
530 void JvmtiEnvBase::destroy_jni_reference(jobject jobj) {
531 JNIHandles::destroy_local(jobj);
532 }
533
534 void JvmtiEnvBase::destroy_jni_reference(JavaThread *thread, jobject jobj) {
535 JNIHandles::destroy_local(jobj); // thread is unused.
536 }
537
538 //
539 // Threads
540 //
541
542 jthread *
543 JvmtiEnvBase::new_jthreadArray(int length, Handle *handles) {
544 if (length == 0) {
545 return nullptr;
546 }
547
548 jthread* objArray = (jthread *) jvmtiMalloc(sizeof(jthread) * length);
549 NULL_CHECK(objArray, nullptr);
550
551 for (int i = 0; i < length; i++) {
552 objArray[i] = (jthread)jni_reference(handles[i]);
553 }
554 return objArray;
555 }
556
557 jthreadGroup *
558 JvmtiEnvBase::new_jthreadGroupArray(int length, objArrayHandle groups) {
559 if (length == 0) {
560 return nullptr;
561 }
562
563 jthreadGroup* objArray = (jthreadGroup *) jvmtiMalloc(sizeof(jthreadGroup) * length);
564 NULL_CHECK(objArray, nullptr);
565
566 for (int i = 0; i < length; i++) {
567 objArray[i] = (jthreadGroup)JNIHandles::make_local(groups->obj_at(i));
568 }
569 return objArray;
570 }
571
572 // Return the vframe on the specified thread and depth, null if no such frame.
573 // The thread and the oops in the returned vframe might not have been processed.
574 javaVFrame*
575 JvmtiEnvBase::jvf_for_thread_and_depth(JavaThread* java_thread, jint depth) {
576 if (!java_thread->has_last_Java_frame()) {
577 return nullptr;
578 }
579 RegisterMap reg_map(java_thread,
580 RegisterMap::UpdateMap::include,
581 RegisterMap::ProcessFrames::skip,
582 RegisterMap::WalkContinuation::include);
583 javaVFrame *jvf = java_thread->last_java_vframe(®_map);
584
585 jvf = JvmtiEnvBase::check_and_skip_hidden_frames(java_thread, jvf);
586
587 for (int d = 0; jvf != nullptr && d < depth; d++) {
588 jvf = jvf->java_sender();
589 }
590 return jvf;
591 }
592
593 //
594 // utilities: JNI objects
595 //
596
597
598 jclass
599 JvmtiEnvBase::get_jni_class_non_null(Klass* k) {
600 assert(k != nullptr, "k != null");
601 Thread *thread = Thread::current();
602 return (jclass)jni_reference(Handle(thread, k->java_mirror()));
603 }
604
605 //
606 // Field Information
607 //
608
609 bool
610 JvmtiEnvBase::get_field_descriptor(Klass* k, jfieldID field, fieldDescriptor* fd) {
611 if (!jfieldIDWorkaround::is_valid_jfieldID(k, field)) {
612 return false;
613 }
614 bool found = false;
615 if (jfieldIDWorkaround::is_static_jfieldID(field)) {
616 JNIid* id = jfieldIDWorkaround::from_static_jfieldID(field);
617 found = id->find_local_field(fd);
618 } else {
619 // Non-static field. The fieldID is really the offset of the field within the object.
620 int offset = jfieldIDWorkaround::from_instance_jfieldID(k, field);
621 found = InstanceKlass::cast(k)->find_field_from_offset(offset, false, fd);
622 }
623 return found;
624 }
625
626 bool
627 JvmtiEnvBase::is_vthread_alive(oop vt) {
628 oop cont = java_lang_VirtualThread::continuation(vt);
629 return !jdk_internal_vm_Continuation::done(cont) &&
630 java_lang_VirtualThread::state(vt) != java_lang_VirtualThread::NEW;
631 }
632
633 // Return JavaThread if virtual thread is mounted, null otherwise.
634 JavaThread* JvmtiEnvBase::get_JavaThread_or_null(oop vthread) {
635 oop carrier_thread = java_lang_VirtualThread::carrier_thread(vthread);
636 if (carrier_thread == nullptr) {
637 return nullptr;
638 }
639
640 JavaThread* java_thread = java_lang_Thread::thread(carrier_thread);
641
642 // This could be a different thread to the current one. So we need to ensure that
643 // processing has started before we are allowed to read the continuation oop of
644 // another thread, as it is a direct root of that other thread.
645 StackWatermarkSet::start_processing(java_thread, StackWatermarkKind::gc);
646
647 oop cont = java_lang_VirtualThread::continuation(vthread);
648 assert(cont != nullptr, "must be");
649 assert(Continuation::continuation_scope(cont) == java_lang_VirtualThread::vthread_scope(), "must be");
650 return Continuation::is_continuation_mounted(java_thread, cont) ? java_thread : nullptr;
651 }
652
653 javaVFrame*
654 JvmtiEnvBase::check_and_skip_hidden_frames(bool is_in_VTMS_transition, javaVFrame* jvf) {
655 // The second condition is needed to hide notification methods.
656 if (!is_in_VTMS_transition && (jvf == nullptr || !jvf->method()->jvmti_mount_transition())) {
657 return jvf; // No frames to skip.
658 }
659 // Find jvf with a method annotated with @JvmtiMountTransition.
660 for ( ; jvf != nullptr; jvf = jvf->java_sender()) {
661 if (jvf->method()->jvmti_mount_transition()) { // Cannot actually appear in an unmounted continuation; they're never frozen.
662 jvf = jvf->java_sender(); // Skip annotated method.
663 break;
664 }
665 if (jvf->method()->changes_current_thread()) {
666 break;
667 }
668 // Skip frame above annotated method.
669 }
670 return jvf;
671 }
672
673 javaVFrame*
674 JvmtiEnvBase::check_and_skip_hidden_frames(JavaThread* jt, javaVFrame* jvf) {
675 jvf = check_and_skip_hidden_frames(jt->is_in_VTMS_transition(), jvf);
676 return jvf;
677 }
678
679 javaVFrame*
680 JvmtiEnvBase::check_and_skip_hidden_frames(oop vthread, javaVFrame* jvf) {
681 JvmtiThreadState* state = java_lang_Thread::jvmti_thread_state(vthread);
682 if (state == nullptr) {
683 // nothing to skip
684 return jvf;
685 }
686 jvf = check_and_skip_hidden_frames(java_lang_Thread::is_in_VTMS_transition(vthread), jvf);
687 return jvf;
688 }
689
690 javaVFrame*
691 JvmtiEnvBase::get_vthread_jvf(oop vthread) {
692 assert(java_lang_VirtualThread::state(vthread) != java_lang_VirtualThread::NEW, "sanity check");
693 assert(java_lang_VirtualThread::state(vthread) != java_lang_VirtualThread::TERMINATED, "sanity check");
694
695 Thread* cur_thread = Thread::current();
696 oop cont = java_lang_VirtualThread::continuation(vthread);
697 javaVFrame* jvf = nullptr;
698
699 JavaThread* java_thread = get_JavaThread_or_null(vthread);
700 if (java_thread != nullptr) {
701 if (!java_thread->has_last_Java_frame()) {
702 // TBD: This is a temporary work around to avoid a guarantee caused by
703 // the native enterSpecial frame on the top. No frames will be found
704 // by the JVMTI functions such as GetStackTrace.
705 return nullptr;
706 }
707 vframeStream vfs(java_thread);
708 jvf = vfs.at_end() ? nullptr : vfs.asJavaVFrame();
709 jvf = check_and_skip_hidden_frames(java_thread, jvf);
710 } else {
711 vframeStream vfs(cont);
712 jvf = vfs.at_end() ? nullptr : vfs.asJavaVFrame();
713 jvf = check_and_skip_hidden_frames(vthread, jvf);
714 }
715 return jvf;
716 }
717
718 // Return correct javaVFrame for a carrier (non-virtual) thread.
719 // It strips vthread frames at the top if there are any.
720 javaVFrame*
721 JvmtiEnvBase::get_cthread_last_java_vframe(JavaThread* jt, RegisterMap* reg_map_p) {
722 // Strip vthread frames in case of carrier thread with mounted continuation.
723 bool cthread_with_cont = JvmtiEnvBase::is_cthread_with_continuation(jt);
724 javaVFrame *jvf = cthread_with_cont ? jt->carrier_last_java_vframe(reg_map_p)
725 : jt->last_java_vframe(reg_map_p);
726 // Skip hidden frames only for carrier threads
727 // which are in non-temporary VTMS transition.
728 if (jt->is_in_VTMS_transition()) {
729 jvf = check_and_skip_hidden_frames(jt, jvf);
730 }
731 return jvf;
732 }
733
734 jint
735 JvmtiEnvBase::get_thread_state_base(oop thread_oop, JavaThread* jt) {
736 jint state = 0;
737
738 if (thread_oop != nullptr) {
739 // Get most state bits.
740 state = (jint)java_lang_Thread::get_thread_status(thread_oop);
741 }
742 if (jt != nullptr) {
743 // We have a JavaThread* so add more state bits.
744 JavaThreadState jts = jt->thread_state();
745
746 if (jt->is_carrier_thread_suspended() ||
747 ((jt->jvmti_vthread() == nullptr || jt->jvmti_vthread() == thread_oop) && jt->is_suspended())) {
748 // Suspended non-virtual thread.
749 state |= JVMTI_THREAD_STATE_SUSPENDED;
750 }
751 if (jts == _thread_in_native) {
752 state |= JVMTI_THREAD_STATE_IN_NATIVE;
753 }
754 if (jt->is_interrupted(false)) {
755 state |= JVMTI_THREAD_STATE_INTERRUPTED;
756 }
757 }
758 return state;
759 }
760
761 jint
762 JvmtiEnvBase::get_thread_state(oop thread_oop, JavaThread* jt) {
763 jint state = 0;
764
765 if (is_thread_carrying_vthread(jt, thread_oop)) {
766 state = (jint)java_lang_Thread::get_thread_status(thread_oop);
767
768 // This is for extra safety. Other bits are not expected nor needed.
769 state &= (JVMTI_THREAD_STATE_ALIVE | JVMTI_THREAD_STATE_INTERRUPTED);
770
771 if (jt->is_carrier_thread_suspended()) {
772 state |= JVMTI_THREAD_STATE_SUSPENDED;
773 }
774 // It's okay for the JVMTI state to be reported as WAITING when waiting
775 // for something other than an Object.wait. So, we treat a thread carrying
776 // a virtual thread as waiting indefinitely which is not runnable.
777 // It is why the RUNNABLE bit is not needed and the WAITING bits are added.
778 state |= JVMTI_THREAD_STATE_WAITING | JVMTI_THREAD_STATE_WAITING_INDEFINITELY;
779 } else {
780 state = get_thread_state_base(thread_oop, jt);
781 }
782 return state;
783 }
784
785 jint
786 JvmtiEnvBase::get_vthread_state(oop thread_oop, JavaThread* java_thread) {
787 jint state = 0;
788 bool is_mon_responsible = java_lang_VirtualThread::recheckInterval(thread_oop) > 0;
789 bool ext_suspended = JvmtiVTSuspender::is_vthread_suspended(thread_oop);
790 jint interrupted = java_lang_Thread::interrupted(thread_oop);
791
792 if (java_thread != nullptr) {
793 // If virtual thread is blocked on a monitor enter the BLOCKED_ON_MONITOR_ENTER bit
794 // is set for carrier thread instead of virtual.
795 // Other state bits except filtered ones are expected to be the same.
796 oop ct_oop = java_lang_VirtualThread::carrier_thread(thread_oop);
797 jint filtered_bits = JVMTI_THREAD_STATE_SUSPENDED | JVMTI_THREAD_STATE_INTERRUPTED;
798
799 // This call can trigger a safepoint, so thread_oop must not be used after it.
800 state = get_thread_state_base(ct_oop, java_thread) & ~filtered_bits;
801 } else if (is_mon_responsible) {
802 state = (jint) JavaThreadStatus::BLOCKED_ON_MONITOR_ENTER;
803 } else {
804 int vt_state = java_lang_VirtualThread::state(thread_oop);
805 state = (jint)java_lang_VirtualThread::map_state_to_thread_status(vt_state);
806 }
807 // Ensure the thread has not exited after retrieving suspended/interrupted values.
808 if ((state & JVMTI_THREAD_STATE_ALIVE) != 0) {
809 if (ext_suspended) {
810 state |= JVMTI_THREAD_STATE_SUSPENDED;
811 }
812 if (interrupted) {
813 state |= JVMTI_THREAD_STATE_INTERRUPTED;
814 }
815 }
816 return state;
817 }
818
819 jint
820 JvmtiEnvBase::get_thread_or_vthread_state(oop thread_oop, JavaThread* java_thread) {
821 jint state = 0;
822 if (java_lang_VirtualThread::is_instance(thread_oop)) {
823 state = JvmtiEnvBase::get_vthread_state(thread_oop, java_thread);
824 } else {
825 state = JvmtiEnvBase::get_thread_state(thread_oop, java_thread);
826 }
827 return state;
828 }
829
830 jvmtiError
831 JvmtiEnvBase::get_live_threads(JavaThread* current_thread, Handle group_hdl, jint *count_ptr, Handle **thread_objs_p) {
832 jint count = 0;
833 Handle *thread_objs = nullptr;
834 ThreadsListEnumerator tle(current_thread, /* include_jvmti_agent_threads */ true);
835 int nthreads = tle.num_threads();
836 if (nthreads > 0) {
837 thread_objs = NEW_RESOURCE_ARRAY_RETURN_NULL(Handle, nthreads);
838 NULL_CHECK(thread_objs, JVMTI_ERROR_OUT_OF_MEMORY);
839 for (int i = 0; i < nthreads; i++) {
840 Handle thread = tle.get_threadObj(i);
841 if (thread()->is_a(vmClasses::Thread_klass()) && java_lang_Thread::threadGroup(thread()) == group_hdl()) {
842 thread_objs[count++] = thread;
843 }
844 }
845 }
846 *thread_objs_p = thread_objs;
847 *count_ptr = count;
848 return JVMTI_ERROR_NONE;
849 }
850
851 jvmtiError
852 JvmtiEnvBase::get_subgroups(JavaThread* current_thread, Handle group_hdl, jint *count_ptr, objArrayHandle *group_objs_p) {
853
854 // This call collects the strong and weak groups
855 JavaThread* THREAD = current_thread;
856 JavaValue result(T_OBJECT);
857 JavaCalls::call_virtual(&result,
858 group_hdl,
859 vmClasses::ThreadGroup_klass(),
860 SymbolTable::new_permanent_symbol("subgroupsAsArray"),
861 vmSymbols::void_threadgroup_array_signature(),
862 THREAD);
863 if (HAS_PENDING_EXCEPTION) {
864 Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
865 CLEAR_PENDING_EXCEPTION;
866 if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
867 return JVMTI_ERROR_OUT_OF_MEMORY;
868 } else {
869 return JVMTI_ERROR_INTERNAL;
870 }
871 }
872
873 assert(result.get_type() == T_OBJECT, "just checking");
874 objArrayOop groups = (objArrayOop)result.get_oop();
875
876 *count_ptr = groups == nullptr ? 0 : groups->length();
877 *group_objs_p = objArrayHandle(current_thread, groups);
878
879 return JVMTI_ERROR_NONE;
880 }
881
882 //
883 // Object Monitor Information
884 //
885
886 //
887 // Count the number of objects for a lightweight monitor. The hobj
888 // parameter is object that owns the monitor so this routine will
889 // count the number of times the same object was locked by frames
890 // in java_thread.
891 //
892 jint
893 JvmtiEnvBase::count_locked_objects(JavaThread *java_thread, Handle hobj) {
894 jint ret = 0;
895 if (!java_thread->has_last_Java_frame()) {
896 return ret; // no Java frames so no monitors
897 }
898
899 Thread* current_thread = Thread::current();
900 ResourceMark rm(current_thread);
901 HandleMark hm(current_thread);
902 RegisterMap reg_map(java_thread,
903 RegisterMap::UpdateMap::include,
904 RegisterMap::ProcessFrames::include,
905 RegisterMap::WalkContinuation::skip);
906
907 for (javaVFrame *jvf = java_thread->last_java_vframe(®_map); jvf != nullptr;
908 jvf = jvf->java_sender()) {
909 GrowableArray<MonitorInfo*>* mons = jvf->monitors();
910 if (!mons->is_empty()) {
911 for (int i = 0; i < mons->length(); i++) {
912 MonitorInfo *mi = mons->at(i);
913 if (mi->owner_is_scalar_replaced()) continue;
914
915 // see if owner of the monitor is our object
916 if (mi->owner() != nullptr && mi->owner() == hobj()) {
917 ret++;
918 }
919 }
920 }
921 }
922 return ret;
923 }
924
925 jvmtiError
926 JvmtiEnvBase::get_current_contended_monitor(JavaThread *calling_thread, JavaThread *java_thread,
927 jobject *monitor_ptr, bool is_virtual) {
928 Thread *current_thread = Thread::current();
929 assert(java_thread->is_handshake_safe_for(current_thread),
930 "call by myself or at handshake");
931 if (!is_virtual && JvmtiEnvBase::is_cthread_with_continuation(java_thread)) {
932 // Carrier thread with a mounted continuation case.
933 // No contended monitor can be owned by carrier thread in this case.
934 *monitor_ptr = nullptr;
935 return JVMTI_ERROR_NONE;
936 }
937 oop obj = nullptr;
938 // The ObjectMonitor* can't be async deflated since we are either
939 // at a safepoint or the calling thread is operating on itself so
940 // it cannot leave the underlying wait()/enter() call.
941 ObjectMonitor *mon = java_thread->current_waiting_monitor();
942 if (mon == nullptr) {
943 // thread is not doing an Object.wait() call
944 mon = java_thread->current_pending_monitor();
945 if (mon != nullptr) {
946 // The thread is trying to enter() an ObjectMonitor.
947 obj = mon->object();
948 assert(obj != nullptr, "ObjectMonitor should have a valid object!");
949 }
950 } else {
951 // thread is doing an Object.wait() call
952 oop thread_oop = get_vthread_or_thread_oop(java_thread);
953 jint state = get_thread_or_vthread_state(thread_oop, java_thread);
954
955 if (state & JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER) {
956 // thread is re-entering the monitor in an Object.wait() call
957 obj = mon->object();
958 assert(obj != nullptr, "Object.wait() should have an object");
959 }
960 }
961
962 if (obj == nullptr) {
963 *monitor_ptr = nullptr;
964 } else {
965 HandleMark hm(current_thread);
966 Handle hobj(current_thread, obj);
967 *monitor_ptr = jni_reference(calling_thread, hobj);
968 }
969 return JVMTI_ERROR_NONE;
970 }
971
972 jvmtiError
973 JvmtiEnvBase::get_owned_monitors(JavaThread *calling_thread, JavaThread* java_thread,
974 GrowableArray<jvmtiMonitorStackDepthInfo*> *owned_monitors_list) {
975 // Note:
976 // calling_thread is the thread that requested the list of monitors for java_thread.
977 // java_thread is the thread owning the monitors.
978 // current_thread is the thread executing this code, can be a non-JavaThread (e.g. VM Thread).
979 // And they all may be different threads.
980 jvmtiError err = JVMTI_ERROR_NONE;
981 Thread *current_thread = Thread::current();
982 assert(java_thread->is_handshake_safe_for(current_thread),
983 "call by myself or at handshake");
984
985 if (JvmtiEnvBase::is_cthread_with_continuation(java_thread)) {
986 // Carrier thread with a mounted continuation case.
987 // No contended monitor can be owned by carrier thread in this case.
988 return JVMTI_ERROR_NONE;
989 }
990 if (java_thread->has_last_Java_frame()) {
991 ResourceMark rm(current_thread);
992 HandleMark hm(current_thread);
993 RegisterMap reg_map(java_thread,
994 RegisterMap::UpdateMap::include,
995 RegisterMap::ProcessFrames::include,
996 RegisterMap::WalkContinuation::skip);
997
998 int depth = 0;
999 for (javaVFrame *jvf = get_cthread_last_java_vframe(java_thread, ®_map);
1000 jvf != nullptr; jvf = jvf->java_sender()) {
1001 if (MaxJavaStackTraceDepth == 0 || depth++ < MaxJavaStackTraceDepth) { // check for stack too deep
1002 // add locked objects for this frame into list
1003 err = get_locked_objects_in_frame(calling_thread, java_thread, jvf, owned_monitors_list, depth-1);
1004 if (err != JVMTI_ERROR_NONE) {
1005 return err;
1006 }
1007 }
1008 }
1009 }
1010
1011 // Get off stack monitors. (e.g. acquired via jni MonitorEnter).
1012 JvmtiMonitorClosure jmc(calling_thread, owned_monitors_list, this);
1013 ObjectSynchronizer::owned_monitors_iterate(&jmc, java_thread);
1014 err = jmc.error();
1015
1016 return err;
1017 }
1018
1019 jvmtiError
1020 JvmtiEnvBase::get_owned_monitors(JavaThread* calling_thread, JavaThread* carrier, javaVFrame* jvf,
1021 GrowableArray<jvmtiMonitorStackDepthInfo*> *owned_monitors_list, oop vthread) {
1022 jvmtiError err = JVMTI_ERROR_NONE;
1023 Thread *current_thread = Thread::current();
1024 assert(carrier == nullptr || carrier->is_handshake_safe_for(current_thread),
1025 "call by myself or at handshake");
1026
1027 int depth = 0;
1028 for ( ; jvf != nullptr; jvf = jvf->java_sender()) {
1029 if (MaxJavaStackTraceDepth == 0 || depth++ < MaxJavaStackTraceDepth) { // check for stack too deep
1030 // Add locked objects for this frame into list.
1031 err = get_locked_objects_in_frame(calling_thread, carrier, jvf, owned_monitors_list, depth - 1, vthread);
1032 if (err != JVMTI_ERROR_NONE) {
1033 return err;
1034 }
1035 }
1036 }
1037
1038 if (carrier == nullptr) {
1039 // vthread gets pinned if monitors are acquired via jni MonitorEnter
1040 // so nothing else to do for unmounted case.
1041 return err;
1042 }
1043
1044 // Get off stack monitors. (e.g. acquired via jni MonitorEnter).
1045 JvmtiMonitorClosure jmc(calling_thread, owned_monitors_list, this);
1046 ObjectSynchronizer::owned_monitors_iterate(&jmc, carrier);
1047 err = jmc.error();
1048
1049 return err;
1050 }
1051
1052 // Save JNI local handles for any objects that this frame owns.
1053 jvmtiError
1054 JvmtiEnvBase::get_locked_objects_in_frame(JavaThread* calling_thread, JavaThread* target,
1055 javaVFrame *jvf, GrowableArray<jvmtiMonitorStackDepthInfo*>* owned_monitors_list,
1056 jint stack_depth, oop vthread) {
1057 jvmtiError err = JVMTI_ERROR_NONE;
1058 Thread* current_thread = Thread::current();
1059 ResourceMark rm(current_thread);
1060 HandleMark hm(current_thread);
1061
1062 GrowableArray<MonitorInfo*>* mons = jvf->monitors();
1063 if (mons->is_empty()) {
1064 return err; // this javaVFrame holds no monitors
1065 }
1066
1067 oop wait_obj = nullptr;
1068 {
1069 // The ObjectMonitor* can't be async deflated since we are either
1070 // at a safepoint or the calling thread is operating on itself so
1071 // it cannot leave the underlying wait() call.
1072 // Save object of current wait() call (if any) for later comparison.
1073 if (target != nullptr) {
1074 ObjectMonitor *mon = target->current_waiting_monitor();
1075 if (mon != nullptr) wait_obj = mon->object();
1076 }
1077 }
1078 oop pending_obj = nullptr;
1079 {
1080 // The ObjectMonitor* can't be async deflated since we are either
1081 // at a safepoint or the calling thread is operating on itself so
1082 // it cannot leave the underlying enter() call.
1083 // Save object of current enter() call (if any) for later comparison.
1084 if (target != nullptr) {
1085 ObjectMonitor *mon = target->current_pending_monitor();
1086 if (mon != nullptr) pending_obj = mon->object();
1087 } else {
1088 assert(vthread != nullptr, "no vthread oop");
1089 oop oopCont = java_lang_VirtualThread::continuation(vthread);
1090 assert(oopCont != nullptr, "vthread with no continuation");
1091 stackChunkOop chunk = jdk_internal_vm_Continuation::tail(oopCont);
1092 assert(chunk != nullptr, "unmounted vthread should have a chunk");
1093 ObjectMonitor *mon = chunk->current_pending_monitor();
1094 if (mon != nullptr) pending_obj = mon->object();
1095 }
1096 }
1097
1098 for (int i = 0; i < mons->length(); i++) {
1099 MonitorInfo *mi = mons->at(i);
1100
1101 if (mi->owner_is_scalar_replaced()) continue;
1102
1103 oop obj = mi->owner();
1104 if (obj == nullptr) {
1105 // this monitor doesn't have an owning object so skip it
1106 continue;
1107 }
1108
1109 if (wait_obj == obj) {
1110 // the thread is waiting on this monitor so it isn't really owned
1111 continue;
1112 }
1113
1114 if (pending_obj == obj) {
1115 // the thread is pending on this monitor so it isn't really owned
1116 continue;
1117 }
1118
1119 if (owned_monitors_list->length() > 0) {
1120 // Our list has at least one object on it so we have to check
1121 // for recursive object locking
1122 bool found = false;
1123 for (int j = 0; j < owned_monitors_list->length(); j++) {
1124 jobject jobj = ((jvmtiMonitorStackDepthInfo*)owned_monitors_list->at(j))->monitor;
1125 oop check = JNIHandles::resolve(jobj);
1126 if (check == obj) {
1127 found = true; // we found the object
1128 break;
1129 }
1130 }
1131
1132 if (found) {
1133 // already have this object so don't include it
1134 continue;
1135 }
1136 }
1137
1138 // add the owning object to our list
1139 jvmtiMonitorStackDepthInfo *jmsdi;
1140 err = allocate(sizeof(jvmtiMonitorStackDepthInfo), (unsigned char **)&jmsdi);
1141 if (err != JVMTI_ERROR_NONE) {
1142 return err;
1143 }
1144 Handle hobj(Thread::current(), obj);
1145 jmsdi->monitor = jni_reference(calling_thread, hobj);
1146 jmsdi->stack_depth = stack_depth;
1147 owned_monitors_list->append(jmsdi);
1148 }
1149
1150 return err;
1151 }
1152
1153 jvmtiError
1154 JvmtiEnvBase::get_stack_trace(javaVFrame *jvf,
1155 jint start_depth, jint max_count,
1156 jvmtiFrameInfo* frame_buffer, jint* count_ptr) {
1157 Thread *current_thread = Thread::current();
1158 ResourceMark rm(current_thread);
1159 HandleMark hm(current_thread);
1160 int count = 0;
1161
1162 if (start_depth != 0) {
1163 if (start_depth > 0) {
1164 for (int j = 0; j < start_depth && jvf != nullptr; j++) {
1165 jvf = jvf->java_sender();
1166 }
1167 if (jvf == nullptr) {
1168 // start_depth is deeper than the stack depth.
1169 return JVMTI_ERROR_ILLEGAL_ARGUMENT;
1170 }
1171 } else { // start_depth < 0
1172 // We are referencing the starting depth based on the oldest
1173 // part of the stack.
1174 // Optimize to limit the number of times that java_sender() is called.
1175 javaVFrame *jvf_cursor = jvf;
1176 javaVFrame *jvf_prev = nullptr;
1177 javaVFrame *jvf_prev_prev = nullptr;
1178 int j = 0;
1179 while (jvf_cursor != nullptr) {
1180 jvf_prev_prev = jvf_prev;
1181 jvf_prev = jvf_cursor;
1182 for (j = 0; j > start_depth && jvf_cursor != nullptr; j--) {
1183 jvf_cursor = jvf_cursor->java_sender();
1184 }
1185 }
1186 if (j == start_depth) {
1187 // Previous pointer is exactly where we want to start.
1188 jvf = jvf_prev;
1189 } else {
1190 // We need to back up further to get to the right place.
1191 if (jvf_prev_prev == nullptr) {
1192 // The -start_depth is greater than the stack depth.
1193 return JVMTI_ERROR_ILLEGAL_ARGUMENT;
1194 }
1195 // j is now the number of frames on the stack starting with
1196 // jvf_prev, we start from jvf_prev_prev and move older on
1197 // the stack that many, and the result is -start_depth frames
1198 // remaining.
1199 jvf = jvf_prev_prev;
1200 for (; j < 0; j++) {
1201 jvf = jvf->java_sender();
1202 }
1203 }
1204 }
1205 }
1206 for (; count < max_count && jvf != nullptr; count++) {
1207 frame_buffer[count].method = jvf->method()->jmethod_id();
1208 frame_buffer[count].location = (jvf->method()->is_native() ? -1 : jvf->bci());
1209 jvf = jvf->java_sender();
1210 }
1211 *count_ptr = count;
1212 return JVMTI_ERROR_NONE;
1213 }
1214
1215 jvmtiError
1216 JvmtiEnvBase::get_stack_trace(JavaThread *java_thread,
1217 jint start_depth, jint max_count,
1218 jvmtiFrameInfo* frame_buffer, jint* count_ptr) {
1219 Thread *current_thread = Thread::current();
1220 assert(SafepointSynchronize::is_at_safepoint() ||
1221 java_thread->is_handshake_safe_for(current_thread),
1222 "call by myself / at safepoint / at handshake");
1223 int count = 0;
1224 jvmtiError err = JVMTI_ERROR_NONE;
1225
1226 if (java_thread->has_last_Java_frame()) {
1227 RegisterMap reg_map(java_thread,
1228 RegisterMap::UpdateMap::include,
1229 RegisterMap::ProcessFrames::skip,
1230 RegisterMap::WalkContinuation::skip);
1231 ResourceMark rm(current_thread);
1232 javaVFrame *jvf = get_cthread_last_java_vframe(java_thread, ®_map);
1233
1234 err = get_stack_trace(jvf, start_depth, max_count, frame_buffer, count_ptr);
1235 } else {
1236 *count_ptr = 0;
1237 if (start_depth != 0) {
1238 // no frames and there is a starting depth
1239 err = JVMTI_ERROR_ILLEGAL_ARGUMENT;
1240 }
1241 }
1242 return err;
1243 }
1244
1245 jint
1246 JvmtiEnvBase::get_frame_count(javaVFrame *jvf) {
1247 int count = 0;
1248
1249 while (jvf != nullptr) {
1250 jvf = jvf->java_sender();
1251 count++;
1252 }
1253 return count;
1254 }
1255
1256 jvmtiError
1257 JvmtiEnvBase::get_frame_count(JavaThread* jt, jint *count_ptr) {
1258 Thread *current_thread = Thread::current();
1259 assert(current_thread == jt ||
1260 SafepointSynchronize::is_at_safepoint() ||
1261 jt->is_handshake_safe_for(current_thread),
1262 "call by myself / at safepoint / at handshake");
1263
1264 if (!jt->has_last_Java_frame()) { // no Java frames
1265 *count_ptr = 0;
1266 } else {
1267 ResourceMark rm(current_thread);
1268 RegisterMap reg_map(jt,
1269 RegisterMap::UpdateMap::include,
1270 RegisterMap::ProcessFrames::include,
1271 RegisterMap::WalkContinuation::skip);
1272 javaVFrame *jvf = get_cthread_last_java_vframe(jt, ®_map);
1273
1274 *count_ptr = get_frame_count(jvf);
1275 }
1276 return JVMTI_ERROR_NONE;
1277 }
1278
1279 jvmtiError
1280 JvmtiEnvBase::get_frame_count(oop vthread_oop, jint *count_ptr) {
1281 Thread *current_thread = Thread::current();
1282 ResourceMark rm(current_thread);
1283 javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(vthread_oop);
1284
1285 *count_ptr = get_frame_count(jvf);
1286 return JVMTI_ERROR_NONE;
1287 }
1288
1289 jvmtiError
1290 JvmtiEnvBase::get_frame_location(javaVFrame* jvf, jint depth,
1291 jmethodID* method_ptr, jlocation* location_ptr) {
1292 int cur_depth = 0;
1293
1294 while (jvf != nullptr && cur_depth < depth) {
1295 jvf = jvf->java_sender();
1296 cur_depth++;
1297 }
1298 assert(depth >= cur_depth, "ran out of frames too soon");
1299 if (jvf == nullptr) {
1300 return JVMTI_ERROR_NO_MORE_FRAMES;
1301 }
1302 Method* method = jvf->method();
1303 if (method->is_native()) {
1304 *location_ptr = -1;
1305 } else {
1306 *location_ptr = jvf->bci();
1307 }
1308 *method_ptr = method->jmethod_id();
1309 return JVMTI_ERROR_NONE;
1310 }
1311
1312 jvmtiError
1313 JvmtiEnvBase::get_frame_location(JavaThread *java_thread, jint depth,
1314 jmethodID* method_ptr, jlocation* location_ptr) {
1315 Thread* current = Thread::current();
1316 assert(java_thread->is_handshake_safe_for(current),
1317 "call by myself or at handshake");
1318 if (!java_thread->has_last_Java_frame()) {
1319 return JVMTI_ERROR_NO_MORE_FRAMES;
1320 }
1321 ResourceMark rm(current);
1322 HandleMark hm(current);
1323 RegisterMap reg_map(java_thread,
1324 RegisterMap::UpdateMap::include,
1325 RegisterMap::ProcessFrames::skip,
1326 RegisterMap::WalkContinuation::include);
1327 javaVFrame* jvf = JvmtiEnvBase::get_cthread_last_java_vframe(java_thread, ®_map);
1328
1329 return get_frame_location(jvf, depth, method_ptr, location_ptr);
1330 }
1331
1332 jvmtiError
1333 JvmtiEnvBase::get_frame_location(oop vthread_oop, jint depth,
1334 jmethodID* method_ptr, jlocation* location_ptr) {
1335 Thread* current = Thread::current();
1336 ResourceMark rm(current);
1337 HandleMark hm(current);
1338 javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(vthread_oop);
1339
1340 return get_frame_location(jvf, depth, method_ptr, location_ptr);
1341 }
1342
1343 jvmtiError
1344 JvmtiEnvBase::set_frame_pop(JvmtiThreadState* state, javaVFrame* jvf, jint depth) {
1345 for (int d = 0; jvf != nullptr && d < depth; d++) {
1346 jvf = jvf->java_sender();
1347 }
1348 if (jvf == nullptr) {
1349 return JVMTI_ERROR_NO_MORE_FRAMES;
1350 }
1351 if (jvf->method()->is_native()) {
1352 return JVMTI_ERROR_OPAQUE_FRAME;
1353 }
1354 assert(jvf->frame_pointer() != nullptr, "frame pointer mustn't be null");
1355 int frame_number = (int)get_frame_count(jvf);
1356 state->env_thread_state((JvmtiEnvBase*)this)->set_frame_pop(frame_number);
1357 return JVMTI_ERROR_NONE;
1358 }
1359
1360 bool
1361 JvmtiEnvBase::is_cthread_with_mounted_vthread(JavaThread* jt) {
1362 oop thread_oop = jt->threadObj();
1363 assert(thread_oop != nullptr, "sanity check");
1364 oop mounted_vt = jt->jvmti_vthread();
1365
1366 return mounted_vt != nullptr && mounted_vt != thread_oop;
1367 }
1368
1369 bool
1370 JvmtiEnvBase::is_cthread_with_continuation(JavaThread* jt) {
1371 const ContinuationEntry* cont_entry = nullptr;
1372 if (jt->has_last_Java_frame()) {
1373 cont_entry = jt->vthread_continuation();
1374 }
1375 return cont_entry != nullptr && is_cthread_with_mounted_vthread(jt);
1376 }
1377
1378 // Check if VirtualThread or BoundVirtualThread is suspended.
1379 bool
1380 JvmtiEnvBase::is_vthread_suspended(oop vt_oop, JavaThread* jt) {
1381 bool suspended = false;
1382 if (java_lang_VirtualThread::is_instance(vt_oop)) {
1383 suspended = JvmtiVTSuspender::is_vthread_suspended(vt_oop);
1384 }
1385 if (vt_oop->is_a(vmClasses::BoundVirtualThread_klass())) {
1386 suspended = jt->is_suspended();
1387 }
1388 return suspended;
1389 }
1390
1391 // If (thread == null) then return current thread object.
1392 // Otherwise return JNIHandles::resolve_external_guard(thread).
1393 oop
1394 JvmtiEnvBase::current_thread_obj_or_resolve_external_guard(jthread thread) {
1395 oop thread_obj = JNIHandles::resolve_external_guard(thread);
1396 if (thread == nullptr) {
1397 thread_obj = get_vthread_or_thread_oop(JavaThread::current());
1398 }
1399 return thread_obj;
1400 }
1401
1402 jvmtiError
1403 JvmtiEnvBase::get_threadOop_and_JavaThread(ThreadsList* t_list, jthread thread, JavaThread* cur_thread,
1404 JavaThread** jt_pp, oop* thread_oop_p) {
1405 JavaThread* java_thread = nullptr;
1406 oop thread_oop = nullptr;
1407
1408 if (thread == nullptr) {
1409 if (cur_thread == nullptr) { // cur_thread can be null when called from a VM_op
1410 return JVMTI_ERROR_INVALID_THREAD;
1411 }
1412 java_thread = cur_thread;
1413 thread_oop = get_vthread_or_thread_oop(java_thread);
1414 if (thread_oop == nullptr || !thread_oop->is_a(vmClasses::Thread_klass())) {
1415 return JVMTI_ERROR_INVALID_THREAD;
1416 }
1417 } else {
1418 jvmtiError err = JvmtiExport::cv_external_thread_to_JavaThread(t_list, thread, &java_thread, &thread_oop);
1419 if (err != JVMTI_ERROR_NONE) {
1420 // We got an error code so we don't have a JavaThread*, but only return
1421 // an error from here if we didn't get a valid thread_oop. In a vthread case
1422 // the cv_external_thread_to_JavaThread is expected to correctly set the
1423 // thread_oop and return JVMTI_ERROR_INVALID_THREAD which we ignore here.
1424 if (thread_oop == nullptr || err != JVMTI_ERROR_INVALID_THREAD) {
1425 *thread_oop_p = thread_oop;
1426 return err;
1427 }
1428 }
1429 if (java_thread == nullptr && java_lang_VirtualThread::is_instance(thread_oop)) {
1430 java_thread = get_JavaThread_or_null(thread_oop);
1431 }
1432 }
1433 *jt_pp = java_thread;
1434 *thread_oop_p = thread_oop;
1435 if (java_lang_VirtualThread::is_instance(thread_oop) &&
1436 !JvmtiEnvBase::is_vthread_alive(thread_oop)) {
1437 return JVMTI_ERROR_THREAD_NOT_ALIVE;
1438 }
1439 return JVMTI_ERROR_NONE;
1440 }
1441
1442 // Check for JVMTI_ERROR_NOT_SUSPENDED and JVMTI_ERROR_OPAQUE_FRAME errors.
1443 // Used in PopFrame and ForceEarlyReturn implementations.
1444 jvmtiError
1445 JvmtiEnvBase::check_non_suspended_or_opaque_frame(JavaThread* jt, oop thr_obj, bool self) {
1446 bool is_virtual = thr_obj != nullptr && thr_obj->is_a(vmClasses::BaseVirtualThread_klass());
1447
1448 if (is_virtual) {
1449 if (!is_JavaThread_current(jt, thr_obj)) {
1450 if (!is_vthread_suspended(thr_obj, jt)) {
1451 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1452 }
1453 if (jt == nullptr) { // unmounted virtual thread
1454 return JVMTI_ERROR_OPAQUE_FRAME;
1455 }
1456 }
1457 } else { // platform thread
1458 if (!self && !jt->is_suspended() &&
1459 !jt->is_carrier_thread_suspended()) {
1460 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1461 }
1462 }
1463 return JVMTI_ERROR_NONE;
1464 }
1465
1466 jvmtiError
1467 JvmtiEnvBase::get_object_monitor_usage(JavaThread* calling_thread, jobject object, jvmtiMonitorUsage* info_ptr) {
1468 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
1469 Thread* current_thread = VMThread::vm_thread();
1470 assert(current_thread == Thread::current(), "must be");
1471
1472 HandleMark hm(current_thread);
1473 Handle hobj;
1474
1475 // Check arguments
1476 {
1477 oop mirror = JNIHandles::resolve_external_guard(object);
1478 NULL_CHECK(mirror, JVMTI_ERROR_INVALID_OBJECT);
1479 NULL_CHECK(info_ptr, JVMTI_ERROR_NULL_POINTER);
1480
1481 hobj = Handle(current_thread, mirror);
1482 }
1483
1484 ThreadsListHandle tlh(current_thread);
1485 JavaThread *owning_thread = nullptr;
1486 ObjectMonitor *mon = nullptr;
1487 jvmtiMonitorUsage ret = {
1488 nullptr, 0, 0, nullptr, 0, nullptr
1489 };
1490
1491 uint32_t debug_bits = 0;
1492 // first derive the object's owner and entry_count (if any)
1493 owning_thread = ObjectSynchronizer::get_lock_owner(tlh.list(), hobj);
1494 if (owning_thread != nullptr) {
1495 oop thread_oop = get_vthread_or_thread_oop(owning_thread);
1496 bool is_virtual = thread_oop->is_a(vmClasses::BaseVirtualThread_klass());
1497 if (is_virtual) {
1498 thread_oop = nullptr;
1499 }
1500 Handle th(current_thread, thread_oop);
1501 ret.owner = (jthread)jni_reference(calling_thread, th);
1502
1503 // The recursions field of a monitor does not reflect recursions
1504 // as lightweight locks before inflating the monitor are not included.
1505 // We have to count the number of recursive monitor entries the hard way.
1506 // We pass a handle to survive any GCs along the way.
1507 ret.entry_count = is_virtual ? 0 : count_locked_objects(owning_thread, hobj);
1508 }
1509 // implied else: entry_count == 0
1510
1511 jint nWant = 0, nWait = 0;
1512 markWord mark = hobj->mark();
1513 ResourceMark rm(current_thread);
1514 GrowableArray<JavaThread*>* wantList = nullptr;
1515
1516 if (mark.has_monitor()) {
1517 mon = mark.monitor();
1518 assert(mon != nullptr, "must have monitor");
1519 // this object has a heavyweight monitor
1520 nWant = mon->contentions(); // # of threads contending for monitor entry, but not re-entry
1521 nWait = mon->waiters(); // # of threads waiting for notification,
1522 // or to re-enter monitor, in Object.wait()
1523
1524 // Get the actual set of threads trying to enter, or re-enter, the monitor.
1525 wantList = Threads::get_pending_threads(tlh.list(), nWant + nWait, (address)mon);
1526 nWant = wantList->length();
1527 } else {
1528 // this object has a lightweight monitor
1529 }
1530
1531 jint skipped = 0;
1532 if (mon != nullptr) {
1533 // Robustness: the actual waiting list can be smaller.
1534 // The nWait count we got from the mon->waiters() may include the re-entering
1535 // the monitor threads after being notified. Here we are correcting the actual
1536 // number of the waiting threads by excluding those re-entering the monitor.
1537 nWait = 0;
1538 for (ObjectWaiter* waiter = mon->first_waiter();
1539 waiter != nullptr && (nWait == 0 || waiter != mon->first_waiter());
1540 waiter = mon->next_waiter(waiter)) {
1541 JavaThread *w = mon->thread_of_waiter(waiter);
1542 if (w == nullptr) {
1543 skipped++;
1544 } else {
1545 oop thread_oop = get_vthread_or_thread_oop(w);
1546 if (thread_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1547 skipped++;
1548 }
1549 }
1550 nWait++;
1551 }
1552 }
1553 ret.waiter_count = nWant;
1554 ret.notify_waiter_count = nWait - skipped;
1555
1556 // Allocate memory for heavyweight and lightweight monitor.
1557 jvmtiError err;
1558 err = allocate(ret.waiter_count * sizeof(jthread *), (unsigned char**)&ret.waiters);
1559 if (err != JVMTI_ERROR_NONE) {
1560 return err;
1561 }
1562 err = allocate(ret.notify_waiter_count * sizeof(jthread *),
1563 (unsigned char**)&ret.notify_waiters);
1564 if (err != JVMTI_ERROR_NONE) {
1565 deallocate((unsigned char*)ret.waiters);
1566 return err;
1567 }
1568
1569 // now derive the rest of the fields
1570 if (mon != nullptr) {
1571 // this object has a heavyweight monitor
1572
1573 // null out memory for robustness
1574 if (ret.waiters != nullptr) {
1575 memset(ret.waiters, 0, ret.waiter_count * sizeof(jthread *));
1576 }
1577 if (ret.notify_waiters != nullptr) {
1578 memset(ret.notify_waiters, 0, ret.notify_waiter_count * sizeof(jthread *));
1579 }
1580
1581 if (ret.waiter_count > 0) { // we have contending threads waiting to enter/re-enter the monitor
1582 // identify threads waiting to enter and re-enter the monitor
1583 // get_pending_threads returns only java thread so we do not need to
1584 // check for non java threads.
1585 for (int i = 0; i < nWant; i++) {
1586 JavaThread *pending_thread = wantList->at(i);
1587 Handle th(current_thread, get_vthread_or_thread_oop(pending_thread));
1588 ret.waiters[i] = (jthread)jni_reference(calling_thread, th);
1589 }
1590 }
1591 if (ret.notify_waiter_count > 0) { // we have threads waiting to be notified in Object.wait()
1592 ObjectWaiter *waiter = mon->first_waiter();
1593 jint skipped = 0;
1594 for (int i = 0; i < nWait; i++) {
1595 JavaThread *w = mon->thread_of_waiter(waiter);
1596 bool is_virtual;
1597 if (w == nullptr) {
1598 is_virtual = true;
1599 } else {
1600 oop thread_oop = get_vthread_or_thread_oop(w);
1601 is_virtual = thread_oop->is_a(vmClasses::BaseVirtualThread_klass());
1602 }
1603 if (is_virtual) {
1604 skipped++;
1605 } else {
1606 // If the thread was found on the ObjectWaiter list, then
1607 // it has not been notified.
1608 Handle th(current_thread, w->threadObj());
1609 ret.notify_waiters[i - skipped] = (jthread)jni_reference(calling_thread, th);
1610 }
1611 waiter = mon->next_waiter(waiter);
1612 }
1613 }
1614 } else {
1615 // this object has a lightweight monitor and we have nothing more
1616 // to do here because the defaults are just fine.
1617 }
1618
1619 // we don't update return parameter unless everything worked
1620 *info_ptr = ret;
1621
1622 return JVMTI_ERROR_NONE;
1623 }
1624
1625 jvmtiError
1626 JvmtiEnvBase::check_thread_list(jint count, const jthread* list) {
1627 if (list == nullptr && count != 0) {
1628 return JVMTI_ERROR_NULL_POINTER;
1629 }
1630 for (int i = 0; i < count; i++) {
1631 jthread thread = list[i];
1632 oop thread_oop = JNIHandles::resolve_external_guard(thread);
1633 if (thread_oop == nullptr || !thread_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1634 return JVMTI_ERROR_INVALID_THREAD;
1635 }
1636 }
1637 return JVMTI_ERROR_NONE;
1638 }
1639
1640 bool
1641 JvmtiEnvBase::is_in_thread_list(jint count, const jthread* list, oop jt_oop) {
1642 for (int idx = 0; idx < count; idx++) {
1643 jthread thread = list[idx];
1644 oop thread_oop = JNIHandles::resolve_external_guard(thread);
1645 if (thread_oop == jt_oop) {
1646 return true;
1647 }
1648 }
1649 return false;
1650 }
1651
1652 class VM_SetNotifyJvmtiEventsMode : public VM_Operation {
1653 private:
1654 bool _enable;
1655
1656 static void correct_jvmti_thread_state(JavaThread* jt) {
1657 oop ct_oop = jt->threadObj();
1658 oop vt_oop = jt->vthread();
1659 JvmtiThreadState* jt_state = jt->jvmti_thread_state();
1660 JvmtiThreadState* ct_state = java_lang_Thread::jvmti_thread_state(jt->threadObj());
1661 JvmtiThreadState* vt_state = vt_oop != nullptr ? java_lang_Thread::jvmti_thread_state(vt_oop) : nullptr;
1662 bool virt = vt_oop != nullptr && java_lang_VirtualThread::is_instance(vt_oop);
1663
1664 // Correct jt->jvmti_thread_state() and jt->jvmti_vthread().
1665 // It was not maintained while notifyJvmti was disabled.
1666 if (virt) {
1667 jt->set_jvmti_thread_state(nullptr); // reset jt->jvmti_thread_state()
1668 jt->set_jvmti_vthread(vt_oop); // restore jt->jvmti_vthread()
1669 } else {
1670 jt->set_jvmti_thread_state(ct_state); // restore jt->jvmti_thread_state()
1671 jt->set_jvmti_vthread(ct_oop); // restore jt->jvmti_vthread()
1672 }
1673 }
1674
1675 // This function is called only if _enable == true.
1676 // Iterates over all JavaThread's, restores jt->jvmti_thread_state() and
1677 // jt->jvmti_vthread() for VTMS transition protocol.
1678 void correct_jvmti_thread_states() {
1679 for (JavaThread* jt : ThreadsListHandle()) {
1680 if (jt->is_in_VTMS_transition()) {
1681 jt->set_VTMS_transition_mark(true);
1682 continue; // no need in JvmtiThreadState correction below if in transition
1683 }
1684 correct_jvmti_thread_state(jt);
1685 }
1686 }
1687
1688 public:
1689 VMOp_Type type() const { return VMOp_SetNotifyJvmtiEventsMode; }
1690 bool allow_nested_vm_operations() const { return false; }
1691 VM_SetNotifyJvmtiEventsMode(bool enable) : _enable(enable) {
1692 }
1693
1694 void doit() {
1695 if (_enable) {
1696 correct_jvmti_thread_states();
1697 }
1698 JvmtiVTMSTransitionDisabler::set_VTMS_notify_jvmti_events(_enable);
1699 }
1700 };
1701
1702 // This function is to support agents loaded into running VM.
1703 // Must be called in thread-in-native mode.
1704 bool
1705 JvmtiEnvBase::enable_virtual_threads_notify_jvmti() {
1706 if (!Continuations::enabled()) {
1707 return false;
1708 }
1709 if (JvmtiVTMSTransitionDisabler::VTMS_notify_jvmti_events()) {
1710 return false; // already enabled
1711 }
1712 VM_SetNotifyJvmtiEventsMode op(true);
1713 VMThread::execute(&op);
1714 return true;
1715 }
1716
1717 // This function is used in WhiteBox, only needed to test the function above.
1718 // It is unsafe to use this function when virtual threads are executed.
1719 // Must be called in thread-in-native mode.
1720 bool
1721 JvmtiEnvBase::disable_virtual_threads_notify_jvmti() {
1722 if (!Continuations::enabled()) {
1723 return false;
1724 }
1725 if (!JvmtiVTMSTransitionDisabler::VTMS_notify_jvmti_events()) {
1726 return false; // already disabled
1727 }
1728 JvmtiVTMSTransitionDisabler disabler(true); // ensure there are no other disablers
1729 VM_SetNotifyJvmtiEventsMode op(false);
1730 VMThread::execute(&op);
1731 return true;
1732 }
1733
1734 // java_thread - protected by ThreadsListHandle
1735 jvmtiError
1736 JvmtiEnvBase::suspend_thread(oop thread_oop, JavaThread* java_thread, bool single_suspend,
1737 int* need_safepoint_p) {
1738 JavaThread* current = JavaThread::current();
1739 HandleMark hm(current);
1740 Handle thread_h(current, thread_oop);
1741 bool is_virtual = java_lang_VirtualThread::is_instance(thread_h());
1742
1743 if (is_virtual) {
1744 if (single_suspend) {
1745 if (JvmtiVTSuspender::is_vthread_suspended(thread_h())) {
1746 return JVMTI_ERROR_THREAD_SUSPENDED;
1747 }
1748 JvmtiVTSuspender::register_vthread_suspend(thread_h());
1749 // Check if virtual thread is mounted and there is a java_thread.
1750 // A non-null java_thread is always passed in the !single_suspend case.
1751 oop carrier_thread = java_lang_VirtualThread::carrier_thread(thread_h());
1752 java_thread = carrier_thread == nullptr ? nullptr : java_lang_Thread::thread(carrier_thread);
1753 }
1754 // The java_thread can be still blocked in VTMS transition after a previous JVMTI resume call.
1755 // There is no need to suspend the java_thread in this case. After vthread unblocking,
1756 // it will check for ext_suspend request and suspend itself if necessary.
1757 if (java_thread == nullptr || java_thread->is_suspended()) {
1758 // We are done if the virtual thread is unmounted or
1759 // the java_thread is externally suspended.
1760 return JVMTI_ERROR_NONE;
1761 }
1762 // The virtual thread is mounted: suspend the java_thread.
1763 }
1764 // Don't allow hidden thread suspend request.
1765 if (java_thread->is_hidden_from_external_view()) {
1766 return JVMTI_ERROR_NONE;
1767 }
1768 bool is_thread_carrying = is_thread_carrying_vthread(java_thread, thread_h());
1769
1770 // A case of non-virtual thread.
1771 if (!is_virtual) {
1772 // Thread.suspend() is used in some tests. It sets jt->is_suspended() only.
1773 if (java_thread->is_carrier_thread_suspended() ||
1774 (!is_thread_carrying && java_thread->is_suspended())) {
1775 return JVMTI_ERROR_THREAD_SUSPENDED;
1776 }
1777 java_thread->set_carrier_thread_suspended();
1778 }
1779 assert(!java_thread->is_in_VTMS_transition(), "sanity check");
1780
1781 assert(!single_suspend || (!is_virtual && java_thread->is_carrier_thread_suspended()) ||
1782 (is_virtual && JvmtiVTSuspender::is_vthread_suspended(thread_h())),
1783 "sanity check");
1784
1785 // An attempt to handshake-suspend a thread carrying a virtual thread will result in
1786 // suspension of mounted virtual thread. So, we just mark it as suspended
1787 // and it will be actually suspended at virtual thread unmount transition.
1788 if (!is_thread_carrying) {
1789 assert(thread_h() != nullptr, "sanity check");
1790 assert(single_suspend || thread_h()->is_a(vmClasses::BaseVirtualThread_klass()),
1791 "SuspendAllVirtualThreads should never suspend non-virtual threads");
1792 // Case of mounted virtual or attached carrier thread.
1793 if (!JvmtiSuspendControl::suspend(java_thread)) {
1794 // Thread is already suspended or in process of exiting.
1795 if (java_thread->is_exiting()) {
1796 // The thread was in the process of exiting.
1797 return JVMTI_ERROR_THREAD_NOT_ALIVE;
1798 }
1799 return JVMTI_ERROR_THREAD_SUSPENDED;
1800 }
1801 }
1802 return JVMTI_ERROR_NONE;
1803 }
1804
1805 // java_thread - protected by ThreadsListHandle
1806 jvmtiError
1807 JvmtiEnvBase::resume_thread(oop thread_oop, JavaThread* java_thread, bool single_resume) {
1808 JavaThread* current = JavaThread::current();
1809 HandleMark hm(current);
1810 Handle thread_h(current, thread_oop);
1811 bool is_virtual = java_lang_VirtualThread::is_instance(thread_h());
1812
1813 if (is_virtual) {
1814 if (single_resume) {
1815 if (!JvmtiVTSuspender::is_vthread_suspended(thread_h())) {
1816 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1817 }
1818 JvmtiVTSuspender::register_vthread_resume(thread_h());
1819 // Check if virtual thread is mounted and there is a java_thread.
1820 // A non-null java_thread is always passed in the !single_resume case.
1821 oop carrier_thread = java_lang_VirtualThread::carrier_thread(thread_h());
1822 java_thread = carrier_thread == nullptr ? nullptr : java_lang_Thread::thread(carrier_thread);
1823 }
1824 // The java_thread can be still blocked in VTMS transition after a previous JVMTI suspend call.
1825 // There is no need to resume the java_thread in this case. After vthread unblocking,
1826 // it will check for is_vthread_suspended request and remain resumed if necessary.
1827 if (java_thread == nullptr || !java_thread->is_suspended()) {
1828 // We are done if the virtual thread is unmounted or
1829 // the java_thread is not externally suspended.
1830 return JVMTI_ERROR_NONE;
1831 }
1832 // The virtual thread is mounted and java_thread is supended: resume the java_thread.
1833 }
1834 // Don't allow hidden thread resume request.
1835 if (java_thread->is_hidden_from_external_view()) {
1836 return JVMTI_ERROR_NONE;
1837 }
1838 bool is_thread_carrying = is_thread_carrying_vthread(java_thread, thread_h());
1839
1840 // A case of a non-virtual thread.
1841 if (!is_virtual) {
1842 if (!java_thread->is_carrier_thread_suspended() &&
1843 (is_thread_carrying || !java_thread->is_suspended())) {
1844 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1845 }
1846 java_thread->clear_carrier_thread_suspended();
1847 }
1848 assert(!java_thread->is_in_VTMS_transition(), "sanity check");
1849
1850 if (!is_thread_carrying) {
1851 assert(thread_h() != nullptr, "sanity check");
1852 assert(single_resume || thread_h()->is_a(vmClasses::BaseVirtualThread_klass()),
1853 "ResumeAllVirtualThreads should never resume non-virtual threads");
1854 if (java_thread->is_suspended()) {
1855 if (!JvmtiSuspendControl::resume(java_thread)) {
1856 return JVMTI_ERROR_THREAD_NOT_SUSPENDED;
1857 }
1858 }
1859 }
1860 return JVMTI_ERROR_NONE;
1861 }
1862
1863 ResourceTracker::ResourceTracker(JvmtiEnv* env) {
1864 _env = env;
1865 _allocations = new (mtServiceability) GrowableArray<unsigned char*>(20, mtServiceability);
1866 _failed = false;
1867 }
1868 ResourceTracker::~ResourceTracker() {
1869 if (_failed) {
1870 for (int i=0; i<_allocations->length(); i++) {
1871 _env->deallocate(_allocations->at(i));
1872 }
1873 }
1874 delete _allocations;
1875 }
1876
1877 jvmtiError ResourceTracker::allocate(jlong size, unsigned char** mem_ptr) {
1878 unsigned char *ptr;
1879 jvmtiError err = _env->allocate(size, &ptr);
1880 if (err == JVMTI_ERROR_NONE) {
1881 _allocations->append(ptr);
1882 *mem_ptr = ptr;
1883 } else {
1884 *mem_ptr = nullptr;
1885 _failed = true;
1886 }
1887 return err;
1888 }
1889
1890 unsigned char* ResourceTracker::allocate(jlong size) {
1891 unsigned char* ptr;
1892 allocate(size, &ptr);
1893 return ptr;
1894 }
1895
1896 char* ResourceTracker::strdup(const char* str) {
1897 char *dup_str = (char*)allocate(strlen(str)+1);
1898 if (dup_str != nullptr) {
1899 strcpy(dup_str, str);
1900 }
1901 return dup_str;
1902 }
1903
1904 struct StackInfoNode {
1905 struct StackInfoNode *next;
1906 jvmtiStackInfo info;
1907 };
1908
1909 // Create a jvmtiStackInfo inside a linked list node and create a
1910 // buffer for the frame information, both allocated as resource objects.
1911 // Fill in both the jvmtiStackInfo and the jvmtiFrameInfo.
1912 // Note that either or both of thr and thread_oop
1913 // may be null if the thread is new or has exited.
1914 void
1915 MultipleStackTracesCollector::fill_frames(jthread jt, JavaThread *thr, oop thread_oop) {
1916 #ifdef ASSERT
1917 Thread *current_thread = Thread::current();
1918 assert(SafepointSynchronize::is_at_safepoint() ||
1919 thr == nullptr ||
1920 thr->is_handshake_safe_for(current_thread),
1921 "unmounted virtual thread / call by myself / at safepoint / at handshake");
1922 #endif
1923
1924 jint state = 0;
1925 struct StackInfoNode *node = NEW_RESOURCE_OBJ(struct StackInfoNode);
1926 jvmtiStackInfo *infop = &(node->info);
1927
1928 node->next = head();
1929 set_head(node);
1930 infop->frame_count = 0;
1931 infop->frame_buffer = nullptr;
1932 infop->thread = jt;
1933
1934 if (java_lang_VirtualThread::is_instance(thread_oop)) {
1935 state = JvmtiEnvBase::get_vthread_state(thread_oop, thr);
1936
1937 if ((state & JVMTI_THREAD_STATE_ALIVE) != 0) {
1938 javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(thread_oop);
1939 infop->frame_buffer = NEW_RESOURCE_ARRAY(jvmtiFrameInfo, max_frame_count());
1940 _result = env()->get_stack_trace(jvf, 0, max_frame_count(),
1941 infop->frame_buffer, &(infop->frame_count));
1942 }
1943 } else {
1944 state = JvmtiEnvBase::get_thread_state(thread_oop, thr);
1945 if (thr != nullptr && (state & JVMTI_THREAD_STATE_ALIVE) != 0) {
1946 infop->frame_buffer = NEW_RESOURCE_ARRAY(jvmtiFrameInfo, max_frame_count());
1947 _result = env()->get_stack_trace(thr, 0, max_frame_count(),
1948 infop->frame_buffer, &(infop->frame_count));
1949 }
1950 }
1951 _frame_count_total += infop->frame_count;
1952 infop->state = state;
1953 }
1954
1955 // Based on the stack information in the linked list, allocate memory
1956 // block to return and fill it from the info in the linked list.
1957 void
1958 MultipleStackTracesCollector::allocate_and_fill_stacks(jint thread_count) {
1959 // do I need to worry about alignment issues?
1960 jlong alloc_size = thread_count * sizeof(jvmtiStackInfo)
1961 + _frame_count_total * sizeof(jvmtiFrameInfo);
1962 env()->allocate(alloc_size, (unsigned char **)&_stack_info);
1963
1964 // pointers to move through the newly allocated space as it is filled in
1965 jvmtiStackInfo *si = _stack_info + thread_count; // bottom of stack info
1966 jvmtiFrameInfo *fi = (jvmtiFrameInfo *)si; // is the top of frame info
1967
1968 // copy information in resource area into allocated buffer
1969 // insert stack info backwards since linked list is backwards
1970 // insert frame info forwards
1971 // walk the StackInfoNodes
1972 for (struct StackInfoNode *sin = head(); sin != nullptr; sin = sin->next) {
1973 jint frame_count = sin->info.frame_count;
1974 size_t frames_size = frame_count * sizeof(jvmtiFrameInfo);
1975 --si;
1976 memcpy(si, &(sin->info), sizeof(jvmtiStackInfo));
1977 if (frames_size == 0) {
1978 si->frame_buffer = nullptr;
1979 } else {
1980 memcpy(fi, sin->info.frame_buffer, frames_size);
1981 si->frame_buffer = fi; // point to the new allocated copy of the frames
1982 fi += frame_count;
1983 }
1984 }
1985 assert(si == _stack_info, "the last copied stack info must be the first record");
1986 assert((unsigned char *)fi == ((unsigned char *)_stack_info) + alloc_size,
1987 "the last copied frame info must be the last record");
1988 }
1989
1990 // AdapterClosure is to make use of JvmtiUnitedHandshakeClosure objects from
1991 // Handshake::execute() which is unaware of the do_vthread() member functions.
1992 class AdapterClosure : public HandshakeClosure {
1993 JvmtiUnitedHandshakeClosure* _hs_cl;
1994 Handle _target_h;
1995
1996 public:
1997 AdapterClosure(JvmtiUnitedHandshakeClosure* hs_cl, Handle target_h)
1998 : HandshakeClosure(hs_cl->name()), _hs_cl(hs_cl), _target_h(target_h) {}
1999
2000 virtual void do_thread(Thread* target) {
2001 if (java_lang_VirtualThread::is_instance(_target_h())) {
2002 _hs_cl->do_vthread(_target_h); // virtual thread
2003 } else {
2004 _hs_cl->do_thread(target); // platform thread
2005 }
2006 }
2007 };
2008
2009 // Supports platform and virtual threads.
2010 // JvmtiVTMSTransitionDisabler is always set by this function.
2011 void
2012 JvmtiHandshake::execute(JvmtiUnitedHandshakeClosure* hs_cl, jthread target) {
2013 JavaThread* current = JavaThread::current();
2014 HandleMark hm(current);
2015
2016 JvmtiVTMSTransitionDisabler disabler(target);
2017 ThreadsListHandle tlh(current);
2018 JavaThread* java_thread = nullptr;
2019 oop thread_obj = nullptr;
2020
2021 jvmtiError err = JvmtiEnvBase::get_threadOop_and_JavaThread(tlh.list(), target, current, &java_thread, &thread_obj);
2022 if (err != JVMTI_ERROR_NONE) {
2023 hs_cl->set_result(err);
2024 return;
2025 }
2026 Handle target_h(current, thread_obj);
2027 execute(hs_cl, &tlh, java_thread, target_h);
2028 }
2029
2030 // Supports platform and virtual threads.
2031 // A virtual thread is always identified by the target_h oop handle.
2032 // The target_jt is always nullptr for an unmounted virtual thread.
2033 // JvmtiVTMSTransitionDisabler has to be set before call to this function.
2034 void
2035 JvmtiHandshake::execute(JvmtiUnitedHandshakeClosure* hs_cl, ThreadsListHandle* tlh,
2036 JavaThread* target_jt, Handle target_h) {
2037 JavaThread* current = JavaThread::current();
2038 bool is_virtual = java_lang_VirtualThread::is_instance(target_h());
2039 bool self = target_jt == current;
2040
2041 assert(!Continuations::enabled() || self || !is_virtual || current->is_VTMS_transition_disabler(), "sanity check");
2042
2043 hs_cl->set_target_jt(target_jt); // can be needed in the virtual thread case
2044 hs_cl->set_is_virtual(is_virtual); // can be needed in the virtual thread case
2045 hs_cl->set_self(self); // needed when suspend is required for non-current target thread
2046
2047 if (is_virtual) { // virtual thread
2048 if (!JvmtiEnvBase::is_vthread_alive(target_h())) {
2049 return;
2050 }
2051 if (target_jt == nullptr) { // unmounted virtual thread
2052 hs_cl->do_vthread(target_h); // execute handshake closure callback on current thread directly
2053 }
2054 }
2055 if (target_jt != nullptr) { // mounted virtual or platform thread
2056 AdapterClosure acl(hs_cl, target_h);
2057 if (self) { // target platform thread is current
2058 acl.do_thread(target_jt); // execute handshake closure callback on current thread directly
2059 } else {
2060 Handshake::execute(&acl, tlh, target_jt); // delegate to Handshake implementation
2061 }
2062 }
2063 }
2064
2065 void
2066 VM_GetThreadListStackTraces::doit() {
2067 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
2068
2069 ResourceMark rm;
2070 ThreadsListHandle tlh;
2071 for (int i = 0; i < _thread_count; ++i) {
2072 jthread jt = _thread_list[i];
2073 JavaThread* java_thread = nullptr;
2074 oop thread_oop = nullptr;
2075 jvmtiError err = JvmtiEnvBase::get_threadOop_and_JavaThread(tlh.list(), jt, nullptr, &java_thread, &thread_oop);
2076
2077 if (err != JVMTI_ERROR_NONE) {
2078 // We got an error code so we don't have a JavaThread *, but
2079 // only return an error from here if we didn't get a valid
2080 // thread_oop.
2081 // In the virtual thread case the get_threadOop_and_JavaThread is expected to correctly set
2082 // the thread_oop and return JVMTI_ERROR_THREAD_NOT_ALIVE which we ignore here.
2083 // The corresponding thread state will be recorded in the jvmtiStackInfo.state.
2084 if (thread_oop == nullptr) {
2085 _collector.set_result(err);
2086 return;
2087 }
2088 // We have a valid thread_oop.
2089 }
2090 _collector.fill_frames(jt, java_thread, thread_oop);
2091 }
2092 _collector.allocate_and_fill_stacks(_thread_count);
2093 }
2094
2095 void
2096 GetSingleStackTraceClosure::doit() {
2097 JavaThread *jt = _target_jt;
2098 oop thread_oop = JNIHandles::resolve_external_guard(_jthread);
2099
2100 if ((jt == nullptr || !jt->is_exiting()) && thread_oop != nullptr) {
2101 ResourceMark rm;
2102 _collector.fill_frames(_jthread, jt, thread_oop);
2103 _collector.allocate_and_fill_stacks(1);
2104 set_result(_collector.result());
2105 }
2106 }
2107
2108 void
2109 GetSingleStackTraceClosure::do_thread(Thread *target) {
2110 assert(_target_jt == JavaThread::cast(target), "sanity check");
2111 doit();
2112 }
2113
2114 void
2115 GetSingleStackTraceClosure::do_vthread(Handle target_h) {
2116 // Use jvmti_vthread() instead of vthread() as target could have temporarily changed
2117 // identity to carrier thread (see VirtualThread.switchToCarrierThread).
2118 assert(_target_jt == nullptr || _target_jt->jvmti_vthread() == target_h(), "sanity check");
2119 doit();
2120 }
2121
2122 void
2123 VM_GetAllStackTraces::doit() {
2124 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
2125
2126 ResourceMark rm;
2127 _final_thread_count = 0;
2128 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) {
2129 oop thread_oop = jt->threadObj();
2130 if (thread_oop != nullptr &&
2131 !jt->is_exiting() &&
2132 java_lang_Thread::is_alive(thread_oop) &&
2133 !jt->is_hidden_from_external_view() &&
2134 !thread_oop->is_a(vmClasses::BoundVirtualThread_klass())) {
2135 ++_final_thread_count;
2136 // Handle block of the calling thread is used to create local refs.
2137 _collector.fill_frames((jthread)JNIHandles::make_local(_calling_thread, thread_oop),
2138 jt, thread_oop);
2139 }
2140 }
2141 _collector.allocate_and_fill_stacks(_final_thread_count);
2142 }
2143
2144 // Verifies that the top frame is a java frame in an expected state.
2145 // Deoptimizes frame if needed.
2146 // Checks that the frame method signature matches the return type (tos).
2147 // HandleMark must be defined in the caller only.
2148 // It is to keep a ret_ob_h handle alive after return to the caller.
2149 jvmtiError
2150 JvmtiEnvBase::check_top_frame(Thread* current_thread, JavaThread* java_thread,
2151 jvalue value, TosState tos, Handle* ret_ob_h) {
2152 ResourceMark rm(current_thread);
2153
2154 javaVFrame* jvf = jvf_for_thread_and_depth(java_thread, 0);
2155 NULL_CHECK(jvf, JVMTI_ERROR_NO_MORE_FRAMES);
2156
2157 if (jvf->method()->is_native()) {
2158 return JVMTI_ERROR_OPAQUE_FRAME;
2159 }
2160
2161 // If the frame is a compiled one, need to deoptimize it.
2162 if (jvf->is_compiled_frame()) {
2163 if (!jvf->fr().can_be_deoptimized()) {
2164 return JVMTI_ERROR_OPAQUE_FRAME;
2165 }
2166 Deoptimization::deoptimize_frame(java_thread, jvf->fr().id());
2167 }
2168
2169 // Get information about method return type
2170 Symbol* signature = jvf->method()->signature();
2171
2172 ResultTypeFinder rtf(signature);
2173 TosState fr_tos = as_TosState(rtf.type());
2174 if (fr_tos != tos) {
2175 if (tos != itos || (fr_tos != btos && fr_tos != ztos && fr_tos != ctos && fr_tos != stos)) {
2176 return JVMTI_ERROR_TYPE_MISMATCH;
2177 }
2178 }
2179
2180 // Check that the jobject class matches the return type signature.
2181 jobject jobj = value.l;
2182 if (tos == atos && jobj != nullptr) { // null reference is allowed
2183 Handle ob_h(current_thread, JNIHandles::resolve_external_guard(jobj));
2184 NULL_CHECK(ob_h, JVMTI_ERROR_INVALID_OBJECT);
2185 Klass* ob_k = ob_h()->klass();
2186 NULL_CHECK(ob_k, JVMTI_ERROR_INVALID_OBJECT);
2187
2188 // Method return type signature.
2189 char* ty_sign = 1 + strchr(signature->as_C_string(), JVM_SIGNATURE_ENDFUNC);
2190
2191 if (!VM_GetOrSetLocal::is_assignable(ty_sign, ob_k, current_thread)) {
2192 return JVMTI_ERROR_TYPE_MISMATCH;
2193 }
2194 *ret_ob_h = ob_h;
2195 }
2196 return JVMTI_ERROR_NONE;
2197 } /* end check_top_frame */
2198
2199
2200 // ForceEarlyReturn<type> follows the PopFrame approach in many aspects.
2201 // Main difference is on the last stage in the interpreter.
2202 // The PopFrame stops method execution to continue execution
2203 // from the same method call instruction.
2204 // The ForceEarlyReturn forces return from method so the execution
2205 // continues at the bytecode following the method call.
2206
2207 // thread - NOT protected by ThreadsListHandle and NOT pre-checked
2208
2209 jvmtiError
2210 JvmtiEnvBase::force_early_return(jthread thread, jvalue value, TosState tos) {
2211 JavaThread* current_thread = JavaThread::current();
2212 HandleMark hm(current_thread);
2213
2214 JvmtiVTMSTransitionDisabler disabler(thread);
2215 ThreadsListHandle tlh(current_thread);
2216
2217 JavaThread* java_thread = nullptr;
2218 oop thread_obj = nullptr;
2219 jvmtiError err = get_threadOop_and_JavaThread(tlh.list(), thread, current_thread, &java_thread, &thread_obj);
2220
2221 if (err != JVMTI_ERROR_NONE) {
2222 return err;
2223 }
2224 Handle thread_handle(current_thread, thread_obj);
2225 bool self = java_thread == current_thread;
2226
2227 err = check_non_suspended_or_opaque_frame(java_thread, thread_obj, self);
2228 if (err != JVMTI_ERROR_NONE) {
2229 return err;
2230 }
2231
2232 // retrieve or create the state
2233 JvmtiThreadState* state = JvmtiThreadState::state_for(java_thread);
2234 if (state == nullptr) {
2235 return JVMTI_ERROR_THREAD_NOT_ALIVE;
2236 }
2237
2238 // Eagerly reallocate scalar replaced objects.
2239 EscapeBarrier eb(true, current_thread, java_thread);
2240 if (!eb.deoptimize_objects(0)) {
2241 // Reallocation of scalar replaced objects failed -> return with error
2242 return JVMTI_ERROR_OUT_OF_MEMORY;
2243 }
2244
2245 MutexLocker mu(JvmtiThreadState_lock);
2246 SetForceEarlyReturn op(state, value, tos);
2247 JvmtiHandshake::execute(&op, &tlh, java_thread, thread_handle);
2248 return op.result();
2249 }
2250
2251 void
2252 SetForceEarlyReturn::doit(Thread *target) {
2253 JavaThread* java_thread = JavaThread::cast(target);
2254 Thread* current_thread = Thread::current();
2255 HandleMark hm(current_thread);
2256
2257 if (java_thread->is_exiting()) {
2258 return; /* JVMTI_ERROR_THREAD_NOT_ALIVE (default) */
2259 }
2260
2261 // Check to see if a ForceEarlyReturn was already in progress
2262 if (_state->is_earlyret_pending()) {
2263 // Probably possible for JVMTI clients to trigger this, but the
2264 // JPDA backend shouldn't allow this to happen
2265 _result = JVMTI_ERROR_INTERNAL;
2266 return;
2267 }
2268 {
2269 // The same as for PopFrame. Workaround bug:
2270 // 4812902: popFrame hangs if the method is waiting at a synchronize
2271 // Catch this condition and return an error to avoid hanging.
2272 // Now JVMTI spec allows an implementation to bail out with an opaque
2273 // frame error.
2274 OSThread* osThread = java_thread->osthread();
2275 if (osThread->get_state() == MONITOR_WAIT) {
2276 _result = JVMTI_ERROR_OPAQUE_FRAME;
2277 return;
2278 }
2279 }
2280
2281 Handle ret_ob_h;
2282 _result = JvmtiEnvBase::check_top_frame(current_thread, java_thread, _value, _tos, &ret_ob_h);
2283 if (_result != JVMTI_ERROR_NONE) {
2284 return;
2285 }
2286 assert(_tos != atos || _value.l == nullptr || ret_ob_h() != nullptr,
2287 "return object oop must not be null if jobject is not null");
2288
2289 // Update the thread state to reflect that the top frame must be
2290 // forced to return.
2291 // The current frame will be returned later when the suspended
2292 // thread is resumed and right before returning from VM to Java.
2293 // (see call_VM_base() in assembler_<cpu>.cpp).
2294
2295 _state->set_earlyret_pending();
2296 _state->set_earlyret_oop(ret_ob_h());
2297 _state->set_earlyret_value(_value, _tos);
2298
2299 // Set pending step flag for this early return.
2300 // It is cleared when next step event is posted.
2301 _state->set_pending_step_for_earlyret();
2302 }
2303
2304 void
2305 JvmtiMonitorClosure::do_monitor(ObjectMonitor* mon) {
2306 if ( _error != JVMTI_ERROR_NONE) {
2307 // Error occurred in previous iteration so no need to add
2308 // to the list.
2309 return;
2310 }
2311 // Filter out on stack monitors collected during stack walk.
2312 oop obj = mon->object();
2313
2314 if (obj == nullptr) {
2315 // This can happen if JNI code drops all references to the
2316 // owning object.
2317 return;
2318 }
2319
2320 bool found = false;
2321 for (int j = 0; j < _owned_monitors_list->length(); j++) {
2322 jobject jobj = ((jvmtiMonitorStackDepthInfo*)_owned_monitors_list->at(j))->monitor;
2323 oop check = JNIHandles::resolve(jobj);
2324 if (check == obj) {
2325 // On stack monitor already collected during the stack walk.
2326 found = true;
2327 break;
2328 }
2329 }
2330 if (found == false) {
2331 // This is off stack monitor (e.g. acquired via jni MonitorEnter).
2332 jvmtiError err;
2333 jvmtiMonitorStackDepthInfo *jmsdi;
2334 err = _env->allocate(sizeof(jvmtiMonitorStackDepthInfo), (unsigned char **)&jmsdi);
2335 if (err != JVMTI_ERROR_NONE) {
2336 _error = err;
2337 return;
2338 }
2339 Handle hobj(Thread::current(), obj);
2340 jmsdi->monitor = _env->jni_reference(_calling_thread, hobj);
2341 // stack depth is unknown for this monitor.
2342 jmsdi->stack_depth = -1;
2343 _owned_monitors_list->append(jmsdi);
2344 }
2345 }
2346
2347 GrowableArray<OopHandle>* JvmtiModuleClosure::_tbl = nullptr;
2348
2349 void JvmtiModuleClosure::do_module(ModuleEntry* entry) {
2350 assert_locked_or_safepoint(Module_lock);
2351 OopHandle module = entry->module_handle();
2352 guarantee(module.resolve() != nullptr, "module object is null");
2353 _tbl->push(module);
2354 }
2355
2356 jvmtiError
2357 JvmtiModuleClosure::get_all_modules(JvmtiEnv* env, jint* module_count_ptr, jobject** modules_ptr) {
2358 ResourceMark rm;
2359 MutexLocker mcld(ClassLoaderDataGraph_lock);
2360 MutexLocker ml(Module_lock);
2361
2362 _tbl = new GrowableArray<OopHandle>(77);
2363 if (_tbl == nullptr) {
2364 return JVMTI_ERROR_OUT_OF_MEMORY;
2365 }
2366
2367 // Iterate over all the modules loaded to the system.
2368 ClassLoaderDataGraph::modules_do_keepalive(&do_module);
2369
2370 jint len = _tbl->length();
2371 guarantee(len > 0, "at least one module must be present");
2372
2373 jobject* array = (jobject*)env->jvmtiMalloc((jlong)(len * sizeof(jobject)));
2374 if (array == nullptr) {
2375 return JVMTI_ERROR_OUT_OF_MEMORY;
2376 }
2377 for (jint idx = 0; idx < len; idx++) {
2378 array[idx] = JNIHandles::make_local(_tbl->at(idx).resolve());
2379 }
2380 _tbl = nullptr;
2381 *modules_ptr = array;
2382 *module_count_ptr = len;
2383 return JVMTI_ERROR_NONE;
2384 }
2385
2386 void
2387 UpdateForPopTopFrameClosure::doit(Thread *target) {
2388 Thread* current_thread = Thread::current();
2389 HandleMark hm(current_thread);
2390 JavaThread* java_thread = JavaThread::cast(target);
2391
2392 if (java_thread->is_exiting()) {
2393 return; /* JVMTI_ERROR_THREAD_NOT_ALIVE (default) */
2394 }
2395 assert(java_thread == _state->get_thread(), "Must be");
2396
2397 // Check to see if a PopFrame was already in progress
2398 if (java_thread->popframe_condition() != JavaThread::popframe_inactive) {
2399 // Probably possible for JVMTI clients to trigger this, but the
2400 // JPDA backend shouldn't allow this to happen
2401 _result = JVMTI_ERROR_INTERNAL;
2402 return;
2403 }
2404
2405 // Was workaround bug
2406 // 4812902: popFrame hangs if the method is waiting at a synchronize
2407 // Catch this condition and return an error to avoid hanging.
2408 // Now JVMTI spec allows an implementation to bail out with an opaque frame error.
2409 OSThread* osThread = java_thread->osthread();
2410 if (osThread->get_state() == MONITOR_WAIT) {
2411 _result = JVMTI_ERROR_OPAQUE_FRAME;
2412 return;
2413 }
2414
2415 ResourceMark rm(current_thread);
2416 // Check if there is more than one Java frame in this thread, that the top two frames
2417 // are Java (not native) frames, and that there is no intervening VM frame
2418 int frame_count = 0;
2419 bool is_interpreted[2];
2420 intptr_t *frame_sp[2];
2421 // The 2-nd arg of constructor is needed to stop iterating at java entry frame.
2422 for (vframeStream vfs(java_thread, true, false /* process_frames */); !vfs.at_end(); vfs.next()) {
2423 methodHandle mh(current_thread, vfs.method());
2424 if (mh->is_native()) {
2425 _result = JVMTI_ERROR_OPAQUE_FRAME;
2426 return;
2427 }
2428 is_interpreted[frame_count] = vfs.is_interpreted_frame();
2429 frame_sp[frame_count] = vfs.frame_id();
2430 if (++frame_count > 1) break;
2431 }
2432 if (frame_count < 2) {
2433 // We haven't found two adjacent non-native Java frames on the top.
2434 // There can be two situations here:
2435 // 1. There are no more java frames
2436 // 2. Two top java frames are separated by non-java native frames
2437 if (JvmtiEnvBase::jvf_for_thread_and_depth(java_thread, 1) == nullptr) {
2438 _result = JVMTI_ERROR_NO_MORE_FRAMES;
2439 return;
2440 } else {
2441 // Intervening non-java native or VM frames separate java frames.
2442 // Current implementation does not support this. See bug #5031735.
2443 // In theory it is possible to pop frames in such cases.
2444 _result = JVMTI_ERROR_OPAQUE_FRAME;
2445 return;
2446 }
2447 }
2448
2449 // If any of the top 2 frames is a compiled one, need to deoptimize it
2450 for (int i = 0; i < 2; i++) {
2451 if (!is_interpreted[i]) {
2452 Deoptimization::deoptimize_frame(java_thread, frame_sp[i]);
2453 }
2454 }
2455
2456 // Update the thread state to reflect that the top frame is popped
2457 // so that cur_stack_depth is maintained properly and all frameIDs
2458 // are invalidated.
2459 // The current frame will be popped later when the suspended thread
2460 // is resumed and right before returning from VM to Java.
2461 // (see call_VM_base() in assembler_<cpu>.cpp).
2462
2463 // It's fine to update the thread state here because no JVMTI events
2464 // shall be posted for this PopFrame.
2465
2466 _state->update_for_pop_top_frame();
2467 java_thread->set_popframe_condition(JavaThread::popframe_pending_bit);
2468 // Set pending step flag for this popframe and it is cleared when next
2469 // step event is posted.
2470 _state->set_pending_step_for_popframe();
2471 _result = JVMTI_ERROR_NONE;
2472 }
2473
2474 void
2475 SetFramePopClosure::do_thread(Thread *target) {
2476 Thread* current = Thread::current();
2477 ResourceMark rm(current); // vframes are resource allocated
2478 JavaThread* java_thread = JavaThread::cast(target);
2479
2480 if (java_thread->is_exiting()) {
2481 return; // JVMTI_ERROR_THREAD_NOT_ALIVE (default)
2482 }
2483
2484 if (!_self && !java_thread->is_suspended()) {
2485 _result = JVMTI_ERROR_THREAD_NOT_SUSPENDED;
2486 return;
2487 }
2488 if (!java_thread->has_last_Java_frame()) {
2489 _result = JVMTI_ERROR_NO_MORE_FRAMES;
2490 return;
2491 }
2492 assert(_state->get_thread_or_saved() == java_thread, "Must be");
2493
2494 RegisterMap reg_map(java_thread,
2495 RegisterMap::UpdateMap::include,
2496 RegisterMap::ProcessFrames::skip,
2497 RegisterMap::WalkContinuation::include);
2498 javaVFrame* jvf = JvmtiEnvBase::get_cthread_last_java_vframe(java_thread, ®_map);
2499 _result = ((JvmtiEnvBase*)_env)->set_frame_pop(_state, jvf, _depth);
2500 }
2501
2502 void
2503 SetFramePopClosure::do_vthread(Handle target_h) {
2504 Thread* current = Thread::current();
2505 ResourceMark rm(current); // vframes are resource allocated
2506
2507 if (!_self && !JvmtiVTSuspender::is_vthread_suspended(target_h())) {
2508 _result = JVMTI_ERROR_THREAD_NOT_SUSPENDED;
2509 return;
2510 }
2511 javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(target_h());
2512 _result = ((JvmtiEnvBase*)_env)->set_frame_pop(_state, jvf, _depth);
2513 }
2514
2515 void
2516 GetOwnedMonitorInfoClosure::do_thread(Thread *target) {
2517 JavaThread *jt = JavaThread::cast(target);
2518 if (!jt->is_exiting() && (jt->threadObj() != nullptr)) {
2519 _result = ((JvmtiEnvBase *)_env)->get_owned_monitors(_calling_thread,
2520 jt,
2521 _owned_monitors_list);
2522 }
2523 }
2524
2525 void
2526 GetOwnedMonitorInfoClosure::do_vthread(Handle target_h) {
2527 Thread* current = Thread::current();
2528 ResourceMark rm(current); // vframes are resource allocated
2529 HandleMark hm(current);
2530
2531 javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(target_h());
2532
2533 if (_target_jt == nullptr || (!_target_jt->is_exiting() && _target_jt->threadObj() != nullptr)) {
2534 _result = ((JvmtiEnvBase *)_env)->get_owned_monitors(_calling_thread,
2535 _target_jt,
2536 jvf,
2537 _owned_monitors_list,
2538 target_h());
2539 }
2540 }
2541
2542 void
2543 GetCurrentContendedMonitorClosure::do_thread(Thread *target) {
2544 JavaThread *jt = JavaThread::cast(target);
2545 if (!jt->is_exiting() && (jt->threadObj() != nullptr)) {
2546 _result = ((JvmtiEnvBase *)_env)->get_current_contended_monitor(_calling_thread,
2547 jt,
2548 _owned_monitor_ptr,
2549 _is_virtual);
2550 }
2551 }
2552
2553 void
2554 GetCurrentContendedMonitorClosure::do_vthread(Handle target_h) {
2555 if (_target_jt == nullptr) {
2556 oop cont = java_lang_VirtualThread::continuation(target_h());
2557 assert(cont != nullptr, "vthread with no continuation");
2558 stackChunkOop chunk = jdk_internal_vm_Continuation::tail(cont);
2559 assert(chunk != nullptr, "unmounted vthread should have a chunk");
2560 if (chunk->current_pending_monitor() != nullptr) {
2561 *_owned_monitor_ptr = JNIHandles::make_local(_calling_thread, chunk->current_pending_monitor()->object());
2562 }
2563 _result = JVMTI_ERROR_NONE; // target virtual thread is unmounted
2564 return;
2565 }
2566 // mounted virtual thread case
2567 do_thread(_target_jt);
2568 }
2569
2570 void
2571 GetStackTraceClosure::do_thread(Thread *target) {
2572 Thread* current = Thread::current();
2573 ResourceMark rm(current);
2574
2575 JavaThread *jt = JavaThread::cast(target);
2576 if (!jt->is_exiting() && jt->threadObj() != nullptr) {
2577 _result = ((JvmtiEnvBase *)_env)->get_stack_trace(jt,
2578 _start_depth, _max_count,
2579 _frame_buffer, _count_ptr);
2580 }
2581 }
2582
2583 void
2584 GetStackTraceClosure::do_vthread(Handle target_h) {
2585 Thread* current = Thread::current();
2586 ResourceMark rm(current);
2587
2588 javaVFrame *jvf = JvmtiEnvBase::get_vthread_jvf(target_h());
2589 _result = ((JvmtiEnvBase *)_env)->get_stack_trace(jvf,
2590 _start_depth, _max_count,
2591 _frame_buffer, _count_ptr);
2592 }
2593
2594 #ifdef ASSERT
2595 void
2596 PrintStackTraceClosure::do_thread_impl(Thread *target) {
2597 JavaThread *java_thread = JavaThread::cast(target);
2598 Thread *current_thread = Thread::current();
2599
2600 ResourceMark rm (current_thread);
2601 const char* tname = JvmtiTrace::safe_get_thread_name(java_thread);
2602 oop t_oop = java_thread->jvmti_vthread();
2603 t_oop = t_oop == nullptr ? java_thread->threadObj() : t_oop;
2604 bool is_vt_suspended = java_lang_VirtualThread::is_instance(t_oop) && JvmtiVTSuspender::is_vthread_suspended(t_oop);
2605
2606 log_error(jvmti)("%s(%s) exiting: %d is_susp: %d is_thread_susp: %d is_vthread_susp: %d "
2607 "is_VTMS_transition_disabler: %d, is_in_VTMS_transition = %d\n",
2608 tname, java_thread->name(), java_thread->is_exiting(),
2609 java_thread->is_suspended(), java_thread->is_carrier_thread_suspended(), is_vt_suspended,
2610 java_thread->is_VTMS_transition_disabler(), java_thread->is_in_VTMS_transition());
2611
2612 if (java_thread->has_last_Java_frame()) {
2613 RegisterMap reg_map(java_thread,
2614 RegisterMap::UpdateMap::include,
2615 RegisterMap::ProcessFrames::include,
2616 RegisterMap::WalkContinuation::skip);
2617 ResourceMark rm(current_thread);
2618 HandleMark hm(current_thread);
2619 javaVFrame *jvf = java_thread->last_java_vframe(®_map);
2620 while (jvf != nullptr) {
2621 log_error(jvmti)(" %s:%d",
2622 jvf->method()->external_name(),
2623 jvf->method()->line_number_from_bci(jvf->bci()));
2624 jvf = jvf->java_sender();
2625 }
2626 }
2627 log_error(jvmti)("\n");
2628 }
2629
2630 void
2631 PrintStackTraceClosure::do_thread(Thread *target) {
2632 JavaThread *java_thread = JavaThread::cast(target);
2633 Thread *current_thread = Thread::current();
2634
2635 assert(SafepointSynchronize::is_at_safepoint() ||
2636 java_thread->is_handshake_safe_for(current_thread),
2637 "call by myself / at safepoint / at handshake");
2638
2639 PrintStackTraceClosure::do_thread_impl(target);
2640 }
2641 #endif
2642
2643 void
2644 GetFrameCountClosure::do_thread(Thread *target) {
2645 JavaThread* jt = JavaThread::cast(target);
2646 assert(target == jt, "just checking");
2647
2648 if (!jt->is_exiting() && jt->threadObj() != nullptr) {
2649 _result = ((JvmtiEnvBase*)_env)->get_frame_count(jt, _count_ptr);
2650 }
2651 }
2652
2653 void
2654 GetFrameCountClosure::do_vthread(Handle target_h) {
2655 _result = ((JvmtiEnvBase*)_env)->get_frame_count(target_h(), _count_ptr);
2656 }
2657
2658 void
2659 GetFrameLocationClosure::do_thread(Thread *target) {
2660 JavaThread *jt = JavaThread::cast(target);
2661 assert(target == jt, "just checking");
2662
2663 if (!jt->is_exiting() && jt->threadObj() != nullptr) {
2664 _result = ((JvmtiEnvBase*)_env)->get_frame_location(jt, _depth,
2665 _method_ptr, _location_ptr);
2666 }
2667 }
2668
2669 void
2670 GetFrameLocationClosure::do_vthread(Handle target_h) {
2671 _result = ((JvmtiEnvBase*)_env)->get_frame_location(target_h(), _depth,
2672 _method_ptr, _location_ptr);
2673 }