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