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