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