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