1 /*
   2  * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/symbolTable.hpp"
  27 #include "classfile/vmSymbols.hpp"
  28 #include "code/codeCache.hpp"
  29 #include "compiler/compileBroker.hpp"
  30 #include "gc/shared/collectedHeap.hpp"
  31 #include "gc/shared/isGCActiveMark.hpp"
  32 #include "logging/log.hpp"
  33 #include "logging/logStream.hpp"
  34 #include "logging/logConfiguration.hpp"
  35 #include "memory/heapInspection.hpp"
  36 #include "memory/resourceArea.hpp"
  37 #include "memory/universe.hpp"
  38 #include "oops/symbol.hpp"
  39 #include "runtime/arguments.hpp"
  40 #include "runtime/deoptimization.hpp"
  41 #include "runtime/frame.inline.hpp"
  42 #include "runtime/interfaceSupport.inline.hpp"
  43 #include "runtime/sweeper.hpp"
  44 #include "runtime/synchronizer.hpp"
  45 #include "runtime/thread.inline.hpp"
  46 #include "runtime/threadSMR.inline.hpp"
  47 #include "runtime/vmOperations.hpp"
  48 #include "services/threadService.hpp"
  49 
  50 #define VM_OP_NAME_INITIALIZE(name) #name,
  51 
  52 const char* VM_Operation::_names[VM_Operation::VMOp_Terminating] = \
  53   { VM_OPS_DO(VM_OP_NAME_INITIALIZE) };
  54 
  55 void VM_Operation::set_calling_thread(Thread* thread, ThreadPriority priority) {
  56   _calling_thread = thread;
  57   assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
  58   _priority = priority;
  59 }
  60 
  61 
  62 void VM_Operation::evaluate() {
  63   ResourceMark rm;
  64   LogTarget(Debug, vmoperation) lt;
  65   if (lt.is_enabled()) {
  66     LogStream ls(lt);
  67     ls.print("begin ");
  68     print_on_error(&ls);
  69     ls.cr();
  70   }
  71   doit();
  72   if (lt.is_enabled()) {
  73     LogStream ls(lt);
  74     ls.print("end ");
  75     print_on_error(&ls);
  76     ls.cr();
  77   }
  78 }
  79 
  80 const char* VM_Operation::mode_to_string(Mode mode) {
  81   switch(mode) {
  82     case _safepoint      : return "safepoint";
  83     case _no_safepoint   : return "no safepoint";
  84     case _concurrent     : return "concurrent";
  85     case _async_safepoint: return "async safepoint";
  86     default              : return "unknown";
  87   }
  88 }
  89 // Called by fatal error handler.
  90 void VM_Operation::print_on_error(outputStream* st) const {
  91   st->print("VM_Operation (" PTR_FORMAT "): ", p2i(this));
  92   st->print("%s", name());
  93 
  94   const char* mode = mode_to_string(evaluation_mode());
  95   st->print(", mode: %s", mode);
  96 
  97   if (calling_thread()) {
  98     st->print(", requested by thread " PTR_FORMAT, p2i(calling_thread()));
  99   }
 100 }
 101 
 102 void VM_ThreadStop::doit() {
 103   assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
 104   ThreadsListHandle tlh;
 105   JavaThread* target = java_lang_Thread::thread(target_thread());
 106   // Note that this now allows multiple ThreadDeath exceptions to be
 107   // thrown at a thread.
 108   if (target != NULL && (!EnableThreadSMRExtraValidityChecks || tlh.includes(target))) {
 109     // The target thread has run and has not exited yet.
 110     target->send_thread_stop(throwable());
 111   }
 112 }
 113 
 114 void VM_ClearICs::doit() {
 115   if (_preserve_static_stubs) {
 116     CodeCache::cleanup_inline_caches();
 117   } else {
 118     CodeCache::clear_inline_caches();
 119   }
 120 }
 121 
 122 void VM_Deoptimize::doit() {
 123   // We do not want any GCs to happen while we are in the middle of this VM operation
 124   ResourceMark rm;
 125   DeoptimizationMarker dm;
 126 
 127   // Deoptimize all activations depending on marked nmethods
 128   Deoptimization::deoptimize_dependents();
 129 
 130   // Make the dependent methods not entrant
 131   CodeCache::make_marked_nmethods_not_entrant();
 132 }
 133 
 134 void VM_MarkActiveNMethods::doit() {
 135   NMethodSweeper::mark_active_nmethods();
 136 }
 137 
 138 VM_DeoptimizeFrame::VM_DeoptimizeFrame(JavaThread* thread, intptr_t* id, int reason) {
 139   _thread = thread;
 140   _id     = id;
 141   _reason = reason;
 142 }
 143 
 144 
 145 void VM_DeoptimizeFrame::doit() {
 146   assert(_reason > Deoptimization::Reason_none && _reason < Deoptimization::Reason_LIMIT, "invalid deopt reason");
 147   Deoptimization::deoptimize_frame_internal(_thread, _id, (Deoptimization::DeoptReason)_reason);
 148 }
 149 
 150 
 151 #ifndef PRODUCT
 152 
 153 void VM_DeoptimizeAll::doit() {
 154   DeoptimizationMarker dm;
 155   JavaThreadIteratorWithHandle jtiwh;
 156   // deoptimize all java threads in the system
 157   if (DeoptimizeALot) {
 158     for (; JavaThread *thread = jtiwh.next(); ) {
 159       if (thread->has_last_Java_frame()) {
 160         thread->deoptimize();
 161       }
 162     }
 163   } else if (DeoptimizeRandom) {
 164 
 165     // Deoptimize some selected threads and frames
 166     int tnum = os::random() & 0x3;
 167     int fnum =  os::random() & 0x3;
 168     int tcount = 0;
 169     for (; JavaThread *thread = jtiwh.next(); ) {
 170       if (thread->has_last_Java_frame()) {
 171         if (tcount++ == tnum)  {
 172         tcount = 0;
 173           int fcount = 0;
 174           // Deoptimize some selected frames.
 175           // Biased llocking wants a updated register map
 176           for(StackFrameStream fst(thread, UseBiasedLocking); !fst.is_done(); fst.next()) {
 177             if (fst.current()->can_be_deoptimized()) {
 178               if (fcount++ == fnum) {
 179                 fcount = 0;
 180                 Deoptimization::deoptimize(thread, *fst.current(), fst.register_map());
 181               }
 182             }
 183           }
 184         }
 185       }
 186     }
 187   }
 188 }
 189 
 190 
 191 void VM_ZombieAll::doit() {
 192   JavaThread *thread = (JavaThread *)calling_thread();
 193   assert(thread->is_Java_thread(), "must be a Java thread");
 194   thread->make_zombies();
 195 }
 196 
 197 #endif // !PRODUCT
 198 
 199 void VM_Verify::doit() {
 200   Universe::heap()->prepare_for_verify();
 201   Universe::verify();
 202 }
 203 
 204 bool VM_PrintThreads::doit_prologue() {
 205   // Get Heap_lock if concurrent locks will be dumped
 206   if (_print_concurrent_locks) {
 207     Heap_lock->lock();
 208   }
 209   return true;
 210 }
 211 
 212 void VM_PrintThreads::doit() {
 213   Threads::print_on(_out, true, false, _print_concurrent_locks, _print_extended_info);
 214 }
 215 
 216 void VM_PrintThreads::doit_epilogue() {
 217   if (_print_concurrent_locks) {
 218     // Release Heap_lock
 219     Heap_lock->unlock();
 220   }
 221 }
 222 
 223 void VM_PrintJNI::doit() {
 224   JNIHandles::print_on(_out);
 225 }
 226 
 227 void VM_PrintMetadata::doit() {
 228   MetaspaceUtils::print_report(_out, _scale, _flags);
 229 }
 230 
 231 VM_FindDeadlocks::~VM_FindDeadlocks() {
 232   if (_deadlocks != NULL) {
 233     DeadlockCycle* cycle = _deadlocks;
 234     while (cycle != NULL) {
 235       DeadlockCycle* d = cycle;
 236       cycle = cycle->next();
 237       delete d;
 238     }
 239   }
 240 }
 241 
 242 void VM_FindDeadlocks::doit() {
 243   // Update the hazard ptr in the originating thread to the current
 244   // list of threads. This VM operation needs the current list of
 245   // threads for proper deadlock detection and those are the
 246   // JavaThreads we need to be protected when we return info to the
 247   // originating thread.
 248   _setter.set();
 249 
 250   _deadlocks = ThreadService::find_deadlocks_at_safepoint(_setter.list(), _concurrent_locks);
 251   if (_out != NULL) {
 252     int num_deadlocks = 0;
 253     for (DeadlockCycle* cycle = _deadlocks; cycle != NULL; cycle = cycle->next()) {
 254       num_deadlocks++;
 255       cycle->print_on_with(_setter.list(), _out);
 256     }
 257 
 258     if (num_deadlocks == 1) {
 259       _out->print_cr("\nFound 1 deadlock.\n");
 260       _out->flush();
 261     } else if (num_deadlocks > 1) {
 262       _out->print_cr("\nFound %d deadlocks.\n", num_deadlocks);
 263       _out->flush();
 264     }
 265   }
 266 }
 267 
 268 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
 269                              int max_depth,
 270                              bool with_locked_monitors,
 271                              bool with_locked_synchronizers) {
 272   _result = result;
 273   _num_threads = 0; // 0 indicates all threads
 274   _threads = NULL;
 275   _result = result;
 276   _max_depth = max_depth;
 277   _with_locked_monitors = with_locked_monitors;
 278   _with_locked_synchronizers = with_locked_synchronizers;
 279 }
 280 
 281 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
 282                              GrowableArray<instanceHandle>* threads,
 283                              int num_threads,
 284                              int max_depth,
 285                              bool with_locked_monitors,
 286                              bool with_locked_synchronizers) {
 287   _result = result;
 288   _num_threads = num_threads;
 289   _threads = threads;
 290   _result = result;
 291   _max_depth = max_depth;
 292   _with_locked_monitors = with_locked_monitors;
 293   _with_locked_synchronizers = with_locked_synchronizers;
 294 }
 295 
 296 bool VM_ThreadDump::doit_prologue() {
 297   if (_with_locked_synchronizers) {
 298     // Acquire Heap_lock to dump concurrent locks
 299     Heap_lock->lock();
 300   }
 301 
 302   return true;
 303 }
 304 
 305 void VM_ThreadDump::doit_epilogue() {
 306   if (_with_locked_synchronizers) {
 307     // Release Heap_lock
 308     Heap_lock->unlock();
 309   }
 310 }
 311 
 312 void VM_ThreadDump::doit() {
 313   ResourceMark rm;
 314 
 315   // Set the hazard ptr in the originating thread to protect the
 316   // current list of threads. This VM operation needs the current list
 317   // of threads for a proper dump and those are the JavaThreads we need
 318   // to be protected when we return info to the originating thread.
 319   _result->set_t_list();
 320 
 321   ConcurrentLocksDump concurrent_locks(true);
 322   if (_with_locked_synchronizers) {
 323     concurrent_locks.dump_at_safepoint();
 324   }
 325 
 326   if (_num_threads == 0) {
 327     // Snapshot all live threads
 328 
 329     for (uint i = 0; i < _result->t_list()->length(); i++) {
 330       JavaThread* jt = _result->t_list()->thread_at(i);
 331       if (jt->is_exiting() ||
 332           jt->is_hidden_from_external_view())  {
 333         // skip terminating threads and hidden threads
 334         continue;
 335       }
 336       ThreadConcurrentLocks* tcl = NULL;
 337       if (_with_locked_synchronizers) {
 338         tcl = concurrent_locks.thread_concurrent_locks(jt);
 339       }
 340       snapshot_thread(jt, tcl);
 341     }
 342   } else {
 343     // Snapshot threads in the given _threads array
 344     // A dummy snapshot is created if a thread doesn't exist
 345 
 346     for (int i = 0; i < _num_threads; i++) {
 347       instanceHandle th = _threads->at(i);
 348       if (th() == NULL) {
 349         // skip if the thread doesn't exist
 350         // Add a dummy snapshot
 351         _result->add_thread_snapshot();
 352         continue;
 353       }
 354 
 355       // Dump thread stack only if the thread is alive and not exiting
 356       // and not VM internal thread.
 357       JavaThread* jt = java_lang_Thread::thread(th());
 358       if (jt != NULL && !_result->t_list()->includes(jt)) {
 359         // _threads[i] doesn't refer to a valid JavaThread; this check
 360         // is primarily for JVM_DumpThreads() which doesn't have a good
 361         // way to validate the _threads array.
 362         jt = NULL;
 363       }
 364       if (jt == NULL || /* thread not alive */
 365           jt->is_exiting() ||
 366           jt->is_hidden_from_external_view())  {
 367         // add a NULL snapshot if skipped
 368         _result->add_thread_snapshot();
 369         continue;
 370       }
 371       ThreadConcurrentLocks* tcl = NULL;
 372       if (_with_locked_synchronizers) {
 373         tcl = concurrent_locks.thread_concurrent_locks(jt);
 374       }
 375       snapshot_thread(jt, tcl);
 376     }
 377   }
 378 }
 379 
 380 void VM_ThreadDump::snapshot_thread(JavaThread* java_thread, ThreadConcurrentLocks* tcl) {
 381   ThreadSnapshot* snapshot = _result->add_thread_snapshot(java_thread);
 382   snapshot->dump_stack_at_safepoint(_max_depth, _with_locked_monitors);
 383   snapshot->set_concurrent_locks(tcl);
 384 }
 385 
 386 volatile bool VM_Exit::_vm_exited = false;
 387 Thread * volatile VM_Exit::_shutdown_thread = NULL;
 388 
 389 int VM_Exit::set_vm_exited() {
 390 
 391   Thread * thr_cur = Thread::current();
 392 
 393   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
 394 
 395   int num_active = 0;
 396 
 397   _shutdown_thread = thr_cur;
 398   _vm_exited = true;                                // global flag
 399   for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thr = jtiwh.next(); ) {
 400     if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
 401       ++num_active;
 402       thr->set_terminated(JavaThread::_vm_exited);  // per-thread flag
 403     }
 404   }
 405 
 406   return num_active;
 407 }
 408 
 409 int VM_Exit::wait_for_threads_in_native_to_block() {
 410   // VM exits at safepoint. This function must be called at the final safepoint
 411   // to wait for threads in _thread_in_native state to be quiescent.
 412   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
 413 
 414   Thread * thr_cur = Thread::current();
 415   Monitor timer(Mutex::leaf, "VM_Exit timer", true,
 416                 Monitor::_safepoint_check_never);
 417 
 418   // Compiler threads need longer wait because they can access VM data directly
 419   // while in native. If they are active and some structures being used are
 420   // deleted by the shutdown sequence, they will crash. On the other hand, user
 421   // threads must go through native=>Java/VM transitions first to access VM
 422   // data, and they will be stopped during state transition. In theory, we
 423   // don't have to wait for user threads to be quiescent, but it's always
 424   // better to terminate VM when current thread is the only active thread, so
 425   // wait for user threads too. Numbers are in 10 milliseconds.
 426   int max_wait_user_thread = 30;                  // at least 300 milliseconds
 427   int max_wait_compiler_thread = 1000;            // at least 10 seconds
 428 
 429   int max_wait = max_wait_compiler_thread;
 430 
 431   int attempts = 0;
 432   JavaThreadIteratorWithHandle jtiwh;
 433   while (true) {
 434     int num_active = 0;
 435     int num_active_compiler_thread = 0;
 436 
 437     jtiwh.rewind();
 438     for (; JavaThread *thr = jtiwh.next(); ) {
 439       if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
 440         num_active++;
 441         if (thr->is_Compiler_thread()) {
 442 #if INCLUDE_JVMCI
 443           CompilerThread* ct = (CompilerThread*) thr;
 444           if (ct->compiler() == NULL || !ct->compiler()->is_jvmci()) {
 445             num_active_compiler_thread++;
 446           } else {
 447             // A JVMCI compiler thread never accesses VM data structures
 448             // while in _thread_in_native state so there's no need to wait
 449             // for it and potentially add a 300 millisecond delay to VM
 450             // shutdown.
 451             num_active--;
 452           }
 453 #else
 454           num_active_compiler_thread++;
 455 #endif
 456         }
 457       }
 458     }
 459 
 460     if (num_active == 0) {
 461        return 0;
 462     } else if (attempts > max_wait) {
 463        return num_active;
 464     } else if (num_active_compiler_thread == 0 && attempts > max_wait_user_thread) {
 465        return num_active;
 466     }
 467 
 468     attempts++;
 469 
 470     MonitorLocker ml(&timer, Mutex::_no_safepoint_check_flag);
 471     ml.wait(10);
 472   }
 473 }
 474 
 475 bool VM_Exit::doit_prologue() {
 476   if (AsyncDeflateIdleMonitors && log_is_enabled(Info, monitorinflation)) {
 477     // AsyncDeflateIdleMonitors does a special deflation at the VM_Exit
 478     // safepoint in order to reduce the in-use monitor population that
 479     // is reported by ObjectSynchronizer::log_in_use_monitor_details()
 480     // at VM exit.
 481     ObjectSynchronizer::set_is_special_deflation_requested(true);
 482   }
 483   return true;
 484 }
 485 
 486 void VM_Exit::doit() {
 487 
 488   if (VerifyBeforeExit) {
 489     HandleMark hm(VMThread::vm_thread());
 490     // Among other things, this ensures that Eden top is correct.
 491     Universe::heap()->prepare_for_verify();
 492     // Silent verification so as not to pollute normal output,
 493     // unless we really asked for it.
 494     Universe::verify();
 495   }
 496 
 497   CompileBroker::set_should_block();
 498 
 499   // Wait for a short period for threads in native to block. Any thread
 500   // still executing native code after the wait will be stopped at
 501   // native==>Java/VM barriers.
 502   // Among 16276 JCK tests, 94% of them come here without any threads still
 503   // running in native; the other 6% are quiescent within 250ms (Ultra 80).
 504   wait_for_threads_in_native_to_block();
 505 
 506   set_vm_exited();
 507 
 508   // We'd like to call IdealGraphPrinter::clean_up() to finalize the
 509   // XML logging, but we can't safely do that here. The logic to make
 510   // XML termination logging safe is tied to the termination of the
 511   // VMThread, and it doesn't terminate on this exit path. See 8222534.
 512 
 513   // cleanup globals resources before exiting. exit_globals() currently
 514   // cleans up outputStream resources and PerfMemory resources.
 515   exit_globals();
 516 
 517   LogConfiguration::finalize();
 518 
 519   // Check for exit hook
 520   exit_hook_t exit_hook = Arguments::exit_hook();
 521   if (exit_hook != NULL) {
 522     // exit hook should exit.
 523     exit_hook(_exit_code);
 524     // ... but if it didn't, we must do it here
 525     vm_direct_exit(_exit_code);
 526   } else {
 527     vm_direct_exit(_exit_code);
 528   }
 529 }
 530 
 531 
 532 void VM_Exit::wait_if_vm_exited() {
 533   if (_vm_exited &&
 534       Thread::current_or_null() != _shutdown_thread) {
 535     // _vm_exited is set at safepoint, and the Threads_lock is never released
 536     // we will block here until the process dies
 537     Threads_lock->lock_without_safepoint_check();
 538     ShouldNotReachHere();
 539   }
 540 }
 541 
 542 void VM_PrintCompileQueue::doit() {
 543   CompileBroker::print_compile_queues(_out);
 544 }
 545 
 546 #if INCLUDE_SERVICES
 547 void VM_PrintClassHierarchy::doit() {
 548   KlassHierarchy::print_class_hierarchy(_out, _print_interfaces, _print_subclasses, _classname);
 549 }
 550 #endif