1 /*
   2  * Copyright (c) 1997, 2017, 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/isGCActiveMark.hpp"
  31 #include "logging/log.hpp"
  32 #include "logging/logStream.hpp"
  33 #include "memory/heapInspection.hpp"
  34 #include "memory/resourceArea.hpp"
  35 #include "oops/symbol.hpp"
  36 #include "runtime/arguments.hpp"
  37 #include "runtime/deoptimization.hpp"
  38 #include "runtime/interfaceSupport.hpp"
  39 #include "runtime/sweeper.hpp"
  40 #include "runtime/thread.inline.hpp"
  41 #include "runtime/threadSMR.inline.hpp"
  42 #include "runtime/vm_operations.hpp"
  43 #include "services/threadService.hpp"
  44 #include "trace/tracing.hpp"
  45 
  46 #define VM_OP_NAME_INITIALIZE(name) #name,
  47 
  48 const char* VM_Operation::_names[VM_Operation::VMOp_Terminating] = \
  49   { VM_OPS_DO(VM_OP_NAME_INITIALIZE) };
  50 
  51 void VM_Operation::set_calling_thread(Thread* thread, ThreadPriority priority) {
  52   _calling_thread = thread;
  53   assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
  54   _priority = priority;
  55 }
  56 
  57 
  58 void VM_Operation::evaluate() {
  59   ResourceMark rm;
  60   LogTarget(Debug, vmoperation) lt;
  61   if (lt.is_enabled()) {
  62     LogStream ls(lt);
  63     ls.print("begin ");
  64     print_on_error(&ls);
  65     ls.cr();
  66   }
  67   doit();
  68   if (lt.is_enabled()) {
  69     LogStream ls(lt);
  70     ls.print("end ");
  71     print_on_error(&ls);
  72     ls.cr();
  73   }
  74 }
  75 
  76 const char* VM_Operation::mode_to_string(Mode mode) {
  77   switch(mode) {
  78     case _safepoint      : return "safepoint";
  79     case _no_safepoint   : return "no safepoint";
  80     case _concurrent     : return "concurrent";
  81     case _async_safepoint: return "async safepoint";
  82     default              : return "unknown";
  83   }
  84 }
  85 // Called by fatal error handler.
  86 void VM_Operation::print_on_error(outputStream* st) const {
  87   st->print("VM_Operation (" PTR_FORMAT "): ", p2i(this));
  88   st->print("%s", name());
  89 
  90   const char* mode = mode_to_string(evaluation_mode());
  91   st->print(", mode: %s", mode);
  92 
  93   if (calling_thread()) {
  94     st->print(", requested by thread " PTR_FORMAT, p2i(calling_thread()));
  95   }
  96 }
  97 
  98 void VM_ThreadStop::doit() {
  99   assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
 100   ThreadsListHandle tlh;
 101   JavaThread* target = java_lang_Thread::thread(target_thread());
 102   // Note that this now allows multiple ThreadDeath exceptions to be
 103   // thrown at a thread.
 104   if (target != NULL && (!EnableThreadSMRExtraValidityChecks || tlh.includes(target))) {
 105     // The target thread has run and has not exited yet.
 106     target->send_thread_stop(throwable());
 107   }
 108 }
 109 
 110 void VM_ClearICs::doit() {
 111   if (_preserve_static_stubs) {
 112     CodeCache::cleanup_inline_caches();
 113   } else {
 114     CodeCache::clear_inline_caches();
 115   }
 116 }
 117 
 118 void VM_Deoptimize::doit() {
 119   // We do not want any GCs to happen while we are in the middle of this VM operation
 120   ResourceMark rm;
 121   DeoptimizationMarker dm;
 122 
 123   // Deoptimize all activations depending on marked nmethods
 124   Deoptimization::deoptimize_dependents();
 125 
 126   // Make the dependent methods not entrant
 127   CodeCache::make_marked_nmethods_not_entrant();
 128 }
 129 
 130 void VM_MarkActiveNMethods::doit() {
 131   NMethodSweeper::mark_active_nmethods();
 132 }
 133 
 134 VM_DeoptimizeFrame::VM_DeoptimizeFrame(JavaThread* thread, intptr_t* id, int reason) {
 135   _thread = thread;
 136   _id     = id;
 137   _reason = reason;
 138 }
 139 
 140 
 141 void VM_DeoptimizeFrame::doit() {
 142   assert(_reason > Deoptimization::Reason_none && _reason < Deoptimization::Reason_LIMIT, "invalid deopt reason");
 143   Deoptimization::deoptimize_frame_internal(_thread, _id, (Deoptimization::DeoptReason)_reason);
 144 }
 145 
 146 
 147 #ifndef PRODUCT
 148 
 149 void VM_DeoptimizeAll::doit() {
 150   DeoptimizationMarker dm;
 151   JavaThreadIteratorWithHandle jtiwh;
 152   // deoptimize all java threads in the system
 153   if (DeoptimizeALot) {
 154     for (; JavaThread *thread = jtiwh.next(); ) {
 155       if (thread->has_last_Java_frame()) {
 156         thread->deoptimize();
 157       }
 158     }
 159   } else if (DeoptimizeRandom) {
 160 
 161     // Deoptimize some selected threads and frames
 162     int tnum = os::random() & 0x3;
 163     int fnum =  os::random() & 0x3;
 164     int tcount = 0;
 165     for (; JavaThread *thread = jtiwh.next(); ) {
 166       if (thread->has_last_Java_frame()) {
 167         if (tcount++ == tnum)  {
 168         tcount = 0;
 169           int fcount = 0;
 170           // Deoptimize some selected frames.
 171           // Biased llocking wants a updated register map
 172           for(StackFrameStream fst(thread, UseBiasedLocking); !fst.is_done(); fst.next()) {
 173             if (fst.current()->can_be_deoptimized()) {
 174               if (fcount++ == fnum) {
 175                 fcount = 0;
 176                 Deoptimization::deoptimize(thread, *fst.current(), fst.register_map());
 177               }
 178             }
 179           }
 180         }
 181       }
 182     }
 183   }
 184 }
 185 
 186 
 187 void VM_ZombieAll::doit() {
 188   JavaThread *thread = (JavaThread *)calling_thread();
 189   assert(thread->is_Java_thread(), "must be a Java thread");
 190   thread->make_zombies();
 191 }
 192 
 193 #endif // !PRODUCT
 194 
 195 void VM_UnlinkSymbols::doit() {
 196   JavaThread *thread = (JavaThread *)calling_thread();
 197   assert(thread->is_Java_thread(), "must be a Java thread");
 198   SymbolTable::unlink();
 199 }
 200 
 201 void VM_Verify::doit() {
 202   Universe::heap()->prepare_for_verify();
 203   Universe::verify();
 204 }
 205 
 206 bool VM_PrintThreads::doit_prologue() {
 207   // Make sure AbstractOwnableSynchronizer is loaded
 208   JavaThread* jt = JavaThread::current();
 209   java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(jt);
 210   if (jt->has_pending_exception()) {
 211     return false;
 212   }
 213 
 214   // Get Heap_lock if concurrent locks will be dumped
 215   if (_print_concurrent_locks) {
 216     Heap_lock->lock();
 217   }
 218   return true;
 219 }
 220 
 221 void VM_PrintThreads::doit() {
 222   Threads::print_on(_out, true, false, _print_concurrent_locks);
 223 }
 224 
 225 void VM_PrintThreads::doit_epilogue() {
 226   if (_print_concurrent_locks) {
 227     // Release Heap_lock
 228     Heap_lock->unlock();
 229   }
 230 }
 231 
 232 void VM_PrintJNI::doit() {
 233   JNIHandles::print_on(_out);
 234 }
 235 
 236 void VM_PrintMetadata::doit() {
 237   MetaspaceUtils::print_metadata_for_nmt(_out, _scale);
 238 }
 239 
 240 VM_FindDeadlocks::~VM_FindDeadlocks() {
 241   if (_deadlocks != NULL) {
 242     DeadlockCycle* cycle = _deadlocks;
 243     while (cycle != NULL) {
 244       DeadlockCycle* d = cycle;
 245       cycle = cycle->next();
 246       delete d;
 247     }
 248   }
 249 }
 250 
 251 bool VM_FindDeadlocks::doit_prologue() {
 252   if (_concurrent_locks) {
 253     // Make sure AbstractOwnableSynchronizer is loaded
 254     JavaThread* jt = JavaThread::current();
 255     java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(jt);
 256     if (jt->has_pending_exception()) {
 257       return false;
 258     }
 259   }
 260 
 261   return true;
 262 }
 263 
 264 void VM_FindDeadlocks::doit() {
 265   // Update the hazard ptr in the originating thread to the current
 266   // list of threads. This VM operation needs the current list of
 267   // threads for proper deadlock detection and those are the
 268   // JavaThreads we need to be protected when we return info to the
 269   // originating thread.
 270   _setter.set();
 271 
 272   _deadlocks = ThreadService::find_deadlocks_at_safepoint(_setter.list(), _concurrent_locks);
 273   if (_out != NULL) {
 274     int num_deadlocks = 0;
 275     for (DeadlockCycle* cycle = _deadlocks; cycle != NULL; cycle = cycle->next()) {
 276       num_deadlocks++;
 277       cycle->print_on_with(_setter.list(), _out);
 278     }
 279 
 280     if (num_deadlocks == 1) {
 281       _out->print_cr("\nFound 1 deadlock.\n");
 282       _out->flush();
 283     } else if (num_deadlocks > 1) {
 284       _out->print_cr("\nFound %d deadlocks.\n", num_deadlocks);
 285       _out->flush();
 286     }
 287   }
 288 }
 289 
 290 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
 291                              int max_depth,
 292                              bool with_locked_monitors,
 293                              bool with_locked_synchronizers) {
 294   _result = result;
 295   _num_threads = 0; // 0 indicates all threads
 296   _threads = NULL;
 297   _result = result;
 298   _max_depth = max_depth;
 299   _with_locked_monitors = with_locked_monitors;
 300   _with_locked_synchronizers = with_locked_synchronizers;
 301 }
 302 
 303 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
 304                              GrowableArray<instanceHandle>* threads,
 305                              int num_threads,
 306                              int max_depth,
 307                              bool with_locked_monitors,
 308                              bool with_locked_synchronizers) {
 309   _result = result;
 310   _num_threads = num_threads;
 311   _threads = threads;
 312   _result = result;
 313   _max_depth = max_depth;
 314   _with_locked_monitors = with_locked_monitors;
 315   _with_locked_synchronizers = with_locked_synchronizers;
 316 }
 317 
 318 bool VM_ThreadDump::doit_prologue() {
 319   // Make sure AbstractOwnableSynchronizer is loaded
 320   JavaThread* jt = JavaThread::current();
 321   java_util_concurrent_locks_AbstractOwnableSynchronizer::initialize(jt);
 322   if (jt->has_pending_exception()) {
 323     return false;
 324   }
 325 
 326   if (_with_locked_synchronizers) {
 327     // Acquire Heap_lock to dump concurrent locks
 328     Heap_lock->lock();
 329   }
 330 
 331   return true;
 332 }
 333 
 334 void VM_ThreadDump::doit_epilogue() {
 335   if (_with_locked_synchronizers) {
 336     // Release Heap_lock
 337     Heap_lock->unlock();
 338   }
 339 }
 340 
 341 void VM_ThreadDump::doit() {
 342   ResourceMark rm;
 343 
 344   // Set the hazard ptr in the originating thread to protect the
 345   // current list of threads. This VM operation needs the current list
 346   // of threads for a proper dump and those are the JavaThreads we need
 347   // to be protected when we return info to the originating thread.
 348   _result->set_t_list();
 349 
 350   ConcurrentLocksDump concurrent_locks(true);
 351   if (_with_locked_synchronizers) {
 352     concurrent_locks.dump_at_safepoint();
 353   }
 354 
 355   if (_num_threads == 0) {
 356     // Snapshot all live threads
 357 
 358     for (uint i = 0; i < _result->t_list()->length(); i++) {
 359       JavaThread* jt = _result->t_list()->thread_at(i);
 360       if (jt->is_exiting() ||
 361           jt->is_hidden_from_external_view())  {
 362         // skip terminating threads and hidden threads
 363         continue;
 364       }
 365       ThreadConcurrentLocks* tcl = NULL;
 366       if (_with_locked_synchronizers) {
 367         tcl = concurrent_locks.thread_concurrent_locks(jt);
 368       }
 369       ThreadSnapshot* ts = snapshot_thread(jt, tcl);
 370       _result->add_thread_snapshot(ts);
 371     }
 372   } else {
 373     // Snapshot threads in the given _threads array
 374     // A dummy snapshot is created if a thread doesn't exist
 375 
 376     for (int i = 0; i < _num_threads; i++) {
 377       instanceHandle th = _threads->at(i);
 378       if (th() == NULL) {
 379         // skip if the thread doesn't exist
 380         // Add a dummy snapshot
 381         _result->add_thread_snapshot(new ThreadSnapshot());
 382         continue;
 383       }
 384 
 385       // Dump thread stack only if the thread is alive and not exiting
 386       // and not VM internal thread.
 387       JavaThread* jt = java_lang_Thread::thread(th());
 388       if (jt != NULL && !_result->t_list()->includes(jt)) {
 389         // _threads[i] doesn't refer to a valid JavaThread; this check
 390         // is primarily for JVM_DumpThreads() which doesn't have a good
 391         // way to validate the _threads array.
 392         jt = NULL;
 393       }
 394       if (jt == NULL || /* thread not alive */
 395           jt->is_exiting() ||
 396           jt->is_hidden_from_external_view())  {
 397         // add a NULL snapshot if skipped
 398         _result->add_thread_snapshot(new ThreadSnapshot());
 399         continue;
 400       }
 401       ThreadConcurrentLocks* tcl = NULL;
 402       if (_with_locked_synchronizers) {
 403         tcl = concurrent_locks.thread_concurrent_locks(jt);
 404       }
 405       ThreadSnapshot* ts = snapshot_thread(jt, tcl);
 406       _result->add_thread_snapshot(ts);
 407     }
 408   }
 409 }
 410 
 411 ThreadSnapshot* VM_ThreadDump::snapshot_thread(JavaThread* java_thread, ThreadConcurrentLocks* tcl) {
 412   ThreadSnapshot* snapshot = new ThreadSnapshot(_result->t_list(), java_thread);
 413   snapshot->dump_stack_at_safepoint(_max_depth, _with_locked_monitors);
 414   snapshot->set_concurrent_locks(tcl);
 415   return snapshot;
 416 }
 417 
 418 volatile bool VM_Exit::_vm_exited = false;
 419 Thread * VM_Exit::_shutdown_thread = NULL;
 420 
 421 int VM_Exit::set_vm_exited() {
 422 
 423   Thread * thr_cur = Thread::current();
 424 
 425   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
 426 
 427   int num_active = 0;
 428 
 429   _shutdown_thread = thr_cur;
 430   _vm_exited = true;                                // global flag
 431   for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thr = jtiwh.next(); ) {
 432     if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
 433       ++num_active;
 434       thr->set_terminated(JavaThread::_vm_exited);  // per-thread flag
 435     }
 436   }
 437 
 438   return num_active;
 439 }
 440 
 441 int VM_Exit::wait_for_threads_in_native_to_block() {
 442   // VM exits at safepoint. This function must be called at the final safepoint
 443   // to wait for threads in _thread_in_native state to be quiescent.
 444   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
 445 
 446   Thread * thr_cur = Thread::current();
 447   Monitor timer(Mutex::leaf, "VM_Exit timer", true,
 448                 Monitor::_safepoint_check_never);
 449 
 450   // Compiler threads need longer wait because they can access VM data directly
 451   // while in native. If they are active and some structures being used are
 452   // deleted by the shutdown sequence, they will crash. On the other hand, user
 453   // threads must go through native=>Java/VM transitions first to access VM
 454   // data, and they will be stopped during state transition. In theory, we
 455   // don't have to wait for user threads to be quiescent, but it's always
 456   // better to terminate VM when current thread is the only active thread, so
 457   // wait for user threads too. Numbers are in 10 milliseconds.
 458   int max_wait_user_thread = 30;                  // at least 300 milliseconds
 459   int max_wait_compiler_thread = 1000;            // at least 10 seconds
 460 
 461   int max_wait = max_wait_compiler_thread;
 462 
 463   int attempts = 0;
 464   JavaThreadIteratorWithHandle jtiwh;
 465   while (true) {
 466     int num_active = 0;
 467     int num_active_compiler_thread = 0;
 468 
 469     jtiwh.rewind();
 470     for (; JavaThread *thr = jtiwh.next(); ) {
 471       if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
 472         num_active++;
 473         if (thr->is_Compiler_thread()) {
 474           num_active_compiler_thread++;
 475         }
 476       }
 477     }
 478 
 479     if (num_active == 0) {
 480        return 0;
 481     } else if (attempts > max_wait) {
 482        return num_active;
 483     } else if (num_active_compiler_thread == 0 && attempts > max_wait_user_thread) {
 484        return num_active;
 485     }
 486 
 487     attempts++;
 488 
 489     MutexLockerEx ml(&timer, Mutex::_no_safepoint_check_flag);
 490     timer.wait(Mutex::_no_safepoint_check_flag, 10);
 491   }
 492 }
 493 
 494 void VM_Exit::doit() {
 495   CompileBroker::set_should_block();
 496 
 497   // Wait for a short period for threads in native to block. Any thread
 498   // still executing native code after the wait will be stopped at
 499   // native==>Java/VM barriers.
 500   // Among 16276 JCK tests, 94% of them come here without any threads still
 501   // running in native; the other 6% are quiescent within 250ms (Ultra 80).
 502   wait_for_threads_in_native_to_block();
 503 
 504   set_vm_exited();
 505 
 506   // cleanup globals resources before exiting. exit_globals() currently
 507   // cleans up outputStream resources and PerfMemory resources.
 508   exit_globals();
 509 
 510   // Check for exit hook
 511   exit_hook_t exit_hook = Arguments::exit_hook();
 512   if (exit_hook != NULL) {
 513     // exit hook should exit.
 514     exit_hook(_exit_code);
 515     // ... but if it didn't, we must do it here
 516     vm_direct_exit(_exit_code);
 517   } else {
 518     vm_direct_exit(_exit_code);
 519   }
 520 }
 521 
 522 
 523 void VM_Exit::wait_if_vm_exited() {
 524   if (_vm_exited &&
 525       Thread::current_or_null() != _shutdown_thread) {
 526     // _vm_exited is set at safepoint, and the Threads_lock is never released
 527     // we will block here until the process dies
 528     Threads_lock->lock_without_safepoint_check();
 529     ShouldNotReachHere();
 530   }
 531 }
 532 
 533 void VM_PrintCompileQueue::doit() {
 534   CompileBroker::print_compile_queues(_out);
 535 }
 536 
 537 #if INCLUDE_SERVICES
 538 void VM_PrintClassHierarchy::doit() {
 539   KlassHierarchy::print_class_hierarchy(_out, _print_interfaces, _print_subclasses, _classname);
 540 }
 541 #endif