1 /*
   2  * Copyright (c) 1997, 2020, 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/metaspace/metaspaceReport.hpp"
  37 #include "memory/resourceArea.hpp"
  38 #include "memory/universe.hpp"
  39 #include "oops/symbol.hpp"
  40 #include "runtime/arguments.hpp"
  41 #include "runtime/deoptimization.hpp"
  42 #include "runtime/frame.inline.hpp"
  43 #include "runtime/interfaceSupport.inline.hpp"
  44 #include "runtime/sweeper.hpp"
  45 #include "runtime/synchronizer.hpp"
  46 #include "runtime/thread.inline.hpp"
  47 #include "runtime/threadSMR.inline.hpp"
  48 #include "runtime/vmOperations.hpp"
  49 #include "services/threadService.hpp"
  50 
  51 #define VM_OP_NAME_INITIALIZE(name) #name,
  52 
  53 const char* VM_Operation::_names[VM_Operation::VMOp_Terminating] = \
  54   { VM_OPS_DO(VM_OP_NAME_INITIALIZE) };
  55 
  56 void VM_Operation::set_calling_thread(Thread* thread) {
  57   _calling_thread = thread;
  58 }
  59 
  60 void VM_Operation::evaluate() {
  61   ResourceMark rm;
  62   LogTarget(Debug, vmoperation) lt;
  63   if (lt.is_enabled()) {
  64     LogStream ls(lt);
  65     ls.print("begin ");
  66     print_on_error(&ls);
  67     ls.cr();
  68   }
  69   doit();
  70   if (lt.is_enabled()) {
  71     LogStream ls(lt);
  72     ls.print("end ");
  73     print_on_error(&ls);
  74     ls.cr();
  75   }
  76 }
  77 
  78 // Called by fatal error handler.
  79 void VM_Operation::print_on_error(outputStream* st) const {
  80   st->print("VM_Operation (" PTR_FORMAT "): ", p2i(this));
  81   st->print("%s", name());
  82 
  83   st->print(", mode: %s", evaluate_at_safepoint() ? "safepoint" : "no safepoint");
  84 
  85   if (calling_thread()) {
  86     st->print(", requested by thread " PTR_FORMAT, p2i(calling_thread()));
  87   }
  88 }
  89 
  90 void VM_ClearICs::doit() {
  91   if (_preserve_static_stubs) {
  92     CodeCache::cleanup_inline_caches();
  93   } else {
  94     CodeCache::clear_inline_caches();
  95   }
  96 }
  97 
  98 VM_DeoptimizeFrame::VM_DeoptimizeFrame(JavaThread* thread, intptr_t* id, int reason) {
  99   _thread = thread;
 100   _id     = id;
 101   _reason = reason;
 102 }
 103 
 104 
 105 void VM_DeoptimizeFrame::doit() {
 106   assert(_reason > Deoptimization::Reason_none && _reason < Deoptimization::Reason_LIMIT, "invalid deopt reason");
 107   Deoptimization::deoptimize_frame_internal(_thread, _id, (Deoptimization::DeoptReason)_reason);
 108 }
 109 
 110 
 111 #ifndef PRODUCT
 112 
 113 void VM_DeoptimizeAll::doit() {
 114   DeoptimizationMarker dm;
 115   JavaThreadIteratorWithHandle jtiwh;
 116   // deoptimize all java threads in the system
 117   if (DeoptimizeALot) {
 118     for (; JavaThread *thread = jtiwh.next(); ) {
 119       if (thread->has_last_Java_frame()) {
 120         thread->deoptimize();
 121       }
 122     }
 123   } else if (DeoptimizeRandom) {
 124 
 125     // Deoptimize some selected threads and frames
 126     int tnum = os::random() & 0x3;
 127     int fnum =  os::random() & 0x3;
 128     int tcount = 0;
 129     for (; JavaThread *thread = jtiwh.next(); ) {
 130       if (thread->has_last_Java_frame()) {
 131         if (tcount++ == tnum)  {
 132         tcount = 0;
 133           int fcount = 0;
 134           // Deoptimize some selected frames.
 135           for(StackFrameStream fst(thread, false); !fst.is_done(); fst.next()) {
 136             if (fst.current()->can_be_deoptimized()) {
 137               if (fcount++ == fnum) {
 138                 fcount = 0;
 139                 Deoptimization::deoptimize(thread, *fst.current());
 140               }
 141             }
 142           }
 143         }
 144       }
 145     }
 146   }
 147 }
 148 
 149 
 150 void VM_ZombieAll::doit() {
 151   JavaThread *thread = (JavaThread *)calling_thread();
 152   assert(thread->is_Java_thread(), "must be a Java thread");
 153   thread->make_zombies();
 154 }
 155 
 156 #endif // !PRODUCT
 157 
 158 void VM_Verify::doit() {
 159   Universe::heap()->prepare_for_verify();
 160   Universe::verify();
 161 }
 162 
 163 bool VM_PrintThreads::doit_prologue() {
 164   // Get Heap_lock if concurrent locks will be dumped
 165   if (_print_concurrent_locks) {
 166     Heap_lock->lock();
 167   }
 168   return true;
 169 }
 170 
 171 void VM_PrintThreads::doit() {
 172   Threads::print_on(_out, true, false, _print_concurrent_locks, _print_extended_info);
 173 }
 174 
 175 void VM_PrintThreads::doit_epilogue() {
 176   if (_print_concurrent_locks) {
 177     // Release Heap_lock
 178     Heap_lock->unlock();
 179   }
 180 }
 181 
 182 void VM_PrintJNI::doit() {
 183   JNIHandles::print_on(_out);
 184 }
 185 
 186 void VM_PrintMetadata::doit() {
 187   metaspace::MetaspaceReporter::print_report(_out, _scale, _flags);
 188 }
 189 
 190 VM_FindDeadlocks::~VM_FindDeadlocks() {
 191   if (_deadlocks != NULL) {
 192     DeadlockCycle* cycle = _deadlocks;
 193     while (cycle != NULL) {
 194       DeadlockCycle* d = cycle;
 195       cycle = cycle->next();
 196       delete d;
 197     }
 198   }
 199 }
 200 
 201 void VM_FindDeadlocks::doit() {
 202   // Update the hazard ptr in the originating thread to the current
 203   // list of threads. This VM operation needs the current list of
 204   // threads for proper deadlock detection and those are the
 205   // JavaThreads we need to be protected when we return info to the
 206   // originating thread.
 207   _setter.set();
 208 
 209   _deadlocks = ThreadService::find_deadlocks_at_safepoint(_setter.list(), _concurrent_locks);
 210   if (_out != NULL) {
 211     int num_deadlocks = 0;
 212     for (DeadlockCycle* cycle = _deadlocks; cycle != NULL; cycle = cycle->next()) {
 213       num_deadlocks++;
 214       cycle->print_on_with(_setter.list(), _out);
 215     }
 216 
 217     if (num_deadlocks == 1) {
 218       _out->print_cr("\nFound 1 deadlock.\n");
 219       _out->flush();
 220     } else if (num_deadlocks > 1) {
 221       _out->print_cr("\nFound %d deadlocks.\n", num_deadlocks);
 222       _out->flush();
 223     }
 224   }
 225 }
 226 
 227 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
 228                              int max_depth,
 229                              bool with_locked_monitors,
 230                              bool with_locked_synchronizers) {
 231   _result = result;
 232   _num_threads = 0; // 0 indicates all threads
 233   _threads = NULL;
 234   _result = result;
 235   _max_depth = max_depth;
 236   _with_locked_monitors = with_locked_monitors;
 237   _with_locked_synchronizers = with_locked_synchronizers;
 238 }
 239 
 240 VM_ThreadDump::VM_ThreadDump(ThreadDumpResult* result,
 241                              GrowableArray<instanceHandle>* threads,
 242                              int num_threads,
 243                              int max_depth,
 244                              bool with_locked_monitors,
 245                              bool with_locked_synchronizers) {
 246   _result = result;
 247   _num_threads = num_threads;
 248   _threads = threads;
 249   _result = result;
 250   _max_depth = max_depth;
 251   _with_locked_monitors = with_locked_monitors;
 252   _with_locked_synchronizers = with_locked_synchronizers;
 253 }
 254 
 255 bool VM_ThreadDump::doit_prologue() {
 256   if (_with_locked_synchronizers) {
 257     // Acquire Heap_lock to dump concurrent locks
 258     Heap_lock->lock();
 259   }
 260 
 261   return true;
 262 }
 263 
 264 void VM_ThreadDump::doit_epilogue() {
 265   if (_with_locked_synchronizers) {
 266     // Release Heap_lock
 267     Heap_lock->unlock();
 268   }
 269 }
 270 
 271 void VM_ThreadDump::doit() {
 272   ResourceMark rm;
 273 
 274   // Set the hazard ptr in the originating thread to protect the
 275   // current list of threads. This VM operation needs the current list
 276   // of threads for a proper dump and those are the JavaThreads we need
 277   // to be protected when we return info to the originating thread.
 278   _result->set_t_list();
 279 
 280   ConcurrentLocksDump concurrent_locks(true);
 281   if (_with_locked_synchronizers) {
 282     concurrent_locks.dump_at_safepoint();
 283   }
 284 
 285   if (_num_threads == 0) {
 286     // Snapshot all live threads
 287 
 288     for (uint i = 0; i < _result->t_list()->length(); i++) {
 289       JavaThread* jt = _result->t_list()->thread_at(i);
 290       if (jt->is_exiting() ||
 291           jt->is_hidden_from_external_view())  {
 292         // skip terminating threads and hidden threads
 293         continue;
 294       }
 295       ThreadConcurrentLocks* tcl = NULL;
 296       if (_with_locked_synchronizers) {
 297         tcl = concurrent_locks.thread_concurrent_locks(jt);
 298       }
 299       snapshot_thread(jt, tcl);
 300     }
 301   } else {
 302     // Snapshot threads in the given _threads array
 303     // A dummy snapshot is created if a thread doesn't exist
 304 
 305     for (int i = 0; i < _num_threads; i++) {
 306       instanceHandle th = _threads->at(i);
 307       if (th() == NULL) {
 308         // skip if the thread doesn't exist
 309         // Add a dummy snapshot
 310         _result->add_thread_snapshot();
 311         continue;
 312       }
 313 
 314       // Dump thread stack only if the thread is alive and not exiting
 315       // and not VM internal thread.
 316       JavaThread* jt = java_lang_Thread::thread(th());
 317       if (jt != NULL && !_result->t_list()->includes(jt)) {
 318         // _threads[i] doesn't refer to a valid JavaThread; this check
 319         // is primarily for JVM_DumpThreads() which doesn't have a good
 320         // way to validate the _threads array.
 321         jt = NULL;
 322       }
 323       if (jt == NULL || /* thread not alive */
 324           jt->is_exiting() ||
 325           jt->is_hidden_from_external_view())  {
 326         // add a NULL snapshot if skipped
 327         _result->add_thread_snapshot();
 328         continue;
 329       }
 330       ThreadConcurrentLocks* tcl = NULL;
 331       if (_with_locked_synchronizers) {
 332         tcl = concurrent_locks.thread_concurrent_locks(jt);
 333       }
 334       snapshot_thread(jt, tcl);
 335     }
 336   }
 337 }
 338 
 339 void VM_ThreadDump::snapshot_thread(JavaThread* java_thread, ThreadConcurrentLocks* tcl) {
 340   ThreadSnapshot* snapshot = _result->add_thread_snapshot(java_thread);
 341   snapshot->dump_stack_at_safepoint(_max_depth, _with_locked_monitors);
 342   snapshot->set_concurrent_locks(tcl);
 343 }
 344 
 345 volatile bool VM_Exit::_vm_exited = false;
 346 Thread * volatile VM_Exit::_shutdown_thread = NULL;
 347 
 348 int VM_Exit::set_vm_exited() {
 349 
 350   Thread * thr_cur = Thread::current();
 351 
 352   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
 353 
 354   int num_active = 0;
 355 
 356   _shutdown_thread = thr_cur;
 357   _vm_exited = true;                                // global flag
 358   for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thr = jtiwh.next(); ) {
 359     if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
 360       ++num_active;
 361       thr->set_terminated(JavaThread::_vm_exited);  // per-thread flag
 362     }
 363   }
 364 
 365   return num_active;
 366 }
 367 
 368 int VM_Exit::wait_for_threads_in_native_to_block() {
 369   // VM exits at safepoint. This function must be called at the final safepoint
 370   // to wait for threads in _thread_in_native state to be quiescent.
 371   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint already");
 372 
 373   Thread * thr_cur = Thread::current();
 374   Monitor timer(Mutex::leaf, "VM_Exit timer", true,
 375                 Monitor::_safepoint_check_never);
 376 
 377   // Compiler threads need longer wait because they can access VM data directly
 378   // while in native. If they are active and some structures being used are
 379   // deleted by the shutdown sequence, they will crash. On the other hand, user
 380   // threads must go through native=>Java/VM transitions first to access VM
 381   // data, and they will be stopped during state transition. In theory, we
 382   // don't have to wait for user threads to be quiescent, but it's always
 383   // better to terminate VM when current thread is the only active thread, so
 384   // wait for user threads too. Numbers are in 10 milliseconds.
 385   int max_wait_user_thread = 30;                  // at least 300 milliseconds
 386   int max_wait_compiler_thread = 1000;            // at least 10 seconds
 387 
 388   int max_wait = max_wait_compiler_thread;
 389 
 390   int attempts = 0;
 391   JavaThreadIteratorWithHandle jtiwh;
 392   while (true) {
 393     int num_active = 0;
 394     int num_active_compiler_thread = 0;
 395 
 396     jtiwh.rewind();
 397     for (; JavaThread *thr = jtiwh.next(); ) {
 398       if (thr!=thr_cur && thr->thread_state() == _thread_in_native) {
 399         num_active++;
 400         if (thr->is_Compiler_thread()) {
 401 #if INCLUDE_JVMCI
 402           CompilerThread* ct = (CompilerThread*) thr;
 403           if (ct->compiler() == NULL || !ct->compiler()->is_jvmci()) {
 404             num_active_compiler_thread++;
 405           } else {
 406             // A JVMCI compiler thread never accesses VM data structures
 407             // while in _thread_in_native state so there's no need to wait
 408             // for it and potentially add a 300 millisecond delay to VM
 409             // shutdown.
 410             num_active--;
 411           }
 412 #else
 413           num_active_compiler_thread++;
 414 #endif
 415         }
 416       }
 417     }
 418 
 419     if (num_active == 0) {
 420        return 0;
 421     } else if (attempts > max_wait) {
 422        return num_active;
 423     } else if (num_active_compiler_thread == 0 && attempts > max_wait_user_thread) {
 424        return num_active;
 425     }
 426 
 427     attempts++;
 428 
 429     MonitorLocker ml(&timer, Mutex::_no_safepoint_check_flag);
 430     ml.wait(10);
 431   }
 432 }
 433 
 434 bool VM_Exit::doit_prologue() {
 435   if (log_is_enabled(Info, monitorinflation)) {
 436     // Do a deflation in order to reduce the in-use monitor population
 437     // that is reported by ObjectSynchronizer::log_in_use_monitor_details()
 438     // at VM exit.
 439     ObjectSynchronizer::request_deflate_idle_monitors();
 440   }
 441   return true;
 442 }
 443 
 444 void VM_Exit::doit() {
 445 
 446   if (VerifyBeforeExit) {
 447     HandleMark hm(VMThread::vm_thread());
 448     // Among other things, this ensures that Eden top is correct.
 449     Universe::heap()->prepare_for_verify();
 450     // Silent verification so as not to pollute normal output,
 451     // unless we really asked for it.
 452     Universe::verify();
 453   }
 454 
 455   CompileBroker::set_should_block();
 456 
 457   // Wait for a short period for threads in native to block. Any thread
 458   // still executing native code after the wait will be stopped at
 459   // native==>Java/VM barriers.
 460   // Among 16276 JCK tests, 94% of them come here without any threads still
 461   // running in native; the other 6% are quiescent within 250ms (Ultra 80).
 462   wait_for_threads_in_native_to_block();
 463 
 464   set_vm_exited();
 465 
 466   // We'd like to call IdealGraphPrinter::clean_up() to finalize the
 467   // XML logging, but we can't safely do that here. The logic to make
 468   // XML termination logging safe is tied to the termination of the
 469   // VMThread, and it doesn't terminate on this exit path. See 8222534.
 470 
 471   // cleanup globals resources before exiting. exit_globals() currently
 472   // cleans up outputStream resources and PerfMemory resources.
 473   exit_globals();
 474 
 475   LogConfiguration::finalize();
 476 
 477   // Check for exit hook
 478   exit_hook_t exit_hook = Arguments::exit_hook();
 479   if (exit_hook != NULL) {
 480     // exit hook should exit.
 481     exit_hook(_exit_code);
 482     // ... but if it didn't, we must do it here
 483     vm_direct_exit(_exit_code);
 484   } else {
 485     vm_direct_exit(_exit_code);
 486   }
 487 }
 488 
 489 
 490 void VM_Exit::wait_if_vm_exited() {
 491   if (_vm_exited &&
 492       Thread::current_or_null() != _shutdown_thread) {
 493     // _vm_exited is set at safepoint, and the Threads_lock is never released
 494     // we will block here until the process dies
 495     Threads_lock->lock();
 496     ShouldNotReachHere();
 497   }
 498 }
 499 
 500 void VM_PrintCompileQueue::doit() {
 501   CompileBroker::print_compile_queues(_out);
 502 }
 503 
 504 #if INCLUDE_SERVICES
 505 void VM_PrintClassHierarchy::doit() {
 506   KlassHierarchy::print_class_hierarchy(_out, _print_interfaces, _print_subclasses, _classname);
 507 }
 508 #endif