1 /*
2 * Copyright (c) 1997, 2022, 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 "jvm.h"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/javaThreadStatus.hpp"
30 #include "gc/shared/barrierSet.hpp"
31 #include "jfr/jfrEvents.hpp"
32 #include "jvmtifiles/jvmtiEnv.hpp"
33 #include "logging/log.hpp"
34 #include "memory/allocation.inline.hpp"
35 #include "memory/iterator.hpp"
36 #include "memory/resourceArea.hpp"
37 #include "oops/oop.inline.hpp"
38 #include "runtime/atomic.hpp"
39 #include "runtime/handles.inline.hpp"
40 #include "runtime/javaThread.inline.hpp"
41 #include "runtime/lockStack.inline.hpp"
42 #include "runtime/nonJavaThread.hpp"
43 #include "runtime/orderAccess.hpp"
44 #include "runtime/osThread.hpp"
45 #include "runtime/safepoint.hpp"
46 #include "runtime/safepointMechanism.inline.hpp"
47 #include "runtime/thread.inline.hpp"
48 #include "runtime/threadSMR.inline.hpp"
49 #include "services/memTracker.hpp"
50 #include "utilities/macros.hpp"
51 #include "utilities/spinYield.hpp"
52 #if INCLUDE_JFR
53 #include "jfr/jfr.hpp"
54 #endif
55
56 #ifndef USE_LIBRARY_BASED_TLS_ONLY
57 // Current thread is maintained as a thread-local variable
58 THREAD_LOCAL Thread* Thread::_thr_current = NULL;
59 #endif
60
61 // ======= Thread ========
62 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
63 return throw_excpt ? AllocateHeap(size, flags, CURRENT_PC)
64 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
65 }
66
67 void Thread::operator delete(void* p) {
68 FreeHeap(p);
69 }
70
71 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
72 // JavaThread
73
74 DEBUG_ONLY(Thread* Thread::_starting_thread = NULL;)
75
76 Thread::Thread():
77 _lock_stack() {
78
79 DEBUG_ONLY(_run_state = PRE_CALL_RUN;)
80
81 // stack and get_thread
82 set_stack_base(NULL);
83 set_stack_size(0);
84 set_lgrp_id(-1);
85 DEBUG_ONLY(clear_suspendible_thread();)
86
87 // allocated data structures
88 set_osthread(NULL);
89 set_resource_area(new (mtThread)ResourceArea());
90 DEBUG_ONLY(_current_resource_mark = NULL;)
91 set_handle_area(new (mtThread) HandleArea(NULL));
92 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, mtClass));
93 set_last_handle_mark(NULL);
94 DEBUG_ONLY(_missed_ic_stub_refill_verifier = NULL);
95
96 // Initial value of zero ==> never claimed.
97 _threads_do_token = 0;
98 _threads_hazard_ptr = NULL;
99 _threads_list_ptr = NULL;
100 _nested_threads_hazard_ptr_cnt = 0;
101 _rcu_counter = 0;
102
103 // the handle mark links itself to last_handle_mark
104 new HandleMark(this);
105
106 // plain initialization
107 debug_only(_owned_locks = NULL;)
108 NOT_PRODUCT(_skip_gcalot = false;)
109 _jvmti_env_iteration_count = 0;
110 set_allocated_bytes(0);
111 _current_pending_raw_monitor = NULL;
112
113 // thread-specific hashCode stream generator state - Marsaglia shift-xor form
114 _hashStateX = os::random();
115 _hashStateY = 842502087;
116 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ;
117 _hashStateW = 273326509;
118
119 // Many of the following fields are effectively final - immutable
120 // Note that nascent threads can't use the Native Monitor-Mutex
121 // construct until the _MutexEvent is initialized ...
122 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
123 // we might instead use a stack of ParkEvents that we could provision on-demand.
124 // The stack would act as a cache to avoid calls to ParkEvent::Allocate()
125 // and ::Release()
126 _ParkEvent = ParkEvent::Allocate(this);
127
128 #ifdef CHECK_UNHANDLED_OOPS
129 if (CheckUnhandledOops) {
130 _unhandled_oops = new UnhandledOops(this);
131 }
132 #endif // CHECK_UNHANDLED_OOPS
133
134 // Notify the barrier set that a thread is being created. The initial
135 // thread is created before the barrier set is available. The call to
136 // BarrierSet::on_thread_create() for this thread is therefore deferred
137 // to BarrierSet::set_barrier_set().
138 BarrierSet* const barrier_set = BarrierSet::barrier_set();
139 if (barrier_set != NULL) {
140 barrier_set->on_thread_create(this);
141 } else {
142 // Only the main thread should be created before the barrier set
143 // and that happens just before Thread::current is set. No other thread
144 // can attach as the VM is not created yet, so they can't execute this code.
145 // If the main thread creates other threads before the barrier set that is an error.
146 assert(Thread::current_or_null() == NULL, "creating thread before barrier set");
147 }
148
149 MACOS_AARCH64_ONLY(DEBUG_ONLY(_wx_init = false));
150 }
151
152 void Thread::initialize_tlab() {
153 if (UseTLAB) {
154 tlab().initialize();
155 }
156 }
157
158 void Thread::initialize_thread_current() {
159 #ifndef USE_LIBRARY_BASED_TLS_ONLY
160 assert(_thr_current == NULL, "Thread::current already initialized");
161 _thr_current = this;
162 #endif
163 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
164 ThreadLocalStorage::set_thread(this);
165 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
166 }
167
168 void Thread::clear_thread_current() {
169 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
170 #ifndef USE_LIBRARY_BASED_TLS_ONLY
171 _thr_current = NULL;
172 #endif
173 ThreadLocalStorage::set_thread(NULL);
174 }
175
176 void Thread::record_stack_base_and_size() {
177 // Note: at this point, Thread object is not yet initialized. Do not rely on
178 // any members being initialized. Do not rely on Thread::current() being set.
179 // If possible, refrain from doing anything which may crash or assert since
180 // quite probably those crash dumps will be useless.
181 set_stack_base(os::current_stack_base());
182 set_stack_size(os::current_stack_size());
183
184 // Set stack limits after thread is initialized.
185 if (is_Java_thread()) {
186 JavaThread::cast(this)->stack_overflow_state()->initialize(stack_base(), stack_end());
187 }
188 }
189
190 void Thread::register_thread_stack_with_NMT() {
191 MemTracker::record_thread_stack(stack_end(), stack_size());
192 }
193
194 void Thread::unregister_thread_stack_with_NMT() {
195 MemTracker::release_thread_stack(stack_end(), stack_size());
196 }
197
198 void Thread::call_run() {
199 DEBUG_ONLY(_run_state = CALL_RUN;)
200
201 // At this point, Thread object should be fully initialized and
202 // Thread::current() should be set.
203
204 assert(Thread::current_or_null() != NULL, "current thread is unset");
205 assert(Thread::current_or_null() == this, "current thread is wrong");
206
207 // Perform common initialization actions
208
209 MACOS_AARCH64_ONLY(this->init_wx());
210
211 register_thread_stack_with_NMT();
212
213 JFR_ONLY(Jfr::on_thread_start(this);)
214
215 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
216 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
217 os::current_thread_id(), p2i(stack_end()),
218 p2i(stack_base()), stack_size()/1024);
219
220 // Perform <ChildClass> initialization actions
221 DEBUG_ONLY(_run_state = PRE_RUN;)
222 this->pre_run();
223
224 // Invoke <ChildClass>::run()
225 DEBUG_ONLY(_run_state = RUN;)
226 this->run();
227 // Returned from <ChildClass>::run(). Thread finished.
228
229 // Perform common tear-down actions
230
231 assert(Thread::current_or_null() != NULL, "current thread is unset");
232 assert(Thread::current_or_null() == this, "current thread is wrong");
233
234 // Perform <ChildClass> tear-down actions
235 DEBUG_ONLY(_run_state = POST_RUN;)
236 this->post_run();
237
238 // Note: at this point the thread object may already have deleted itself,
239 // so from here on do not dereference *this*. Not all thread types currently
240 // delete themselves when they terminate. But no thread should ever be deleted
241 // asynchronously with respect to its termination - that is what _run_state can
242 // be used to check.
243
244 assert(Thread::current_or_null() == NULL, "current thread still present");
245 }
246
247 Thread::~Thread() {
248
249 // Attached threads will remain in PRE_CALL_RUN, as will threads that don't actually
250 // get started due to errors etc. Any active thread should at least reach post_run
251 // before it is deleted (usually in post_run()).
252 assert(_run_state == PRE_CALL_RUN ||
253 _run_state == POST_RUN, "Active Thread deleted before post_run(): "
254 "_run_state=%d", (int)_run_state);
255
256 // Notify the barrier set that a thread is being destroyed. Note that a barrier
257 // set might not be available if we encountered errors during bootstrapping.
258 BarrierSet* const barrier_set = BarrierSet::barrier_set();
259 if (barrier_set != NULL) {
260 barrier_set->on_thread_destroy(this);
261 }
262
263 // deallocate data structures
264 delete resource_area();
265 // since the handle marks are using the handle area, we have to deallocated the root
266 // handle mark before deallocating the thread's handle area,
267 assert(last_handle_mark() != NULL, "check we have an element");
268 delete last_handle_mark();
269 assert(last_handle_mark() == NULL, "check we have reached the end");
270
271 ParkEvent::Release(_ParkEvent);
272 // Set to NULL as a termination indicator for has_terminated().
273 Atomic::store(&_ParkEvent, (ParkEvent*)NULL);
274
275 delete handle_area();
276 delete metadata_handles();
277
278 // osthread() can be NULL, if creation of thread failed.
279 if (osthread() != NULL) os::free_thread(osthread());
280
281 // Clear Thread::current if thread is deleting itself and it has not
282 // already been done. This must be done before the memory is deallocated.
283 // Needed to ensure JNI correctly detects non-attached threads.
284 if (this == Thread::current_or_null()) {
285 Thread::clear_thread_current();
286 }
287
288 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
289 }
290
291 #ifdef ASSERT
292 // A JavaThread is considered dangling if it not handshake-safe with respect to
293 // the current thread, it is not on a ThreadsList, or not at safepoint.
294 void Thread::check_for_dangling_thread_pointer(Thread *thread) {
295 assert(!thread->is_Java_thread() ||
296 JavaThread::cast(thread)->is_handshake_safe_for(Thread::current()) ||
297 !JavaThread::cast(thread)->on_thread_list() ||
298 SafepointSynchronize::is_at_safepoint() ||
299 ThreadsSMRSupport::is_a_protected_JavaThread_with_lock(JavaThread::cast(thread)),
300 "possibility of dangling Thread pointer");
301 }
302 #endif
303
304 // Is the target JavaThread protected by the calling Thread or by some other
305 // mechanism?
306 //
307 bool Thread::is_JavaThread_protected(const JavaThread* target) {
308 Thread* current_thread = Thread::current();
309
310 // Do the simplest check first:
311 if (SafepointSynchronize::is_at_safepoint()) {
312 // The target is protected since JavaThreads cannot exit
313 // while we're at a safepoint.
314 return true;
315 }
316
317 // If the target hasn't been started yet then it is trivially
318 // "protected". We assume the caller is the thread that will do
319 // the starting.
320 if (target->osthread() == NULL || target->osthread()->get_state() <= INITIALIZED) {
321 return true;
322 }
323
324 // Now make the simple checks based on who the caller is:
325 if (current_thread == target || Threads_lock->owner() == current_thread) {
326 // Target JavaThread is self or calling thread owns the Threads_lock.
327 // Second check is the same as Threads_lock->owner_is_self(),
328 // but we already have the current thread so check directly.
329 return true;
330 }
331
332 // Check the ThreadsLists associated with the calling thread (if any)
333 // to see if one of them protects the target JavaThread:
334 if (is_JavaThread_protected_by_TLH(target)) {
335 return true;
336 }
337
338 // Use this debug code with -XX:+UseNewCode to diagnose locations that
339 // are missing a ThreadsListHandle or other protection mechanism:
340 // guarantee(!UseNewCode, "current_thread=" INTPTR_FORMAT " is not protecting target="
341 // INTPTR_FORMAT, p2i(current_thread), p2i(target));
342
343 // Note: Since 'target' isn't protected by a TLH, the call to
344 // target->is_handshake_safe_for() may crash, but we have debug bits so
345 // we'll be able to figure out what protection mechanism is missing.
346 assert(target->is_handshake_safe_for(current_thread), "JavaThread=" INTPTR_FORMAT
347 " is not protected and not handshake safe.", p2i(target));
348
349 // The target JavaThread is not protected so it is not safe to query:
350 return false;
351 }
352
353 // Is the target JavaThread protected by a ThreadsListHandle (TLH) associated
354 // with the calling Thread?
355 //
356 bool Thread::is_JavaThread_protected_by_TLH(const JavaThread* target) {
357 Thread* current_thread = Thread::current();
358
359 // Check the ThreadsLists associated with the calling thread (if any)
360 // to see if one of them protects the target JavaThread:
361 for (SafeThreadsListPtr* stlp = current_thread->_threads_list_ptr;
362 stlp != NULL; stlp = stlp->previous()) {
363 if (stlp->list()->includes(target)) {
364 // The target JavaThread is protected by this ThreadsList:
365 return true;
366 }
367 }
368
369 // The target JavaThread is not protected by a TLH so it is not safe to query:
370 return false;
371 }
372
373 ThreadPriority Thread::get_priority(const Thread* const thread) {
374 ThreadPriority priority;
375 // Can return an error!
376 (void)os::get_priority(thread, priority);
377 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
378 return priority;
379 }
380
381 void Thread::set_priority(Thread* thread, ThreadPriority priority) {
382 debug_only(check_for_dangling_thread_pointer(thread);)
383 // Can return an error!
384 (void)os::set_priority(thread, priority);
385 }
386
387
388 void Thread::start(Thread* thread) {
389 // Start is different from resume in that its safety is guaranteed by context or
390 // being called from a Java method synchronized on the Thread object.
391 if (thread->is_Java_thread()) {
392 // Initialize the thread state to RUNNABLE before starting this thread.
393 // Can not set it after the thread started because we do not know the
394 // exact thread state at that time. It could be in MONITOR_WAIT or
395 // in SLEEPING or some other state.
396 java_lang_Thread::set_thread_status(JavaThread::cast(thread)->threadObj(),
397 JavaThreadStatus::RUNNABLE);
398 }
399 os::start_thread(thread);
400 }
401
402 // GC Support
403 bool Thread::claim_par_threads_do(uintx claim_token) {
404 uintx token = _threads_do_token;
405 if (token != claim_token) {
406 uintx res = Atomic::cmpxchg(&_threads_do_token, token, claim_token);
407 if (res == token) {
408 return true;
409 }
410 guarantee(res == claim_token, "invariant");
411 }
412 return false;
413 }
414
415 void Thread::oops_do_no_frames(OopClosure* f, CodeBlobClosure* cf) {
416 // Do oop for ThreadShadow
417 f->do_oop((oop*)&_pending_exception);
418 handle_area()->oops_do(f);
419 if (!UseHeavyMonitors) {
420 lock_stack().oops_do(f);
421 }
422 }
423
424 // If the caller is a NamedThread, then remember, in the current scope,
425 // the given JavaThread in its _processed_thread field.
426 class RememberProcessedThread: public StackObj {
427 NamedThread* _cur_thr;
428 public:
429 RememberProcessedThread(Thread* thread) {
430 Thread* self = Thread::current();
431 if (self->is_Named_thread()) {
432 _cur_thr = (NamedThread *)self;
433 assert(_cur_thr->processed_thread() == NULL, "nesting not supported");
434 _cur_thr->set_processed_thread(thread);
435 } else {
436 _cur_thr = NULL;
437 }
438 }
439
440 ~RememberProcessedThread() {
441 if (_cur_thr) {
442 assert(_cur_thr->processed_thread() != NULL, "nesting not supported");
443 _cur_thr->set_processed_thread(NULL);
444 }
445 }
446 };
447
448 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
449 // Record JavaThread to GC thread
450 RememberProcessedThread rpt(this);
451 oops_do_no_frames(f, cf);
452 oops_do_frames(f, cf);
453 }
454
455 void Thread::metadata_handles_do(void f(Metadata*)) {
456 // Only walk the Handles in Thread.
457 if (metadata_handles() != NULL) {
458 for (int i = 0; i< metadata_handles()->length(); i++) {
459 f(metadata_handles()->at(i));
460 }
461 }
462 }
463
464 void Thread::print_on(outputStream* st, bool print_extended_info) const {
465 // get_priority assumes osthread initialized
466 if (osthread() != NULL) {
467 int os_prio;
468 if (os::get_native_priority(this, &os_prio) == OS_OK) {
469 st->print("os_prio=%d ", os_prio);
470 }
471
472 st->print("cpu=%.2fms ",
473 os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0
474 );
475 st->print("elapsed=%.2fs ",
476 _statistical_info.getElapsedTime() / 1000.0
477 );
478 if (is_Java_thread() && (PrintExtendedThreadInfo || print_extended_info)) {
479 size_t allocated_bytes = (size_t) const_cast<Thread*>(this)->cooked_allocated_bytes();
480 st->print("allocated=" SIZE_FORMAT "%s ",
481 byte_size_in_proper_unit(allocated_bytes),
482 proper_unit_for_byte_size(allocated_bytes)
483 );
484 st->print("defined_classes=" INT64_FORMAT " ", _statistical_info.getDefineClassCount());
485 }
486
487 st->print("tid=" INTPTR_FORMAT " ", p2i(this));
488 if (!is_Java_thread() || !JavaThread::cast(this)->is_vthread_mounted()) {
489 osthread()->print_on(st);
490 }
491 }
492 ThreadsSMRSupport::print_info_on(this, st);
493 st->print(" ");
494 debug_only(if (WizardMode) print_owned_locks_on(st);)
495 }
496
497 void Thread::print() const { print_on(tty); }
498
499 // Thread::print_on_error() is called by fatal error handler. Don't use
500 // any lock or allocate memory.
501 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
502 assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
503
504 st->print("%s \"%s\"", type_name(), name());
505
506 OSThread* os_thr = osthread();
507 if (os_thr != NULL) {
508 if (os_thr->get_state() != ZOMBIE) {
509 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
510 p2i(stack_end()), p2i(stack_base()));
511 st->print(" [id=%d]", osthread()->thread_id());
512 } else {
513 st->print(" terminated");
514 }
515 } else {
516 st->print(" unknown state (no osThread)");
517 }
518 ThreadsSMRSupport::print_info_on(this, st);
519 }
520
521 void Thread::print_value_on(outputStream* st) const {
522 if (is_Named_thread()) {
523 st->print(" \"%s\" ", name());
524 }
525 st->print(INTPTR_FORMAT, p2i(this)); // print address
526 }
527
528 #ifdef ASSERT
529 void Thread::print_owned_locks_on(outputStream* st) const {
530 Mutex* cur = _owned_locks;
531 if (cur == NULL) {
532 st->print(" (no locks) ");
533 } else {
534 st->print_cr(" Locks owned:");
535 while (cur) {
536 cur->print_on(st);
537 cur = cur->next();
538 }
539 }
540 }
541 #endif // ASSERT
542
543 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
544 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
545 // used for compilation in the future. If that change is made, the need for these methods
546 // should be revisited, and they should be removed if possible.
547
548 bool Thread::is_lock_owned(address adr) const {
549 assert(adr != ANONYMOUS_OWNER, "must convert to lock object");
550 return !UseHeavyMonitors && lock_stack().contains(cast_to_oop(adr));
551 }
552
553 bool Thread::set_as_starting_thread() {
554 assert(_starting_thread == NULL, "already initialized: "
555 "_starting_thread=" INTPTR_FORMAT, p2i(_starting_thread));
556 // NOTE: this must be called inside the main thread.
557 DEBUG_ONLY(_starting_thread = this;)
558 return os::create_main_thread(JavaThread::cast(this));
559 }
560
561 // Ad-hoc mutual exclusion primitives: SpinLock
562 //
563 // We employ SpinLocks _only for low-contention, fixed-length
564 // short-duration critical sections where we're concerned
565 // about native mutex_t or HotSpot Mutex:: latency.
566 //
567 // TODO-FIXME: ListLock should be of type SpinLock.
568 // We should make this a 1st-class type, integrated into the lock
569 // hierarchy as leaf-locks. Critically, the SpinLock structure
570 // should have sufficient padding to avoid false-sharing and excessive
571 // cache-coherency traffic.
572
573
574 typedef volatile int SpinLockT;
575
576 void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
577 if (Atomic::cmpxchg(adr, 0, 1) == 0) {
578 return; // normal fast-path return
579 }
580
581 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
582 int ctr = 0;
583 int Yields = 0;
584 for (;;) {
585 while (*adr != 0) {
586 ++ctr;
587 if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
588 if (Yields > 5) {
589 os::naked_short_sleep(1);
590 } else {
591 os::naked_yield();
592 ++Yields;
593 }
594 } else {
595 SpinPause();
596 }
597 }
598 if (Atomic::cmpxchg(adr, 0, 1) == 0) return;
599 }
600 }
601
602 void Thread::SpinRelease(volatile int * adr) {
603 assert(*adr != 0, "invariant");
604 OrderAccess::fence(); // guarantee at least release consistency.
605 // Roach-motel semantics.
606 // It's safe if subsequent LDs and STs float "up" into the critical section,
607 // but prior LDs and STs within the critical section can't be allowed
608 // to reorder or float past the ST that releases the lock.
609 // Loads and stores in the critical section - which appear in program
610 // order before the store that releases the lock - must also appear
611 // before the store that releases the lock in memory visibility order.
612 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before
613 // the ST of 0 into the lock-word which releases the lock, so fence
614 // more than covers this on all platforms.
615 *adr = 0;
616 }