/* * Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #include "precompiled.hpp" #include "classfile/systemDictionary.hpp" #include "memory/allocation.hpp" #include "memory/heapInspection.hpp" #include "memory/oopFactory.hpp" #include "memory/resourceArea.hpp" #include "oops/instanceKlass.hpp" #include "oops/objArrayOop.inline.hpp" #include "oops/oop.inline.hpp" #include "runtime/atomic.hpp" #include "runtime/handles.inline.hpp" #include "runtime/init.hpp" #include "runtime/thread.inline.hpp" #include "runtime/threadSMR.inline.hpp" #include "runtime/vframe.hpp" #include "runtime/vmThread.hpp" #include "runtime/vm_operations.hpp" #include "services/threadService.hpp" // TODO: we need to define a naming convention for perf counters // to distinguish counters for: // - standard JSR174 use // - Hotspot extension (public and committed) // - Hotspot extension (private/internal and uncommitted) // Default is disabled. bool ThreadService::_thread_monitoring_contention_enabled = false; bool ThreadService::_thread_cpu_time_enabled = false; bool ThreadService::_thread_allocated_memory_enabled = false; PerfCounter* ThreadService::_total_threads_count = NULL; PerfVariable* ThreadService::_live_threads_count = NULL; PerfVariable* ThreadService::_peak_threads_count = NULL; PerfVariable* ThreadService::_daemon_threads_count = NULL; volatile int ThreadService::_exiting_threads_count = 0; volatile int ThreadService::_exiting_daemon_threads_count = 0; ThreadDumpResult* ThreadService::_threaddump_list = NULL; static const int INITIAL_ARRAY_SIZE = 10; void ThreadService::init() { EXCEPTION_MARK; // These counters are for java.lang.management API support. // They are created even if -XX:-UsePerfData is set and in // that case, they will be allocated on C heap. _total_threads_count = PerfDataManager::create_counter(JAVA_THREADS, "started", PerfData::U_Events, CHECK); _live_threads_count = PerfDataManager::create_variable(JAVA_THREADS, "live", PerfData::U_None, CHECK); _peak_threads_count = PerfDataManager::create_variable(JAVA_THREADS, "livePeak", PerfData::U_None, CHECK); _daemon_threads_count = PerfDataManager::create_variable(JAVA_THREADS, "daemon", PerfData::U_None, CHECK); if (os::is_thread_cpu_time_supported()) { _thread_cpu_time_enabled = true; } _thread_allocated_memory_enabled = true; // Always on, so enable it } void ThreadService::reset_peak_thread_count() { // Acquire the lock to update the peak thread count // to synchronize with thread addition and removal. MutexLockerEx mu(Threads_lock); _peak_threads_count->set_value(get_live_thread_count()); } void ThreadService::add_thread(JavaThread* thread, bool daemon) { // Do not count VM internal or JVMTI agent threads if (thread->is_hidden_from_external_view() || thread->is_jvmti_agent_thread()) { return; } _total_threads_count->inc(); _live_threads_count->inc(); if (_live_threads_count->get_value() > _peak_threads_count->get_value()) { _peak_threads_count->set_value(_live_threads_count->get_value()); } if (daemon) { _daemon_threads_count->inc(); } } void ThreadService::remove_thread(JavaThread* thread, bool daemon) { Atomic::dec((jint*) &_exiting_threads_count); if (thread->is_hidden_from_external_view() || thread->is_jvmti_agent_thread()) { return; } _live_threads_count->set_value(_live_threads_count->get_value() - 1); if (daemon) { _daemon_threads_count->set_value(_daemon_threads_count->get_value() - 1); Atomic::dec((jint*) &_exiting_daemon_threads_count); } } void ThreadService::current_thread_exiting(JavaThread* jt) { assert(jt == JavaThread::current(), "Called by current thread"); Atomic::inc((jint*) &_exiting_threads_count); oop threadObj = jt->threadObj(); if (threadObj != NULL && java_lang_Thread::is_daemon(threadObj)) { Atomic::inc((jint*) &_exiting_daemon_threads_count); } } // FIXME: JVMTI should call this function Handle ThreadService::get_current_contended_monitor(JavaThread* thread) { assert(thread != NULL, "should be non-NULL"); debug_only(Thread::check_for_dangling_thread_pointer(thread);) ObjectMonitor *wait_obj = thread->current_waiting_monitor(); oop obj = NULL; if (wait_obj != NULL) { // thread is doing an Object.wait() call obj = (oop) wait_obj->object(); assert(obj != NULL, "Object.wait() should have an object"); } else { ObjectMonitor *enter_obj = thread->current_pending_monitor(); if (enter_obj != NULL) { // thread is trying to enter() or raw_enter() an ObjectMonitor. obj = (oop) enter_obj->object(); } // If obj == NULL, then ObjectMonitor is raw which doesn't count. } Handle h(Thread::current(), obj); return h; } bool ThreadService::set_thread_monitoring_contention(bool flag) { MutexLocker m(Management_lock); bool prev = _thread_monitoring_contention_enabled; _thread_monitoring_contention_enabled = flag; return prev; } bool ThreadService::set_thread_cpu_time_enabled(bool flag) { MutexLocker m(Management_lock); bool prev = _thread_cpu_time_enabled; _thread_cpu_time_enabled = flag; return prev; } bool ThreadService::set_thread_allocated_memory_enabled(bool flag) { MutexLocker m(Management_lock); bool prev = _thread_allocated_memory_enabled; _thread_allocated_memory_enabled = flag; return prev; } // GC support void ThreadService::oops_do(OopClosure* f) { for (ThreadDumpResult* dump = _threaddump_list; dump != NULL; dump = dump->next()) { dump->oops_do(f); } } void ThreadService::metadata_do(void f(Metadata*)) { for (ThreadDumpResult* dump = _threaddump_list; dump != NULL; dump = dump->next()) { dump->metadata_do(f); } } void ThreadService::add_thread_dump(ThreadDumpResult* dump) { MutexLocker ml(Management_lock); if (_threaddump_list == NULL) { _threaddump_list = dump; } else { dump->set_next(_threaddump_list); _threaddump_list = dump; } } void ThreadService::remove_thread_dump(ThreadDumpResult* dump) { MutexLocker ml(Management_lock); ThreadDumpResult* prev = NULL; bool found = false; for (ThreadDumpResult* d = _threaddump_list; d != NULL; prev = d, d = d->next()) { if (d == dump) { if (prev == NULL) { _threaddump_list = dump->next(); } else { prev->set_next(dump->next()); } found = true; break; } } assert(found, "The threaddump result to be removed must exist."); } // Dump stack trace of threads specified in the given threads array. // Returns StackTraceElement[][] each element is the stack trace of a thread in // the corresponding entry in the given threads array Handle ThreadService::dump_stack_traces(GrowableArray* threads, int num_threads, TRAPS) { assert(num_threads > 0, "just checking"); ThreadDumpResult dump_result; VM_ThreadDump op(&dump_result, threads, num_threads, -1, /* entire stack */ false, /* with locked monitors */ false /* with locked synchronizers */); VMThread::execute(&op); // Allocate the resulting StackTraceElement[][] object ResourceMark rm(THREAD); Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_StackTraceElement_array(), true, CHECK_NH); ObjArrayKlass* ik = ObjArrayKlass::cast(k); objArrayOop r = oopFactory::new_objArray(ik, num_threads, CHECK_NH); objArrayHandle result_obj(THREAD, r); int num_snapshots = dump_result.num_snapshots(); assert(num_snapshots == num_threads, "Must have num_threads thread snapshots"); assert(num_snapshots == 0 || dump_result.t_list_has_been_set(), "ThreadsList must have been set if we have a snapshot"); int i = 0; for (ThreadSnapshot* ts = dump_result.snapshots(); ts != NULL; i++, ts = ts->next()) { ThreadStackTrace* stacktrace = ts->get_stack_trace(); if (stacktrace == NULL) { // No stack trace result_obj->obj_at_put(i, NULL); } else { // Construct an array of java/lang/StackTraceElement object Handle backtrace_h = stacktrace->allocate_fill_stack_trace_element_array(CHECK_NH); result_obj->obj_at_put(i, backtrace_h()); } } return result_obj; } void ThreadService::reset_contention_count_stat(JavaThread* thread) { ThreadStatistics* stat = thread->get_thread_stat(); if (stat != NULL) { stat->reset_count_stat(); } } void ThreadService::reset_contention_time_stat(JavaThread* thread) { ThreadStatistics* stat = thread->get_thread_stat(); if (stat != NULL) { stat->reset_time_stat(); } } // Find deadlocks involving object monitors and concurrent locks if concurrent_locks is true DeadlockCycle* ThreadService::find_deadlocks_at_safepoint(ThreadsList * t_list, bool concurrent_locks) { assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); // This code was modified from the original Threads::find_deadlocks code. int globalDfn = 0, thisDfn; ObjectMonitor* waitingToLockMonitor = NULL; oop waitingToLockBlocker = NULL; bool blocked_on_monitor = false; JavaThread *currentThread, *previousThread; int num_deadlocks = 0; // Initialize the depth-first-number for each JavaThread. JavaThreadIterator jti(t_list); for (JavaThread* jt = jti.first(); jt != NULL; jt = jti.next()) { jt->set_depth_first_number(-1); } DeadlockCycle* deadlocks = NULL; DeadlockCycle* last = NULL; DeadlockCycle* cycle = new DeadlockCycle(); for (JavaThread* jt = jti.first(); jt != NULL; jt = jti.next()) { if (jt->depth_first_number() >= 0) { // this thread was already visited continue; } thisDfn = globalDfn; jt->set_depth_first_number(globalDfn++); previousThread = jt; currentThread = jt; cycle->reset(); // When there is a deadlock, all the monitors involved in the dependency // cycle must be contended and heavyweight. So we only care about the // heavyweight monitor a thread is waiting to lock. waitingToLockMonitor = (ObjectMonitor*)jt->current_pending_monitor(); if (concurrent_locks) { waitingToLockBlocker = jt->current_park_blocker(); } while (waitingToLockMonitor != NULL || waitingToLockBlocker != NULL) { cycle->add_thread(currentThread); if (waitingToLockMonitor != NULL) { address currentOwner = (address)waitingToLockMonitor->owner(); if (currentOwner != NULL) { currentThread = Threads::owning_thread_from_monitor_owner(t_list, currentOwner); if (currentThread == NULL) { // This function is called at a safepoint so the JavaThread // that owns waitingToLockMonitor should be findable, but // if it is not findable, then the previous currentThread is // blocked permanently. We record this as a deadlock. num_deadlocks++; cycle->set_deadlock(true); // add this cycle to the deadlocks list if (deadlocks == NULL) { deadlocks = cycle; } else { last->set_next(cycle); } last = cycle; cycle = new DeadlockCycle(); break; } } } else { if (concurrent_locks) { if (waitingToLockBlocker->is_a(SystemDictionary::abstract_ownable_synchronizer_klass())) { oop threadObj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(waitingToLockBlocker); // This JavaThread (if there is one) is protected by the // ThreadsListSetter in VM_FindDeadlocks::doit(). currentThread = threadObj != NULL ? java_lang_Thread::thread(threadObj) : NULL; } else { currentThread = NULL; } } } if (currentThread == NULL) { // No dependency on another thread break; } if (currentThread->depth_first_number() < 0) { // First visit to this thread currentThread->set_depth_first_number(globalDfn++); } else if (currentThread->depth_first_number() < thisDfn) { // Thread already visited, and not on a (new) cycle break; } else if (currentThread == previousThread) { // Self-loop, ignore break; } else { // We have a (new) cycle num_deadlocks++; cycle->set_deadlock(true); // add this cycle to the deadlocks list if (deadlocks == NULL) { deadlocks = cycle; } else { last->set_next(cycle); } last = cycle; cycle = new DeadlockCycle(); break; } previousThread = currentThread; waitingToLockMonitor = (ObjectMonitor*)currentThread->current_pending_monitor(); if (concurrent_locks) { waitingToLockBlocker = currentThread->current_park_blocker(); } } } delete cycle; return deadlocks; } ThreadDumpResult::ThreadDumpResult() : _num_threads(0), _num_snapshots(0), _snapshots(NULL), _next(NULL), _last(NULL), _setter() { // Create a new ThreadDumpResult object and append to the list. // If GC happens before this function returns, Method* // in the stack trace will be visited. ThreadService::add_thread_dump(this); } ThreadDumpResult::ThreadDumpResult(int num_threads) : _num_threads(num_threads), _num_snapshots(0), _snapshots(NULL), _next(NULL), _last(NULL), _setter() { // Create a new ThreadDumpResult object and append to the list. // If GC happens before this function returns, oops // will be visited. ThreadService::add_thread_dump(this); } ThreadDumpResult::~ThreadDumpResult() { ThreadService::remove_thread_dump(this); // free all the ThreadSnapshot objects created during // the VM_ThreadDump operation ThreadSnapshot* ts = _snapshots; while (ts != NULL) { ThreadSnapshot* p = ts; ts = ts->next(); delete p; } } void ThreadDumpResult::add_thread_snapshot(ThreadSnapshot* ts) { assert(_num_threads == 0 || _num_snapshots < _num_threads, "_num_snapshots must be less than _num_threads"); _num_snapshots++; if (_snapshots == NULL) { _snapshots = ts; } else { _last->set_next(ts); } _last = ts; } void ThreadDumpResult::oops_do(OopClosure* f) { for (ThreadSnapshot* ts = _snapshots; ts != NULL; ts = ts->next()) { ts->oops_do(f); } } void ThreadDumpResult::metadata_do(void f(Metadata*)) { for (ThreadSnapshot* ts = _snapshots; ts != NULL; ts = ts->next()) { ts->metadata_do(f); } } ThreadsList* ThreadDumpResult::t_list() { return _setter.list(); } StackFrameInfo::StackFrameInfo(javaVFrame* jvf, bool with_lock_info) { _method = jvf->method(); _bci = jvf->bci(); _class_holder = _method->method_holder()->klass_holder(); _locked_monitors = NULL; if (with_lock_info) { ResourceMark rm; GrowableArray* list = jvf->locked_monitors(); int length = list->length(); if (length > 0) { _locked_monitors = new (ResourceObj::C_HEAP, mtInternal) GrowableArray(length, true); for (int i = 0; i < length; i++) { MonitorInfo* monitor = list->at(i); assert(monitor->owner(), "This monitor must have an owning object"); _locked_monitors->append(monitor->owner()); } } } } void StackFrameInfo::oops_do(OopClosure* f) { if (_locked_monitors != NULL) { int length = _locked_monitors->length(); for (int i = 0; i < length; i++) { f->do_oop((oop*) _locked_monitors->adr_at(i)); } } f->do_oop(&_class_holder); } void StackFrameInfo::metadata_do(void f(Metadata*)) { f(_method); } void StackFrameInfo::print_on(outputStream* st) const { ResourceMark rm; java_lang_Throwable::print_stack_element(st, method(), bci()); int len = (_locked_monitors != NULL ? _locked_monitors->length() : 0); for (int i = 0; i < len; i++) { oop o = _locked_monitors->at(i); st->print_cr("\t- locked <" INTPTR_FORMAT "> (a %s)", p2i(o), o->klass()->external_name()); } } // Iterate through monitor cache to find JNI locked monitors class InflatedMonitorsClosure: public MonitorClosure { private: ThreadStackTrace* _stack_trace; Thread* _thread; public: InflatedMonitorsClosure(Thread* t, ThreadStackTrace* st) { _thread = t; _stack_trace = st; } void do_monitor(ObjectMonitor* mid) { if (mid->owner() == _thread) { oop object = (oop) mid->object(); if (!_stack_trace->is_owned_monitor_on_stack(object)) { _stack_trace->add_jni_locked_monitor(object); } } } }; ThreadStackTrace::ThreadStackTrace(JavaThread* t, bool with_locked_monitors) { _thread = t; _frames = new (ResourceObj::C_HEAP, mtInternal) GrowableArray(INITIAL_ARRAY_SIZE, true); _depth = 0; _with_locked_monitors = with_locked_monitors; if (_with_locked_monitors) { _jni_locked_monitors = new (ResourceObj::C_HEAP, mtInternal) GrowableArray(INITIAL_ARRAY_SIZE, true); } else { _jni_locked_monitors = NULL; } } ThreadStackTrace::~ThreadStackTrace() { for (int i = 0; i < _frames->length(); i++) { delete _frames->at(i); } delete _frames; if (_jni_locked_monitors != NULL) { delete _jni_locked_monitors; } } void ThreadStackTrace::dump_stack_at_safepoint(int maxDepth) { assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); if (_thread->has_last_Java_frame()) { RegisterMap reg_map(_thread); vframe* start_vf = _thread->last_java_vframe(®_map); int count = 0; for (vframe* f = start_vf; f; f = f->sender() ) { if (maxDepth >= 0 && count == maxDepth) { // Skip frames if more than maxDepth break; } if (f->is_java_frame()) { javaVFrame* jvf = javaVFrame::cast(f); add_stack_frame(jvf); count++; } else { // Ignore non-Java frames } } } if (_with_locked_monitors) { // Iterate inflated monitors and find monitors locked by this thread // not found in the stack InflatedMonitorsClosure imc(_thread, this); ObjectSynchronizer::monitors_iterate(&imc); } } bool ThreadStackTrace::is_owned_monitor_on_stack(oop object) { assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); bool found = false; int num_frames = get_stack_depth(); for (int depth = 0; depth < num_frames; depth++) { StackFrameInfo* frame = stack_frame_at(depth); int len = frame->num_locked_monitors(); GrowableArray* locked_monitors = frame->locked_monitors(); for (int j = 0; j < len; j++) { oop monitor = locked_monitors->at(j); assert(monitor != NULL, "must be a Java object"); if (monitor == object) { found = true; break; } } } return found; } Handle ThreadStackTrace::allocate_fill_stack_trace_element_array(TRAPS) { InstanceKlass* ik = SystemDictionary::StackTraceElement_klass(); assert(ik != NULL, "must be loaded in 1.4+"); // Allocate an array of java/lang/StackTraceElement object objArrayOop ste = oopFactory::new_objArray(ik, _depth, CHECK_NH); objArrayHandle backtrace(THREAD, ste); for (int j = 0; j < _depth; j++) { StackFrameInfo* frame = _frames->at(j); methodHandle mh(THREAD, frame->method()); oop element = java_lang_StackTraceElement::create(mh, frame->bci(), CHECK_NH); backtrace->obj_at_put(j, element); } return backtrace; } void ThreadStackTrace::add_stack_frame(javaVFrame* jvf) { StackFrameInfo* frame = new StackFrameInfo(jvf, _with_locked_monitors); _frames->append(frame); _depth++; } void ThreadStackTrace::oops_do(OopClosure* f) { int length = _frames->length(); for (int i = 0; i < length; i++) { _frames->at(i)->oops_do(f); } length = (_jni_locked_monitors != NULL ? _jni_locked_monitors->length() : 0); for (int j = 0; j < length; j++) { f->do_oop((oop*) _jni_locked_monitors->adr_at(j)); } } void ThreadStackTrace::metadata_do(void f(Metadata*)) { int length = _frames->length(); for (int i = 0; i < length; i++) { _frames->at(i)->metadata_do(f); } } ConcurrentLocksDump::~ConcurrentLocksDump() { if (_retain_map_on_free) { return; } for (ThreadConcurrentLocks* t = _map; t != NULL;) { ThreadConcurrentLocks* tcl = t; t = t->next(); delete tcl; } } void ConcurrentLocksDump::dump_at_safepoint() { // dump all locked concurrent locks assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); ResourceMark rm; GrowableArray* aos_objects = new GrowableArray(INITIAL_ARRAY_SIZE); // Find all instances of AbstractOwnableSynchronizer HeapInspection::find_instances_at_safepoint(SystemDictionary::abstract_ownable_synchronizer_klass(), aos_objects); // Build a map of thread to its owned AQS locks build_map(aos_objects); } // build a map of JavaThread to all its owned AbstractOwnableSynchronizer void ConcurrentLocksDump::build_map(GrowableArray* aos_objects) { int length = aos_objects->length(); for (int i = 0; i < length; i++) { oop o = aos_objects->at(i); oop owner_thread_obj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(o); if (owner_thread_obj != NULL) { // See comments in ThreadConcurrentLocks to see how this // JavaThread* is protected. JavaThread* thread = java_lang_Thread::thread(owner_thread_obj); assert(o->is_instance(), "Must be an instanceOop"); add_lock(thread, (instanceOop) o); } } } void ConcurrentLocksDump::add_lock(JavaThread* thread, instanceOop o) { ThreadConcurrentLocks* tcl = thread_concurrent_locks(thread); if (tcl != NULL) { tcl->add_lock(o); return; } // First owned lock found for this thread tcl = new ThreadConcurrentLocks(thread); tcl->add_lock(o); if (_map == NULL) { _map = tcl; } else { _last->set_next(tcl); } _last = tcl; } ThreadConcurrentLocks* ConcurrentLocksDump::thread_concurrent_locks(JavaThread* thread) { for (ThreadConcurrentLocks* tcl = _map; tcl != NULL; tcl = tcl->next()) { if (tcl->java_thread() == thread) { return tcl; } } return NULL; } void ConcurrentLocksDump::print_locks_on(JavaThread* t, outputStream* st) { st->print_cr(" Locked ownable synchronizers:"); ThreadConcurrentLocks* tcl = thread_concurrent_locks(t); GrowableArray* locks = (tcl != NULL ? tcl->owned_locks() : NULL); if (locks == NULL || locks->is_empty()) { st->print_cr("\t- None"); st->cr(); return; } for (int i = 0; i < locks->length(); i++) { instanceOop obj = locks->at(i); st->print_cr("\t- <" INTPTR_FORMAT "> (a %s)", p2i(obj), obj->klass()->external_name()); } st->cr(); } ThreadConcurrentLocks::ThreadConcurrentLocks(JavaThread* thread) { _thread = thread; _owned_locks = new (ResourceObj::C_HEAP, mtInternal) GrowableArray(INITIAL_ARRAY_SIZE, true); _next = NULL; } ThreadConcurrentLocks::~ThreadConcurrentLocks() { delete _owned_locks; } void ThreadConcurrentLocks::add_lock(instanceOop o) { _owned_locks->append(o); } void ThreadConcurrentLocks::oops_do(OopClosure* f) { int length = _owned_locks->length(); for (int i = 0; i < length; i++) { f->do_oop((oop*) _owned_locks->adr_at(i)); } } ThreadStatistics::ThreadStatistics() { _contended_enter_count = 0; _monitor_wait_count = 0; _sleep_count = 0; _count_pending_reset = false; _timer_pending_reset = false; memset((void*) _perf_recursion_counts, 0, sizeof(_perf_recursion_counts)); } ThreadSnapshot::ThreadSnapshot(ThreadsList * t_list, JavaThread* thread) { _thread = thread; _threadObj = thread->threadObj(); _stack_trace = NULL; _concurrent_locks = NULL; _next = NULL; ThreadStatistics* stat = thread->get_thread_stat(); _contended_enter_ticks = stat->contended_enter_ticks(); _contended_enter_count = stat->contended_enter_count(); _monitor_wait_ticks = stat->monitor_wait_ticks(); _monitor_wait_count = stat->monitor_wait_count(); _sleep_ticks = stat->sleep_ticks(); _sleep_count = stat->sleep_count(); _blocker_object = NULL; _blocker_object_owner = NULL; _thread_status = java_lang_Thread::get_thread_status(_threadObj); _is_ext_suspended = thread->is_being_ext_suspended(); _is_in_native = (thread->thread_state() == _thread_in_native); if (_thread_status == java_lang_Thread::BLOCKED_ON_MONITOR_ENTER || _thread_status == java_lang_Thread::IN_OBJECT_WAIT || _thread_status == java_lang_Thread::IN_OBJECT_WAIT_TIMED) { Handle obj = ThreadService::get_current_contended_monitor(thread); if (obj() == NULL) { // monitor no longer exists; thread is not blocked _thread_status = java_lang_Thread::RUNNABLE; } else { _blocker_object = obj(); JavaThread* owner = ObjectSynchronizer::get_lock_owner(t_list, obj); if ((owner == NULL && _thread_status == java_lang_Thread::BLOCKED_ON_MONITOR_ENTER) || (owner != NULL && owner->is_attaching_via_jni())) { // ownership information of the monitor is not available // (may no longer be owned or releasing to some other thread) // make this thread in RUNNABLE state. // And when the owner thread is in attaching state, the java thread // is not completely initialized. For example thread name and id // and may not be set, so hide the attaching thread. _thread_status = java_lang_Thread::RUNNABLE; _blocker_object = NULL; } else if (owner != NULL) { _blocker_object_owner = owner->threadObj(); } } } // Support for JSR-166 locks if (JDK_Version::current().supports_thread_park_blocker() && (_thread_status == java_lang_Thread::PARKED || _thread_status == java_lang_Thread::PARKED_TIMED)) { _blocker_object = thread->current_park_blocker(); if (_blocker_object != NULL && _blocker_object->is_a(SystemDictionary::abstract_ownable_synchronizer_klass())) { _blocker_object_owner = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(_blocker_object); } } } ThreadSnapshot::~ThreadSnapshot() { delete _stack_trace; delete _concurrent_locks; } void ThreadSnapshot::dump_stack_at_safepoint(int max_depth, bool with_locked_monitors) { _stack_trace = new ThreadStackTrace(_thread, with_locked_monitors); _stack_trace->dump_stack_at_safepoint(max_depth); } void ThreadSnapshot::oops_do(OopClosure* f) { f->do_oop(&_threadObj); f->do_oop(&_blocker_object); f->do_oop(&_blocker_object_owner); if (_stack_trace != NULL) { _stack_trace->oops_do(f); } if (_concurrent_locks != NULL) { _concurrent_locks->oops_do(f); } } void ThreadSnapshot::metadata_do(void f(Metadata*)) { if (_stack_trace != NULL) { _stack_trace->metadata_do(f); } } DeadlockCycle::DeadlockCycle() { _is_deadlock = false; _threads = new (ResourceObj::C_HEAP, mtInternal) GrowableArray(INITIAL_ARRAY_SIZE, true); _next = NULL; } DeadlockCycle::~DeadlockCycle() { delete _threads; } void DeadlockCycle::print_on_with(ThreadsList * t_list, outputStream* st) const { st->cr(); st->print_cr("Found one Java-level deadlock:"); st->print("============================="); JavaThread* currentThread; ObjectMonitor* waitingToLockMonitor; oop waitingToLockBlocker; int len = _threads->length(); for (int i = 0; i < len; i++) { currentThread = _threads->at(i); waitingToLockMonitor = (ObjectMonitor*)currentThread->current_pending_monitor(); waitingToLockBlocker = currentThread->current_park_blocker(); st->cr(); st->print_cr("\"%s\":", currentThread->get_thread_name()); const char* owner_desc = ",\n which is held by"; if (waitingToLockMonitor != NULL) { st->print(" waiting to lock monitor " INTPTR_FORMAT, p2i(waitingToLockMonitor)); oop obj = (oop)waitingToLockMonitor->object(); if (obj != NULL) { st->print(" (object " INTPTR_FORMAT ", a %s)", p2i(obj), obj->klass()->external_name()); if (!currentThread->current_pending_monitor_is_from_java()) { owner_desc = "\n in JNI, which is held by"; } } else { // No Java object associated - a JVMTI raw monitor owner_desc = " (JVMTI raw monitor),\n which is held by"; } currentThread = Threads::owning_thread_from_monitor_owner(t_list, (address)waitingToLockMonitor->owner()); if (currentThread == NULL) { // The deadlock was detected at a safepoint so the JavaThread // that owns waitingToLockMonitor should be findable, but // if it is not findable, then the previous currentThread is // blocked permanently. st->print("%s UNKNOWN_owner_addr=" PTR_FORMAT, owner_desc, p2i(waitingToLockMonitor->owner())); continue; } } else { st->print(" waiting for ownable synchronizer " INTPTR_FORMAT ", (a %s)", p2i(waitingToLockBlocker), waitingToLockBlocker->klass()->external_name()); assert(waitingToLockBlocker->is_a(SystemDictionary::abstract_ownable_synchronizer_klass()), "Must be an AbstractOwnableSynchronizer"); oop ownerObj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(waitingToLockBlocker); currentThread = java_lang_Thread::thread(ownerObj); assert(currentThread != NULL, "AbstractOwnableSynchronizer owning thread is unexpectedly NULL"); } st->print("%s \"%s\"", owner_desc, currentThread->get_thread_name()); } st->cr(); st->cr(); // Print stack traces bool oldJavaMonitorsInStackTrace = JavaMonitorsInStackTrace; JavaMonitorsInStackTrace = true; st->print_cr("Java stack information for the threads listed above:"); st->print_cr("==================================================="); for (int j = 0; j < len; j++) { currentThread = _threads->at(j); st->print_cr("\"%s\":", currentThread->get_thread_name()); currentThread->print_stack_on(st); } JavaMonitorsInStackTrace = oldJavaMonitorsInStackTrace; } ThreadsListEnumerator::ThreadsListEnumerator(Thread* cur_thread, bool include_jvmti_agent_threads, bool include_jni_attaching_threads) { assert(cur_thread == Thread::current(), "Check current thread"); int init_size = ThreadService::get_live_thread_count(); _threads_array = new GrowableArray(init_size); for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) { // skips JavaThreads in the process of exiting // and also skips VM internal JavaThreads // Threads in _thread_new or _thread_new_trans state are included. // i.e. threads have been started but not yet running. if (jt->threadObj() == NULL || jt->is_exiting() || !java_lang_Thread::is_alive(jt->threadObj()) || jt->is_hidden_from_external_view()) { continue; } // skip agent threads if (!include_jvmti_agent_threads && jt->is_jvmti_agent_thread()) { continue; } // skip jni threads in the process of attaching if (!include_jni_attaching_threads && jt->is_attaching_via_jni()) { continue; } instanceHandle h(cur_thread, (instanceOop) jt->threadObj()); _threads_array->append(h); } }