OpenJDK 11 hangs in GC during debugging

Issue

• pstack output shows the following 2 threads deadlocked:

Thread 88 (Thread 0x7fffb4378700 (LWP 50344)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007ffff688d3e3 in os::PlatformEvent::park (this=0x7ffff0756100) at src/hotspot/os/posix/os_posix.cpp:2003
#2  0x00007ffff668f57c in SimpleEnter (Self=<optimized out>, this=<optimized out>) at src/hotspot/share/prims/jvmtiRawMonitor.cpp:150
#3  JvmtiRawMonitor::raw_enter (this=this@entry=0x7ffff07c0000, __the_thread__=__the_thread__@entry=0x7ffff0755800) at src/hotspot/share/prims/jvmtiRawMonitor.cpp:304
#4  0x00007ffff6671cb8 in JvmtiEnv::RawMonitorEnter (this=<optimized out>, rmonitor=0x7ffff07c0000) at src/hotspot/share/prims/jvmtiEnv.cpp:3324
#5  0x00007ffff49c4a7b in debugMonitorEnter (monitor=0x7ffff07c0000) at src/jdk.jdwp.agent/share/native/libjdwp/util.c:1043
#6  0x00007ffff49a9758 in cbTrackingObjectFree (jvmti_env=<optimized out>, tag=140729502422448) at src/jdk.jdwp.agent/share/native/libjdwp/classTrack.c:67
#7  0x00007ffff667fe1d in JvmtiExport::post_object_free (env=0x7ffff07c00f0, tag=140729502422448) at src/hotspot/share/prims/jvmtiExport.cpp:1470
#8  0x00007ffff66a098c in JvmtiTagMap::do_weak_oops (this=0x7ffff07c1940, is_alive=is_alive@entry=0x7fffb4377380, f=f@entry=0x7ffff7182150 <do_nothing_cl>) at src/hotspot/share/prims/jvmtiTagMap.cpp:3377
#9  0x00007ffff66a0ac5 in JvmtiTagMap::weak_oops_do (is_alive=is_alive@entry=0x7fffb4377380, f=f@entry=0x7ffff7182150 <do_nothing_cl>) at src/hotspot/share/prims/jvmtiTagMap.cpp:3325
#10 0x00007ffff667eeca in JvmtiExport::weak_oops_do (is_alive=is_alive@entry=0x7fffb4377380, f=f@entry=0x7ffff7182150 <do_nothing_cl>) at src/hotspot/share/prims/jvmtiExport.cpp:2590
#11 0x00007ffff6b44d11 in WeakProcessor::weak_oops_do (is_alive=is_alive@entry=0x7fffb4377380, keep_alive=0x7ffff7182150 <do_nothing_cl>) at src/hotspot/share/gc/shared/weakProcessor.cpp:38
#12 0x00007ffff640e9a3 in G1ConcurrentMark::weak_refs_work (this=this@entry=0x7ffff00708f0, clear_all_soft_refs=clear_all_soft_refs@entry=false) at src/hotspot/share/gc/g1/g1ConcurrentMark.cpp:1674
#13 0x00007ffff640fc59 in G1ConcurrentMark::remark (this=0x7ffff00708f0) at src/hotspot/share/gc/g1/g1ConcurrentMark.cpp:1163
#14 0x00007ffff6b36136 in VM_CGC_Operation::doit (this=0x7fffd4d3bdb0) at src/hotspot/share/gc/g1/vm_operations_g1.cpp:210
#15 0x00007ffff6b2dea0 in VM_Operation::evaluate (this=this@entry=0x7fffd4d3bdb0) at src/hotspot/share/runtime/vmOperations.cpp:67
#16 0x00007ffff6b33d3f in VMThread::evaluate_operation (this=this@entry=0x7ffff0755800, op=0x7fffd4d3bdb0) at src/hotspot/share/runtime/vmThread.cpp:413
#17 0x00007ffff6b341be in VMThread::loop (this=this@entry=0x7ffff0755800) at src/hotspot/share/runtime/vmThread.cpp:548
#18 0x00007ffff6b3472c in VMThread::run (this=0x7ffff0755800) at src/hotspot/share/runtime/vmThread.cpp:310
#19 0x00007ffff6abefea in Thread::call_run (this=0x7ffff0755800) at src/hotspot/share/runtime/thread.cpp:380
#20 0x00007ffff6883a48 in thread_native_entry (thread=0x7ffff0755800) at src/hotspot/os/linux/os_linux.cpp:784
#21 0x00007ffff79b0ea5 in start_thread (arg=0x7fffb4378700) at pthread_create.c:307
#22 0x00007ffff72c496d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 4 (Thread 0x7ffed41e3700 (LWP 72615)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007ffff688d3e3 in os::PlatformEvent::park (this=0x7ffe34013b00) at src/hotspot/os/posix/os_posix.cpp:2003
#2  0x00007ffff6835008 in ParkCommon (timo=0, ev=0x7ffe34013b00) at src/hotspot/share/runtime/mutex.cpp:404
#3  Monitor::ILock (this=this@entry=0x7ffff00159c0, Self=Self@entry=0x7ffef4036000) at src/hotspot/share/runtime/mutex.cpp:466
#4  0x00007ffff6835a48 in lock_without_safepoint_check (Self=0x7ffef4036000, this=0x7ffff00159c0) at src/hotspot/share/runtime/mutex.cpp:938
#5  Monitor::lock_without_safepoint_check (this=0x7ffff00159c0) at src/hotspot/share/runtime/mutex.cpp:944
#6  0x00007ffff6937d4d in SafepointSynchronize::block (thread=0x7ffef4036000) at src/hotspot/share/runtime/safepoint.cpp:910
#7  0x00007ffff6ab9e8e in block_if_requested_local_poll (thread=0x7ffef4036000) at src/hotspot/share/runtime/safepointMechanism.inline.hpp:63
#8  block_if_requested (thread=0x7ffef4036000) at src/hotspot/share/runtime/safepointMechanism.inline.hpp:73
#9  JavaThread::check_safepoint_and_suspend_for_native_trans (thread=thread@entry=0x7ffef4036000) at src/hotspot/share/runtime/thread.cpp:2505
#10 0x00007ffff6612d1d in ThreadStateTransition::transition_from_native (thread=thread@entry=0x7ffef4036000, to=_thread_in_vm) at src/hotspot/share/runtime/interfaceSupport.inline.hpp:168
#11 0x00007ffff66217b0 in trans_from_native (to=_thread_in_vm, this=0x7ffed41e1560) at src/hotspot/share/runtime/interfaceSupport.inline.hpp:179
#12 ThreadInVMfromNative (thread=0x7ffef4036000, this=0x7ffed41e1560) at src/hotspot/share/runtime/interfaceSupport.inline.hpp:267
#13 jvmti_Allocate (env=0x7ffff000bd70, size=24, mem_ptr=0x7ffed41e15c0, this=<optimized out>) at build/hotspot/variant-server/gensrc/jvmtifiles/jvmtiEnter.cpp:336
#14 0x00007ffff49c6786 in jvmtiAllocate (numBytes=numBytes@entry=24) at src/jdk.jdwp.agent/share/native/libjdwp/util.c:1808
#15 0x00007ffff49a92ad in bagCreateBag (itemSize=itemSize@entry=8, initialAllocation=initialAllocation@entry=10) at src/jdk.jdwp.agent/share/native/libjdwp/bag.c:40
#16 0x00007ffff49a97b0 in classTrack_processUnloads (env=env@entry=0x7ffef4036348) at src/jdk.jdwp.agent/share/native/libjdwp/classTrack.c:91
#17 0x00007ffff49b1253 in event_callback (env=env@entry=0x7ffef4036348, evinfo=evinfo@entry=0x7ffed41e1700) at src/jdk.jdwp.agent/share/native/libjdwp/eventHandler.c:583
#18 0x00007ffff49b215e in cbClassPrepare (jvmti_env=<optimized out>, env=0x7ffef4036348, thread=0x7ffee00010d0, klass=0x7ffee00010d8) at src/jdk.jdwp.agent/share/native/libjdwp/eventHandler.c:892
#19 0x00007ffff6681094 in JvmtiExport::post_class_prepare (thread=0x7ffef4036000, klass=0x840362840) at src/hotspot/share/prims/jvmtiExport.cpp:1337
#20 0x00007ffff64cf5c8 in InstanceKlass::link_class_impl (this=0x840362840, throw_verifyerror=<optimized out>, __the_thread__=0x7ffef4036000) at src/hotspot/share/oops/instanceKlass.cpp:838
#21 0x00007ffff64cf14e in InstanceKlass::link_class_impl (this=0x840355040, throw_verifyerror=throw_verifyerror@entry=true, __the_thread__=__the_thread__@entry=0x7ffef4036000) at src/hotspot/share/oops/instanceKlass.cpp:753
#22 0x00007ffff64cf5ee in InstanceKlass::link_class (this=this@entry=0x840355040, __the_thread__=__the_thread__@entry=0x7ffef4036000) at src/hotspot/share/oops/instanceKlass.cpp:697
#23 0x00007ffff65b16a9 in get_class_declared_methods_helper (env=env@entry=0x7ffef4036348, ofClass=ofClass@entry=0x7ffed41e1d10, publicOnly=publicOnly@entry=1 '\001', want_constructor=want_constructor@entry=true, klass=0x8002b7898, __the_thread__=__the_thread__@entry=0x7ffef4036000) at src/hotspot/share/prims/jvm.cpp:1814
#24 0x00007ffff65b1cb9 in JVM_GetClassDeclaredConstructors (env=0x7ffef4036348, ofClass=0x7ffed41e1d10, publicOnly=<optimized out>) at src/hotspot/share/prims/jvm.cpp:1878
#25 0x00007fffdfaff4fb in ?? ()
#26 0x0000000508398330 in ?? ()
#27 0x00007ffff62a3823 in CollectedHeap::array_allocate (this=<optimized out>, klass=<optimized out>, size=<optimized out>, length=<optimized out>, do_zero=<optimized out>, __the_thread__=<optimized out>) at src/hotspot/share/gc/shared/collectedHeap.cpp:457
#28 0x00007fffd81b5edc in ?? ()
#29 0x00007ffed41e1ec0 in ?? ()
#30 0x00007ffff64d80eb in InstanceKlass::allocate_objArray (this=<optimized out>, n=<optimized out>, length=0, __the_thread__=0x7ffef4036000) at src/hotspot/share/oops/instanceKlass.cpp:1221
#31 0x00007fffd769dda8 in ?? ()
#32 0x0000000000000000 in ?? ()