The following test failed in the JDK15 CI:

applications/kitchensink/Kitchensink24HStress.java

Here's a snippet from the log file:

[stress.process.out] # A fatal error has been detected by the Java Runtime Environment:
[stress.process.out] #
[stress.process.out] # Internal Error (t:/workspace/open/src/hotspot/share/runtime/mutex.cpp:458), pid=13820, tid=39856
[stress.process.out] # fatal error: acquiring lock JfrStacktrace_lock/5 out of order with lock CodeCache_lock/5 -- possible deadlock
[stress.process.out] #
[stress.process.out] # JRE version: Java(TM) SE Runtime Environment (15.0+18) (fastdebug build 15-ea+18-724)
[stress.process.out] # Java VM: Java HotSpot(TM) 64-Bit Server VM (fastdebug 15-ea+18-724, mixed mode, tiered, z gc, windows-amd64)
[stress.process.out] # Core dump will be written. Default location: T:\\testoutput\\test-support\\jtreg_closed_test_hotspot_jtreg_applications_kitchensink_Kitchensink24HStress_java\\scratch\\0\\hs_err_pid13820.mdmp
[stress.process.out] #
[stress.process.out] Unsupported internal testing APIs have been used.
[stress.process.out]
[stress.process.out] # An error report file with more information is saved as:
[stress.process.out] # T:\\testoutput\\test-support\\jtreg_closed_test_hotspot_jtreg_applications_kitchensink_Kitchensink24HStress_java\\scratch\\0\\hs_err_pid13820.log
[stress.process.out] #
[stress.process.out] # If you would like to submit a bug report, please visit:
[stress.process.out] # https://bugreport.java.com/bugreport/crash.jsp


Here's the crashing thread's stack:

--------------- T H R E A D ---------------

Current thread (0x000001d1b2f53200): JavaThread "MemAccessWorkerThread" [_thread_in_vm, id=39856, stack(0x0000004013700000,0x0000004013800000)]

Stack: [0x0000004013700000,0x0000004013800000]
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [jvm.dll+0x9dbcc1] os::platform_print_native_stack+0xf1 (os_windows_x86.cpp:369)
V [jvm.dll+0xbde95b] VMError::report+0xf0b (vmerror.cpp:727)
V [jvm.dll+0xbe020e] VMError::report_and_die+0x8ae (vmerror.cpp:1535)
V [jvm.dll+0xbe0904] VMError::report_and_die+0x64 (vmerror.cpp:1319)
V [jvm.dll+0x414132] report_vm_error+0x102 (debug.cpp:264)
V [jvm.dll+0x98f3ac] Mutex::lock_without_safepoint_check+0x8c (mutex.cpp:135)
V [jvm.dll+0x6346d3] JfrStackTraceRepository::add_trace+0x33 (jfrstacktracerepository.cpp:178)
V [jvm.dll+0x634c8a] JfrStackTraceRepository::record+0x18a (jfrstacktracerepository.cpp:145)
V [jvm.dll+0x6b3dc1] JfrEvent<EventShutdown>::write_event+0x201 (jfrevent.hpp:181)
V [jvm.dll+0xbdfe0c] VMError::report_and_die+0x4ac (vmerror.cpp:1417)
V [jvm.dll+0xbe0904] VMError::report_and_die+0x64 (vmerror.cpp:1319)
V [jvm.dll+0x413e30] report_fatal+0x80 (debug.cpp:286)
V [jvm.dll+0x98f89d] Mutex::set_owner_implementation+0x20d (mutex.cpp:456)
V [jvm.dll+0x6346d3] JfrStackTraceRepository::add_trace+0x33 (jfrstacktracerepository.cpp:178)
V [jvm.dll+0x634c8a] JfrStackTraceRepository::record+0x18a (jfrstacktracerepository.cpp:145)
V [jvm.dll+0xc48770] JfrEvent<EventZPageAllocation>::write_event+0x3e0 (jfrevent.hpp:181)
V [jvm.dll+0xc464d9] ZPageAllocator::alloc_page_common+0x259 (zpageallocator.cpp:438)
V [jvm.dll+0xc45eae] ZPageAllocator::alloc_page+0x4e (zpageallocator.cpp:511)
V [jvm.dll+0xc360e7] ZHeap::alloc_page+0x27 (zheap.cpp:217)
V [jvm.dll+0xc44a52] ZObjectAllocator::alloc_page+0x62 (zobjectallocator.cpp:63)
V [jvm.dll+0xc44894] ZObjectAllocator::alloc_object_in_shared_page+0x74 (zobjectallocator.cpp:93)
V [jvm.dll+0xc44c8d] ZObjectAllocator::alloc_small_object+0x1fd (zobjectallocator.cpp:186)
V [jvm.dll+0xc4d342] ZRelocate::relocate_object_inner+0x1c2 (zrelocate.cpp:114)
V [jvm.dll+0xc4d14e] ZRelocate::relocate_object+0x3e (zrelocate.cpp:146)
V [jvm.dll+0xc29ff5] ZBarrier::relocate+0x155 (zbarrier.cpp:110)
V [jvm.dll+0x187ef] ZBarrier::weak_load_barrier_on_oop_field_preloaded+0x4f (zbarrier.inline.hpp:290)
V [jvm.dll+0x39f6fa] ClassLoaderData::is_alive+0x4a (classloaderdata.cpp:622)
V [jvm.dll+0x8165ec] Klass::subklass+0x3c (klass.cpp:370)
V [jvm.dll+0x4312a1] Dependencies::find_finalizable_subclass+0x31 (dependencies.cpp:1537)
V [jvm.dll+0x42fa1f] Dependencies::DepStream::check_klass_dependency+0x48f (dependencies.cpp:1876)
V [jvm.dll+0x998475] nmethod::check_all_dependencies+0x4a5 (nmethod.cpp:2211)
V [jvm.dll+0x3b66b3] CodeCache::flush_dependents_on+0x193 (codecache.cpp:1200)
V [jvm.dll+0xb399c8] SystemDictionary::parse_stream+0x258 (systemdictionary.cpp:1033)
V [jvm.dll+0xbb5386] Unsafe_DefineAnonymousClass_impl+0x946 (unsafe.cpp:859)
V [jvm.dll+0xbb28b9] Unsafe_DefineAnonymousClass0+0x1c9 (unsafe.cpp:873)
C 0x000001d1f4dda53c

Java frames: (J=compiled Java code, j=interpreted, Vv=VM code)
J 5606 jdk.internal.misc.Unsafe.defineAnonymousClass0(Ljava/lang/Class;[B[Ljava/lang/Object;)Ljava/lang/Class; java.base@15-ea (0 bytes) @ 0x000001d1f4dda49c [0x000001d1f4dda3e0+0x00000000000000bc]
J 110653 c2 java.lang.invoke.Invokers.maybeCustomize(Ljava/lang/invoke/MethodHandle;)V java.base@15-ea (28 bytes) @ 0x000001d1f5a2323c [0x000001d1f5a22de0+0x000000000000045c]
J 114415 c2 applications.kitchensink.process.stress.modules.MemAccessStressModule.testFloatField(Ljava/lang/invoke/VarHandle;Ljava/lang/Object;I)V (180 bytes) @ 0x000001d1f63a62b0 [0x000001d1f63a5840+0x0000000000000a70]
J 115428 c2 applications.kitchensink.process.stress.modules.MemAccessStressModule$$Lambda$159.run()V (56 bytes) @ 0x000001d1f4d17424 [0x000001d1f4d171e0+0x0000000000000244]
j java.lang.Thread.run()V+11 java.base@15-ea
v ~StubRoutines::call_stub