The following test failed in the JDK15 CI:

serviceability/sa/ClhsdbJhisto.java

Here's a snippet from the log file:

----------System.err:(54/4514)----------
Command line: ['/mesos/work_dir/jib-master/install/jdk-15+12-377/macosx-x64-debug.jdk/jdk-15/fastdebug/bin/java' '-cp' '/mesos/work_dir/slaves/7cfa21b9-afde-4338-a459-d3e0a13ec793-S841/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/babc0bef-3a44-4ba8-9518-9ddd53c5785e/runs/4b224af4-0348-4587-b6b1-67a93629484c/testoutput/test-support/jtreg_open_test_hotspot_jtreg_hotspot_cds_relocation/classes/0/serviceability/sa/ClhsdbJhisto.d:/mesos/work_dir/slaves/7cfa21b9-afde-4338-a459-d3e0a13ec793-S841/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/babc0bef-3a44-4ba8-9518-9ddd53c5785e/runs/4b224af4-0348-4587-b6b1-67a93629484c/testoutput/test-support/jtreg_open_test_hotspot_jtreg_hotspot_cds_relocation/classes/0/test/lib' 'LingeredAppWithInterface' '07df9948-374d-4ee1-b04e-8d54d1ed0591.lck' ]
 stdout: [hsdb> hsdb> !!! Unschedulable graph !!!
B557 idom=B521 depth=158 2510 Phi === 1798 2511 2546 2547 2548 [[ 1783 1745 ]] #memory Memory: @BotPTR *+bot, idx=Bot; !jvms: Object::<init> @ bci:0 ReflectionFactory$GetReflectionFactoryAction::<init> @ bci:1 Class::getReflectionFactory @ bci:10 Class::getConstructor @ bci:18 VMObjectFactory::newObject @ bci:16 InstanceKlass::getFields @ bci:22 InstanceKlass::getFieldSignature @ bci:1 InstanceKlass::<init> @ bci:37
B544 idom=B542 depth=167 1746 decodeKlass_not_null === _ 2572 [[ 1747 1745 ]] klass sun/jvm/hotspot/debugger/Address: 0x00007f98f7be0a00 * Interface:klass sun/jvm/hotspot/debugger/Address: 0x00007f98f7be0a00 *
Failing node: 1745 loadKlass === _ 2510 1746 [[ 1744 ]] * Klass: *
# To suppress the following error report, specify this argument
# after -XX: or in .hotspotrc: SuppressErrorAt=/gcm.cpp:276
#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (/scratch/mesos/slaves/90726e33-be99-4e27-9d68-25dad266ef13-S2495/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/cbf54de2-c7d8-4123-80b0-2ceb6113e621/runs/d021cdfa-e0f2-4ba6-bc56-b5234c0cd94e/workspace/open/src/hotspot/share/opto/gcm.cpp:276), pid=53994, tid=43267
# assert(false) failed: unscheduable graph
#
# JRE version: Java(TM) SE Runtime Environment (15.0+12) (fastdebug build 15-ea+12-377)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (fastdebug 15-ea+12-377, mixed mode, sharing, tiered, compressed oops, g1 gc, bsd-amd64)
# Core dump will be written. Default location: core.53994
#
# An error report file with more information is saved as:
# /mesos/work_dir/slaves/7cfa21b9-afde-4338-a459-d3e0a13ec793-S841/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/babc0bef-3a44-4ba8-9518-9ddd53c5785e/runs/4b224af4-0348-4587-b6b1-67a93629484c/testoutput/test-support/jtreg_open_test_hotspot_jtreg_hotspot_cds_relocation/scratch/0/hs_err_pid53994.log
#
# Compiler replay data is saved as:
# /mesos/work_dir/slaves/7cfa21b9-afde-4338-a459-d3e0a13ec793-S841/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/babc0bef-3a44-4ba8-9518-9ddd53c5785e/runs/4b224af4-0348-4587-b6b1-67a93629484c/testoutput/test-support/jtreg_open_test_hotspot_jtreg_hotspot_cds_relocation/scratch/0/replay_pid53994.log
#
# If you would like to submit a bug report, please visit:
# https://bugreport.java.com/bugreport/crash.jsp
#
Current thread is 43267
Dumping core ...


Here's the crashing thread's stack:

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

Current thread (0x00007f98f6857800): JavaThread "C2 CompilerThread0" daemon [_thread_in_native, id=43267, stack(0x000070000f519000,0x000070000f619000)]


Current CompileTask:
C2: 6452 641 4 sun.jvm.hotspot.oops.InstanceKlass::<init> (48 bytes)

Stack: [0x000070000f519000,0x000070000f619000], sp=0x000070000f614b70, free space=1006k
Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.dylib+0xb481b3] VMError::report_and_die(int, char const*, char const*, __va_list_tag*, Thread*, unsigned char*, void*, void*, char const*, int, unsigned long)+0x6e5
V [libjvm.dylib+0xb488cf] VMError::report_and_die(Thread*, void*, char const*, int, char const*, char const*, __va_list_tag*)+0x47
V [libjvm.dylib+0x3384d4] report_vm_error(char const*, int, char const*, char const*, ...)+0x145
V [libjvm.dylib+0x49c17b] assert_dom(Block*, Block*, Node*, PhaseCFG const*)+0x15d
V [libjvm.dylib+0x497608] PhaseCFG::schedule_early(VectorSet&, Node_Stack&)+0x29a
V [libjvm.dylib+0x499cc9] PhaseCFG::global_code_motion()+0x1ad
V [libjvm.dylib+0x49a291] PhaseCFG::do_global_code_motion()+0x41
V [libjvm.dylib+0x3042d4] Compile::Code_Gen()+0x224
V [libjvm.dylib+0x301fbb] Compile::Compile(ciEnv*, C2Compiler*, ciMethod*, int, bool, bool, bool, DirectiveSet*)+0xbf1
V [libjvm.dylib+0x2542c2] C2Compiler::compile_method(ciEnv*, ciMethod*, int, DirectiveSet*)+0xe8
V [libjvm.dylib+0x31432e] CompileBroker::invoke_compiler_on_method(CompileTask*)+0x664
V [libjvm.dylib+0x313abf] CompileBroker::compiler_thread_loop()+0x283
V [libjvm.dylib+0xabf38b] JavaThread::thread_main_inner()+0x1a1
V [libjvm.dylib+0xabef3d] JavaThread::run()+0x23d
V [libjvm.dylib+0xabb8e1] Thread::call_run()+0x11b
V [libjvm.dylib+0x93529c] thread_native_entry(Thread*)+0xe0
C [libsystem_pthread.dylib+0x3661] _pthread_body+0x154
C [libsystem_pthread.dylib+0x350d] _pthread_body+0x0
C [libsystem_pthread.dylib+0x2bf9] thread_start+0xd