The following test failed in the JDK20 CI:

applications/javafuzzer/MediumTest.java

Here's a snippet from the log file:

Summary of the JavaFuzzer run:
------------------------------
Host: ol8-x64-123246
Tests: 12 x 50
Args: -conf config.yml

Started at: Fri Nov 18 02:23:43 UTC 2022


r4- 50: 33 passed, 0 crashes, 0 fails, 0 hangs, 0 incorrect tests, 17 Reference Java failures
r3- 50: 38 passed, 0 crashes, 0 fails, 0 hangs, 0 incorrect tests, 12 Reference Java failures
r11- 50: 27 passed, 0 crashes, 0 fails, 0 hangs, 0 incorrect tests, 23 Reference Java failures
r8- 50: 36 passed, 0 crashes, 0 fails, 0 hangs, 0 incorrect tests, 14 Reference Java failures
r12- 50: 28 passed, 2 crashes, 0 fails, 0 hangs, 0 incorrect tests, 21 Reference Java failures
r1- 50: 34 passed, 0 crashes, 0 fails, 0 hangs, 0 incorrect tests, 16 Reference Java failures
r7- 50: 36 passed, 0 crashes, 0 fails, 0 hangs, 0 incorrect tests, 14 Reference Java failures
r2- 50: 33 passed, 0 crashes, 0 fails, 0 hangs, 0 incorrect tests, 17 Reference Java failures
r10- 50: 29 passed, 0 crashes, 0 fails, 0 hangs, 0 incorrect tests, 21 Reference Java failures
r6- 50: 29 passed, 0 crashes, 0 fails, 0 hangs, 0 incorrect tests, 21 Reference Java failures
r9- 50: 31 passed, 0 crashes, 0 fails, 0 hangs, 0 incorrect tests, 19 Reference Java failures
r5- 50: 28 passed, 0 crashes, 0 fails, 0 hangs, 0 incorrect tests, 22 Reference Java failures

Finished at: Fri Nov 18 03:51:22 UTC 2022


#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (/opt/mach5/mesos/work_dir/slaves/0c72054a-24ab-4dbb-944f-97f9341a1b96-S122514/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/ccc22c45-6ee4-44e3-a220-fcb16ee5313c/runs/d541d200-a135-4df8-9627-2aff32b06bf0/workspace/open/src/hotspot/share/opto/block.cpp:1357), pid=1409813, tid=1409840
# assert(n->is_Root() || n->is_Region() || n->is_Phi() || n->is_MachMerge() || def_block->dominates(block)) failed: uses must be dominated by definitions
#
# JRE version: Java(TM) SE Runtime Environment (20.0+24) (fastdebug build 20-ea+24-1796)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (fastdebug 20-ea+24-1796, compiled mode, sharing, tiered, compressed oops, compressed class ptrs, g1 gc, linux-amd64)
# Problematic frame:
# V [libjvm.so+0x76ba81] PhaseCFG::verify() const+0x1d1
#
# Core dump will be written. Default location: Core dumps may be processed with "/opt/core.sh %p" (or dumping to /tmp/fuzzer.tmp.BfribQfP9J/core.1409813)
#
# If you would like to submit a bug report, please visit:
# https://bugreport.java.com/bugreport/crash.jsp
#

#
# A fatal error has been detected by the Java Runtime Environment:
#
# Internal Error (/opt/mach5/mesos/work_dir/slaves/0c72054a-24ab-4dbb-944f-97f9341a1b96-S122514/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/ccc22c45-6ee4-44e3-a220-fcb16ee5313c/runs/d541d200-a135-4df8-9627-2aff32b06bf0/workspace/open/src/hotspot/share/opto/block.cpp:1357), pid=1410177, tid=1410192
# assert(n->is_Root() || n->is_Region() || n->is_Phi() || n->is_MachMerge() || def_block->dominates(block)) failed: uses must be dominated by definitions
#
# JRE version: Java(TM) SE Runtime Environment (20.0+24) (fastdebug build 20-ea+24-1796)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (fastdebug 20-ea+24-1796, compiled mode, sharing, compressed oops, compressed class ptrs, g1 gc, linux-amd64)
# Problematic frame:
# V [libjvm.so+0x76ba81] PhaseCFG::verify() const+0x1d1
#
# Core dump will be written. Default location: Core dumps may be processed with "/opt/core.sh %p" (or dumping to /tmp/fuzzer.tmp.BfribQfP9J/core.1410177)
#
# If you would like to submit a bug report, please visit:
# https://bugreport.java.com/bugreport/crash.jsp
#

[2022-11-18T03:51:22.333950639Z] Waiting for completion for process 1404536
[2022-11-18T03:51:22.334143063Z] Waiting for completion finished for process 1404536
----------System.err:(13/728)----------
java.lang.RuntimeException: assertEquals: expected 1 to equal 2
at jdk.test.lib.Asserts.fail(Asserts.java:594)
at jdk.test.lib.Asserts.assertEquals(Asserts.java:205)
at jdk.test.lib.Asserts.assertEquals(Asserts.java:189)
at applications.javafuzzer.JavaFuzzerRunner.main(JavaFuzzerRunner.java:245)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:578)
at com.sun.javatest.regtest.agent.MainActionHelper$AgentVMRunnable.run(MainActionHelper.java:312)
at java.base/java.lang.Thread.run(Thread.java:1591)

JavaTest Message: Test threw exception: java.lang.RuntimeException
JavaTest Message: shutting down test

result: Failed. Execution failed: `main' threw exception: java.lang.RuntimeException: assertEquals: expected 1 to equal 2


Here's the crashing thread's stack from hs_err_pid1409813.log:

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

Current thread (0x00007f1d3433d2a0): JavaThread "C2 CompilerThread0" daemon [_thread_in_native, id=1409840, stack(0x00007f1d0b726000,0x00007f1d0b827000)]


Current CompileTask:
C2: 377 12 b 4 Test::vMeth1 (274 bytes)

Stack: [0x00007f1d0b726000,0x00007f1d0b827000], sp=0x00007f1d0b821fa0, free space=1007k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0x76ba81] PhaseCFG::verify() const+0x1d1 (block.cpp:1357)
V [libjvm.so+0xaf4d84] Compile::Code_Gen()+0x2d4 (compile.cpp:2949)
V [libjvm.so+0xafad6d] Compile::Compile(ciEnv*, ciMethod*, int, Options, DirectiveSet*)+0x19ad (compile.cpp:864)
V [libjvm.so+0x90b167] C2Compiler::compile_method(ciEnv*, ciMethod*, int, bool, DirectiveSet*)+0x4e7 (c2compiler.cpp:113)
V [libjvm.so+0xb07d7c] CompileBroker::invoke_compiler_on_method(CompileTask*)+0xa7c (compileBroker.cpp:2237)
V [libjvm.so+0xb08b88] CompileBroker::compiler_thread_loop()+0x608 (compileBroker.cpp:1916)
V [libjvm.so+0x107b776] JavaThread::thread_main_inner()+0x206 (javaThread.cpp:699)
V [libjvm.so+0x1a7afc0] Thread::call_run()+0x100 (thread.cpp:224)
V [libjvm.so+0x1712143] thread_native_entry(Thread*)+0x103 (os_linux.cpp:710)