The following test failed in the JDK21 CI:

runtime/handshake/HandshakeDirectTest.java

Here's a snippet from the log file:

#section:main
----------messages:(6/379)----------
command: main -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI HandshakeDirectTest
reason: User specified action: run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI HandshakeDirectTest
started: Tue Apr 11 17:19:32 GMT 2023
Mode: othervm [/othervm specified]
finished: Tue Apr 11 17:19:35 GMT 2023
elapsed time (seconds): 2.9
----------configuration:(0/0)----------
----------System.out:(0/0)----------
----------System.err:(0/0)----------
----------rerun:(35/8608)*----------

<snip>

result: Failed. Unexpected exit from test [exit code: 134]

No indication of an error or a failure by the test other than the exit code of 134.
No hs_err_pid file. What the heck happened here?