The following test failed in the JDK20 CI:

serviceability/sa/ClhsdbFindPC.java#xcomp-process

Here's a snippet from the log file:

hsdb> + quit
java version "20-ea" 2023-03-21
Java(TM) SE Runtime Environment (fastdebug build 20-ea+2-39)
Java HotSpot(TM) 64-Bit Server VM (fastdebug build 20-ea+2-39, mixed mode)
ERROR: catch_mach_exception_raise: Message doesn't denote a Unix soft signal. exception_type = 5, codes[0] = 65539, codes[num_codes -1] = 0x4, num_codes = 2
ERROR: attach: wait_for_exception: catch_mach_exception_raise() got unknown exception type
ERROR: attach: wait_for_exception() failed. Retried 0 times
Unable to connect to process ID 77015:

Can't attach to the process. Issues with reception of the exception message.
sun.jvm.hotspot.debugger.DebuggerException: Can't attach to the process. Issues with reception of the exception message.
at jdk.hotspot.agent/sun.jvm.hotspot.debugger.bsd.BsdDebuggerLocal$BsdDebuggerLocalWorkerThread.execute(BsdDebuggerLocal.java:168)
at jdk.hotspot.agent/sun.jvm.hotspot.debugger.bsd.BsdDebuggerLocal.attach(BsdDebuggerLocal.java:282)
at jdk.hotspot.agent/sun.jvm.hotspot.HotSpotAgent.attachDebugger(HotSpotAgent.java:636)
at jdk.hotspot.agent/sun.jvm.hotspot.HotSpotAgent.setupDebuggerDarwin(HotSpotAgent.java:624)
at jdk.hotspot.agent/sun.jvm.hotspot.HotSpotAgent.setupDebugger(HotSpotAgent.java:372)
at jdk.hotspot.agent/sun.jvm.hotspot.HotSpotAgent.go(HotSpotAgent.java:337)
at jdk.hotspot.agent/sun.jvm.hotspot.HotSpotAgent.attach(HotSpotAgent.java:142)
at jdk.hotspot.agent/sun.jvm.hotspot.CLHSDB.attachDebugger(CLHSDB.java:188)
at jdk.hotspot.agent/sun.jvm.hotspot.CLHSDB.run(CLHSDB.java:67)
at jdk.hotspot.agent/sun.jvm.hotspot.CLHSDB.main(CLHSDB.java:44)
at jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.runCLHSDB(SALauncher.java:281)
at jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.main(SALauncher.java:500)
Caused by: sun.jvm.hotspot.debugger.DebuggerException: Can't attach to the process. Issues with reception of the exception message.
at jdk.hotspot.agent/sun.jvm.hotspot.debugger.bsd.BsdDebuggerLocal.attach0(Native Method)
at jdk.hotspot.agent/sun.jvm.hotspot.debugger.bsd.BsdDebuggerLocal$1AttachTask.doit(BsdDebuggerLocal.java:273)
at jdk.hotspot.agent/sun.jvm.hotspot.debugger.bsd.BsdDebuggerLocal$BsdDebuggerLocalWorkerThread.run(BsdDebuggerLocal.java:143)

[2022-06-14T02:04:22.088214Z] Waiting for completion for process 77119
[2022-06-14T02:04:22.088251Z] Waiting for completion finished for process 77119
 LingeredApp stdout: [];
 LingeredApp stderr: [java version "20-ea" 2023-03-21
Java(TM) SE Runtime Environment (fastdebug build 20-ea+2-39)
Java HotSpot(TM) 64-Bit Server VM (fastdebug build 20-ea+2-39, compiled mode)
]
 LingeredApp exitValue = 137
----------System.err:(52/3433)----------
java version "20-ea" 2023-03-21
Java(TM) SE Runtime Environment (fastdebug build 20-ea+2-39)
Java HotSpot(TM) 64-Bit Server VM (fastdebug build 20-ea+2-39, mixed mode)
 stdout: [Attaching to process 77015, please wait...
hsdb> hsdb> + verbose true
hsdb> + findpc 0x0000000114604ce8
Command not valid until attached to a VM
hsdb> + quit
];
 stderr: [java version "20-ea" 2023-03-21
Java(TM) SE Runtime Environment (fastdebug build 20-ea+2-39)
Java HotSpot(TM) 64-Bit Server VM (fastdebug build 20-ea+2-39, mixed mode)
ERROR: catch_mach_exception_raise: Message doesn't denote a Unix soft signal. exception_type = 5, codes[0] = 65539, codes[num_codes -1] = 0x4, num_codes = 2
ERROR: attach: wait_for_exception: catch_mach_exception_raise() got unknown exception type
ERROR: attach: wait_for_exception() failed. Retried 0 times
Unable to connect to process ID 77015:

Can't attach to the process. Issues with reception of the exception message.
sun.jvm.hotspot.debugger.DebuggerException: Can't attach to the process. Issues with reception of the exception message.
at jdk.hotspot.agent/sun.jvm.hotspot.debugger.bsd.BsdDebuggerLocal$BsdDebuggerLocalWorkerThread.execute(BsdDebuggerLocal.java:168)
at jdk.hotspot.agent/sun.jvm.hotspot.debugger.bsd.BsdDebuggerLocal.attach(BsdDebuggerLocal.java:282)
at jdk.hotspot.agent/sun.jvm.hotspot.HotSpotAgent.attachDebugger(HotSpotAgent.java:636)
at jdk.hotspot.agent/sun.jvm.hotspot.HotSpotAgent.setupDebuggerDarwin(HotSpotAgent.java:624)
at jdk.hotspot.agent/sun.jvm.hotspot.HotSpotAgent.setupDebugger(HotSpotAgent.java:372)
at jdk.hotspot.agent/sun.jvm.hotspot.HotSpotAgent.go(HotSpotAgent.java:337)
at jdk.hotspot.agent/sun.jvm.hotspot.HotSpotAgent.attach(HotSpotAgent.java:142)
at jdk.hotspot.agent/sun.jvm.hotspot.CLHSDB.attachDebugger(CLHSDB.java:188)
at jdk.hotspot.agent/sun.jvm.hotspot.CLHSDB.run(CLHSDB.java:67)
at jdk.hotspot.agent/sun.jvm.hotspot.CLHSDB.main(CLHSDB.java:44)
at jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.runCLHSDB(SALauncher.java:281)
at jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.main(SALauncher.java:500)
Caused by: sun.jvm.hotspot.debugger.DebuggerException: Can't attach to the process. Issues with reception of the exception message.
at jdk.hotspot.agent/sun.jvm.hotspot.debugger.bsd.BsdDebuggerLocal.attach0(Native Method)
at jdk.hotspot.agent/sun.jvm.hotspot.debugger.bsd.BsdDebuggerLocal$1AttachTask.doit(BsdDebuggerLocal.java:273)
at jdk.hotspot.agent/sun.jvm.hotspot.debugger.bsd.BsdDebuggerLocal$BsdDebuggerLocalWorkerThread.run(BsdDebuggerLocal.java:143)
]
 exitValue = 0

java.io.IOException: LingeredApp terminated with non-zero exit code 137
at jdk.test.lib.apps.LingeredApp.stopApp(LingeredApp.java:426)
at jdk.test.lib.apps.LingeredApp.stopApp(LingeredApp.java:484)
at ClhsdbFindPC.testFindPC(ClhsdbFindPC.java:309)
at ClhsdbFindPC.main(ClhsdbFindPC.java:328)
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.MainWrapper$MainThread.run(MainWrapper.java:127)
at java.base/java.lang.Thread.run(Thread.java:1596)

JavaTest Message: Test threw exception: java.io.IOException: LingeredApp terminated with non-zero exit code 137
JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: java.io.IOException: LingeredApp terminated with non-zero exit code 137
----------rerun:(33/7100)*----------

This failure mode is very similar to the following resolved bug:

JDK-8283179 SA tests fail with "ERROR: catch_mach_exception_raise: Message doesn't denote a Unix soft signal."