The following test failed in the JDK20 CI:

sun/tools/jhsdb/JStackStressTest.java

Here's a snippet from the log file:

jhsdb jstack stderr:

###### End of all output for iteration 2 which took 19249ms
[2022-08-27T04:26:43.404291900Z] Waiting for completion for process 46936
[2022-08-27T04:26:43.404291900Z] Waiting for completion finished for process 46936
###### Starting jstack iteration 3 against 67088
[2022-08-27T04:26:43.414815900Z] Gathering output for process 59168
[2022-08-27T04:26:52.877476Z] Waiting for completion for process 59168
[2022-08-27T04:26:52.878041300Z] Waiting for completion finished for process 59168
Output and diagnostic info for process 59168 was saved into 'pid-59168-output.log'
jhsdb jstack stdout:
Attaching to process ID 67088, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 20-ea+13-791
Deadlock Detection:

No deadlocks found.

"<null>" #
jhsdb jstack stderr:
sun.jvm.hotspot.debugger.UnalignedAddressException: 8baadbabe
at jdk.hotspot.agent/sun.jvm.hotspot.debugger.windbg.WindbgDebuggerLocal$1.checkAlignment(WindbgDebuggerLocal.java:106)
at jdk.hotspot.agent/sun.jvm.hotspot.debugger.DebuggerBase.readCInteger(DebuggerBase.java:357)
at jdk.hotspot.agent/sun.jvm.hotspot.debugger.DebuggerBase.readAddressValue(DebuggerBase.java:462)
at jdk.hotspot.agent/sun.jvm.hotspot.debugger.windbg.WindbgDebuggerLocal.readAddress(WindbgDebuggerLocal.java:312)
at jdk.hotspot.agent/sun.jvm.hotspot.debugger.windbg.WindbgAddress.getAddressAt(WindbgAddress.java:71)
at jdk.hotspot.agent/sun.jvm.hotspot.types.basic.BasicTypeDataBase.findDynamicTypeForAddress(BasicTypeDataBase.java:238)
at jdk.hotspot.agent/sun.jvm.hotspot.runtime.VirtualBaseConstructor.instantiateWrapperFor(VirtualBaseConstructor.java:104)
at jdk.hotspot.agent/sun.jvm.hotspot.oops.Metadata.instantiateWrapperFor(Metadata.java:77)
at jdk.hotspot.agent/sun.jvm.hotspot.oops.Oop.getKlassForOopHandle(Oop.java:210)
at jdk.hotspot.agent/sun.jvm.hotspot.oops.ObjectHeap.newOop(ObjectHeap.java:181)
at jdk.hotspot.agent/sun.jvm.hotspot.oops.VMOopHandle.resolve(VMOopHandle.java:61)
at jdk.hotspot.agent/sun.jvm.hotspot.runtime.JavaThread.getThreadObj(JavaThread.java:355)
at jdk.hotspot.agent/sun.jvm.hotspot.runtime.JavaThread.getCurrentParkBlocker(JavaThread.java:407)
at jdk.hotspot.agent/sun.jvm.hotspot.runtime.DeadlockDetector.print(DeadlockDetector.java:80)
at jdk.hotspot.agent/sun.jvm.hotspot.runtime.DeadlockDetector.print(DeadlockDetector.java:39)
at jdk.hotspot.agent/sun.jvm.hotspot.tools.StackTrace.run(StackTrace.java:62)
at jdk.hotspot.agent/sun.jvm.hotspot.tools.StackTrace.run(StackTrace.java:45)
at jdk.hotspot.agent/sun.jvm.hotspot.tools.JStack.run(JStack.java:67)
at jdk.hotspot.agent/sun.jvm.hotspot.tools.Tool.startInternal(Tool.java:278)
at jdk.hotspot.agent/sun.jvm.hotspot.tools.Tool.start(Tool.java:241)
at jdk.hotspot.agent/sun.jvm.hotspot.tools.Tool.execute(Tool.java:134)
at jdk.hotspot.agent/sun.jvm.hotspot.tools.JStack.runWithArgs(JStack.java:90)
at jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.runJSTACK(SALauncher.java:302)
at jdk.hotspot.agent/sun.jvm.hotspot.SALauncher.main(SALauncher.java:500)