This is an umbrella bug for hangs related to jdk.jfr.internal.jdk.jfr.internal.JVM.flush()

Typical thread dump looks like this:

"MainThread" #34 [1203715] prio=5 os_prio=0 cpu=1856.25ms elapsed=1200.19s tid=0x0000ffffac4753f0 nid=1203715 waiting for monitor entry [0x0000ffff5c80d000]
   java.lang.Thread.State: BLOCKED (on object monitor)
Thread: 0x0000ffffac4753f0 [0x125e03] State: _at_safepoint _at_poll_safepoint 0
   JavaThread state: _thread_blocked
    at jdk.jfr.internal.MetadataRepository.setSettings(jdk.jfr@24/MetadataRepository.java:243)
    - waiting to lock <0x000000011f9499d8> (a jdk.jfr.internal.MetadataRepository)
    at jdk.jfr.internal.PlatformRecorder.updateSettingsButIgnoreRecording(jdk.jfr@24/PlatformRecorder.java:393)
    at jdk.jfr.internal.PlatformRecorder.updateSettings(jdk.jfr@24/PlatformRecorder.java:382)
    at jdk.jfr.internal.PlatformRecorder.start(jdk.jfr@24/PlatformRecorder.java:252)
    - locked <0x000000011f80db28> (a jdk.jfr.internal.PlatformRecorder)
    at jdk.jfr.internal.PlatformRecording.start(jdk.jfr@24/PlatformRecording.java:127)
    - locked <0x000000011f80db28> (a jdk.jfr.internal.PlatformRecorder)
    at jdk.jfr.Recording.start(jdk.jfr@24/Recording.java:177)
    at jdk.jfr.tool.TestAssemble.main(TestAssemble.java:66)
    at java.lang.invoke.LambdaForm$DMH/0x0000ffff4c4083e0.invokeStatic(java.base@24/LambdaForm$DMH)
    at java.lang.invoke.LambdaForm$MH/0x0000ffff4c40ac10.invoke(java.base@24/LambdaForm$MH)
    at java.lang.invoke.Invokers$Holder.invokeExact_MT(java.base@24/Invokers$Holder)
    at jdk.internal.reflect.DirectMethodHandleAccessor.invokeImpl(java.base@24/DirectMethodHandleAccessor.java:155)
    at jdk.internal.reflect.DirectMethodHandleAccessor.invoke(java.base@24/DirectMethodHandleAccessor.java:104)
    at java.lang.reflect.Method.invoke(java.base@24/Method.java:573)
    at com.sun.javatest.regtest.agent.MainWrapper$MainTask.run(MainWrapper.java:138)
    at java.lang.Thread.runWith(java.base@24/Thread.java:1589)
    at java.lang.Thread.run(java.base@24/Thread.java:1576)

"JFR Recorder Thread" #35 [1203785] daemon prio=5 os_prio=0 cpu=3.19ms elapsed=1199.91s tid=0x0000fffefcf6d7e0 nid=1203785 runnable [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE
Thread: 0x0000fffefcf6d7e0 [0x125e49] State: _at_safepoint _at_poll_safepoint 0
   JavaThread state: _thread_in_native

"JFR Periodic Tasks" #36 [1204201] daemon prio=5 os_prio=0 cpu=20.92ms elapsed=1198.94s tid=0x0000fffefd209ec0 nid=1204201 runnable [0x0000ffff5c60e000]
   java.lang.Thread.State: RUNNABLE
Thread: 0x0000fffefd209ec0 [0x125fe9] State: _at_safepoint _at_poll_safepoint 0
   JavaThread state: _thread_blocked
    at jdk.jfr.internal.JVM.flush(jdk.jfr@24/Native Method)
    at jdk.jfr.internal.MetadataRepository.flush(jdk.jfr@24/MetadataRepository.java:382)
    - locked <0x000000011f9499d8> (a jdk.jfr.internal.MetadataRepository)
    at jdk.jfr.internal.periodic.FlushTask.execute(jdk.jfr@24/FlushTask.java:47)
    at jdk.jfr.internal.periodic.PeriodicTask.run(jdk.jfr@24/PeriodicTask.java:128)
    at jdk.jfr.internal.periodic.PeriodicEvents.doPeriodic(jdk.jfr@24/PeriodicEvents.java:175)
    at jdk.jfr.internal.PlatformRecorder.periodicTask(jdk.jfr@24/PlatformRecorder.java:518)
    at jdk.jfr.internal.PlatformRecorder.lambda$startDiskMonitor$0(jdk.jfr@24/PlatformRecorder.java:444)
    at jdk.jfr.internal.PlatformRecorder$$Lambda/0x000003f001076b08.run(jdk.jfr@24/Unknown Source)
    at java.lang.Thread.runWith(java.base@24/Thread.java:1589)
    at java.lang.Thread.run(java.base@24/Thread.java:1576)