The test foreign.MemorySessionClose.shared_close sporadically hang for 2 threads config. With configuration for 4 sec runs per testcase this test executed 3+ hours for jdk 25-ea+13-1441.
Threads status are:
===============
# Warmup: 3 iterations, 1 s each
# Measurement: 1 iterations, 1 s each
# Timeout: 10 min per iteration
# Threads: 2 threads, will synchronize iterations
# Benchmark mode: Throughput, ops/time
# Benchmark: org.openjdk.bench.java.lang.foreign.MemorySessionClose.shared_close
# Parameters: (mode = THREADS)

# Run progress: 70.27% complete, ETA 00:32:49
# Fork: 1 of 1
WARNING: Using incubator modules: jdk.incubator.vector
openjdk version "25-ea" 2025-09-16
OpenJDK Runtime Environment (build 25-ea+13-1441)
OpenJDK 64-Bit Server VM (build 25-ea+13-1441, mixed mode, sharing)
WARNING: A terminally deprecated method in sun.misc.Unsafe has been called
WARNING: sun.misc.Unsafe::objectFieldOffset has been called by org.openjdk.jmh.util.Utils (file:/workloads/jmh_tests_tst/benchmarks.jar)
WARNING: Please consider reporting this to the maintainers of class org.openjdk.jmh.util.Utils
WARNING: sun.misc.Unsafe::objectFieldOffset will be removed in a future release
# Warmup Iteration 1: 0.059 ops/ms
# Warmup Iteration 2: 0.062 ops/ms
# Warmup Iteration 3: 0.063 ops/ms
Iteration 1: 2025-03-11 10:18:53
Full thread dump OpenJDK 64-Bit Server VM (25-ea+13-1441 mixed mode, sharing):

Threads class SMR info:
_java_thread_list=0x00007fc3f000ac50, length=20, elements={
0x00007fc4b402ca20, 0x00007fc4b415d710, 0x00007fc4b415ed40, 0x00007fc4b41606b0,
0x00007fc4b4161dd0, 0x00007fc4b4163450, 0x00007fc4b4165050, 0x00007fc4b4166840,
0x00007fc4b41eb610, 0x00007fc4b41eddf0, 0x00007fc4b42844c0, 0x00007fc4b4285180,
0x00007fc3f4000ff0, 0x00007fc3f4002310, 0x00007fc3f4003570, 0x00007fc3f4004850,
0x00007fc3f00064d0, 0x00007fc3f00076a0, 0x00007fc3f0008820, 0x00007fc3f0009a50
}

"main" #3 [3744335] prio=5 os_prio=0 cpu=277.08ms elapsed=27516.61s tid=0x00007fc4b402ca20 nid=3744335 waiting on condition [0x00007fc4b8dfe000]
   java.lang.Thread.State: WAITING (parking)
        at jdk.internal.misc.Unsafe.park(java.base@25-ea/Native Method)
        - parking to wait for <0x00000006fc400688> (a java.util.concurrent.CountDownLatch$Sync)
        at java.util.concurrent.locks.LockSupport.park(java.base@25-ea/LockSupport.java:223)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(java.base@25-ea/AbstractQueuedSynchronizer.java:789)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(java.base@25-ea/AbstractQueuedSynchronizer.java:1138)
        at java.util.concurrent.CountDownLatch.await(java.base@25-ea/CountDownLatch.java:230)
        at org.openjdk.jmh.runner.InfraControlL2.awaitWarmdownReady(InfraControl.java:252)
        at org.openjdk.jmh.runner.InfraControl.awaitWarmdownReady(InfraControl.java:40)
        at org.openjdk.jmh.runner.BenchmarkHandler.runIteration(BenchmarkHandler.java:371)
        at org.openjdk.jmh.runner.BaseRunner.runBenchmark(BaseRunner.java:283)
        at org.openjdk.jmh.runner.BaseRunner.runBenchmark(BaseRunner.java:233)
        at org.openjdk.jmh.runner.BaseRunner.doSingle(BaseRunner.java:138)
        at org.openjdk.jmh.runner.BaseRunner.runBenchmarksForked(BaseRunner.java:75)
        at org.openjdk.jmh.runner.ForkedRunner.run(ForkedRunner.java:72)
        at org.openjdk.jmh.runner.ForkedMain.main(ForkedMain.java:86)

"Reference Handler" #12 [3744344] daemon prio=10 os_prio=0 cpu=0.90ms elapsed=27516.59s tid=0x00007fc4b415d710 nid=3744344 waiting on condition [0x00007fc494efd000]
   java.lang.Thread.State: RUNNABLE
        at java.lang.ref.Reference.waitForReferencePendingList(java.base@25-ea/Native Method)
        at java.lang.ref.Reference.processPendingReferences(java.base@25-ea/Reference.java:246)
        at java.lang.ref.Reference$ReferenceHandler.run(java.base@25-ea/Reference.java:208)

"Finalizer" #13 [3744345] daemon prio=8 os_prio=0 cpu=0.11ms elapsed=27516.59s tid=0x00007fc4b415ed40 nid=3744345 in Object.wait() [0x00007fc494dfc000]
   java.lang.Thread.State: WAITING (on object monitor)
        at java.lang.Object.wait0(java.base@25-ea/Native Method)
        - waiting on <0x00000006f98000e8> (a java.lang.ref.ReferenceQueue$Lock)
        at java.lang.Object.wait(java.base@25-ea/Object.java:389)
        at java.lang.Object.wait(java.base@25-ea/Object.java:351)
        at java.lang.ref.ReferenceQueue.remove0(java.base@25-ea/ReferenceQueue.java:138)
        at java.lang.ref.ReferenceQueue.remove(java.base@25-ea/ReferenceQueue.java:229)
        - locked <0x00000006f98000e8> (a java.lang.ref.ReferenceQueue$Lock)
        at java.lang.ref.Finalizer$FinalizerThread.run(java.base@25-ea/Finalizer.java:165)

"Signal Dispatcher" #14 [3744346] daemon prio=9 os_prio=0 cpu=2.51ms elapsed=27516.59s tid=0x00007fc4b41606b0 nid=3744346 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Service Thread" #15 [3744347] daemon prio=9 os_prio=0 cpu=51.21ms elapsed=27516.59s tid=0x00007fc4b4161dd0 nid=3744347 runnable [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Monitor Deflation Thread" #16 [3744348] daemon prio=9 os_prio=0 cpu=206.10ms elapsed=27516.59s tid=0x00007fc4b4163450 nid=3744348 runnable [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"C2 CompilerThread0" #17 [3744349] daemon prio=9 os_prio=0 cpu=474.69ms elapsed=27516.59s tid=0x00007fc4b4165050 nid=3744349 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE
   No compile task

"C1 CompilerThread0" #18 [3744350] daemon prio=9 os_prio=0 cpu=436.89ms elapsed=27516.59s tid=0x00007fc4b4166840 nid=3744350 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE
   No compile task

"Notification Thread" #19 [3744351] daemon prio=9 os_prio=0 cpu=0.07ms elapsed=27516.54s tid=0x00007fc4b41eb610 nid=3744351 runnable [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Common-Cleaner" #20 [3744352] daemon prio=8 os_prio=0 cpu=5.66ms elapsed=27516.54s tid=0x00007fc4b41eddf0 nid=3744352 in Object.wait() [0x00007fc4945e4000]
   java.lang.Thread.State: TIMED_WAITING (on object monitor)
        at java.lang.Object.wait0(java.base@25-ea/Native Method)
        - waiting on <no object reference available>
        at java.lang.Object.wait(java.base@25-ea/Object.java:389)
        at java.lang.ref.ReferenceQueue.remove0(java.base@25-ea/ReferenceQueue.java:124)
        at java.lang.ref.ReferenceQueue.remove(java.base@25-ea/ReferenceQueue.java:215)
        - locked <0x00000006f98001a0> (a java.lang.ref.ReferenceQueue$Lock)
        at jdk.internal.ref.CleanerImpl.run(java.base@25-ea/CleanerImpl.java:140)
        at java.lang.Thread.runWith(java.base@25-ea/Thread.java:1460)
        at java.lang.Thread.run(java.base@25-ea/Thread.java:1447)
        at jdk.internal.misc.InnocuousThread.run(java.base@25-ea/InnocuousThread.java:148)

"org.openjdk.bench.java.lang.foreign.MemorySessionClose.shared_close-jmh-worker-1" #23 [3744354] daemon prio=5 os_prio=0 cpu=7765.15ms elapsed=27516.30s tid=0x00007fc4b42844c0 nid=3744354 waiting on condition [0x00007fc4944e3000]
   java.lang.Thread.State: RUNNABLE
        at jdk.internal.misc.ScopedMemoryAccess.closeScope0(java.base@25-ea/Native Method)
        at jdk.internal.misc.ScopedMemoryAccess.closeScope(java.base@25-ea/ScopedMemoryAccess.java:88)
        at jdk.internal.foreign.SharedSession.justClose(java.base@25-ea/SharedSession.java:92)
        at jdk.internal.foreign.MemorySessionImpl.close(java.base@25-ea/MemorySessionImpl.java:240)
        at jdk.internal.foreign.ArenaImpl.close(java.base@25-ea/ArenaImpl.java:47)
        at org.openjdk.bench.java.lang.foreign.MemorySessionClose.shared_close(MemorySessionClose.java:115)
        at org.openjdk.bench.java.lang.foreign.jmh_generated.MemorySessionClose_shared_close_jmhTest.shared_close_Throughput(MemorySessionClose_shared_close_jmhTest.java:89)
        at java.lang.invoke.DirectMethodHandle$Holder.invokeSpecial(java.base@25-ea/DirectMethodHandle$Holder)
        at java.lang.invoke.LambdaForm$MH/0x00007fc437018800.invoke(java.base@25-ea/LambdaForm$MH)
        at java.lang.invoke.LambdaForm$MH/0x00007fc437018c00.invokeExact_MT(java.base@25-ea/LambdaForm$MH)
        at jdk.internal.reflect.DirectMethodHandleAccessor.invokeImpl(java.base@25-ea/DirectMethodHandleAccessor.java:156)
        at jdk.internal.reflect.DirectMethodHandleAccessor.invoke(java.base@25-ea/DirectMethodHandleAccessor.java:104)
        at java.lang.reflect.Method.invoke(java.base@25-ea/Method.java:565)
        at org.openjdk.jmh.runner.BenchmarkHandler$BenchmarkTask.call(BenchmarkHandler.java:527)
        at org.openjdk.jmh.runner.BenchmarkHandler$BenchmarkTask.call(BenchmarkHandler.java:504)
        at java.util.concurrent.FutureTask.run(java.base@25-ea/FutureTask.java:328)
        at java.util.concurrent.Executors$RunnableAdapter.call(java.base@25-ea/Executors.java:545)
        at java.util.concurrent.FutureTask.run(java.base@25-ea/FutureTask.java:328)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@25-ea/ThreadPoolExecutor.java:1090)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@25-ea/ThreadPoolExecutor.java:614)
        at java.lang.Thread.runWith(java.base@25-ea/Thread.java:1460)
        at java.lang.Thread.run(java.base@25-ea/Thread.java:1447)

"org.openjdk.bench.java.lang.foreign.MemorySessionClose.shared_close-jmh-worker-2" #24 [3744355] daemon prio=5 os_prio=0 cpu=5785.26ms elapsed=27516.30s tid=0x00007fc4b4285180 nid=3744355 waiting on condition [0x00007fc4943e1000]
   java.lang.Thread.State: RUNNABLE
        at jdk.internal.misc.ScopedMemoryAccess.closeScope0(java.base@25-ea/Native Method)
        at jdk.internal.misc.ScopedMemoryAccess.closeScope(java.base@25-ea/ScopedMemoryAccess.java:88)
        at jdk.internal.foreign.SharedSession.justClose(java.base@25-ea/SharedSession.java:92)
        at jdk.internal.foreign.MemorySessionImpl.close(java.base@25-ea/MemorySessionImpl.java:240)
        at jdk.internal.foreign.ArenaImpl.close(java.base@25-ea/ArenaImpl.java:47)
        at org.openjdk.bench.java.lang.foreign.MemorySessionClose.shared_close(MemorySessionClose.java:115)
        at org.openjdk.bench.java.lang.foreign.jmh_generated.MemorySessionClose_shared_close_jmhTest.shared_close_thrpt_jmhStub(MemorySessionClose_shared_close_jmhTest.java:122)
        at org.openjdk.bench.java.lang.foreign.jmh_generated.MemorySessionClose_shared_close_jmhTest.shared_close_Throughput(MemorySessionClose_shared_close_jmhTest.java:84)
        at java.lang.invoke.DirectMethodHandle$Holder.invokeSpecial(java.base@25-ea/DirectMethodHandle$Holder)
        at java.lang.invoke.LambdaForm$MH/0x00007fc437018800.invoke(java.base@25-ea/LambdaForm$MH)
        at java.lang.invoke.LambdaForm$MH/0x00007fc437018c00.invokeExact_MT(java.base@25-ea/LambdaForm$MH)
        at jdk.internal.reflect.DirectMethodHandleAccessor.invokeImpl(java.base@25-ea/DirectMethodHandleAccessor.java:156)
        at jdk.internal.reflect.DirectMethodHandleAccessor.invoke(java.base@25-ea/DirectMethodHandleAccessor.java:104)
        at java.lang.reflect.Method.invoke(java.base@25-ea/Method.java:565)
        at org.openjdk.jmh.runner.BenchmarkHandler$BenchmarkTask.call(BenchmarkHandler.java:527)
        at org.openjdk.jmh.runner.BenchmarkHandler$BenchmarkTask.call(BenchmarkHandler.java:504)
        at java.util.concurrent.FutureTask.run(java.base@25-ea/FutureTask.java:328)
        at java.util.concurrent.Executors$RunnableAdapter.call(java.base@25-ea/Executors.java:545)
        at java.util.concurrent.FutureTask.run(java.base@25-ea/FutureTask.java:328)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@25-ea/ThreadPoolExecutor.java:1090)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@25-ea/ThreadPoolExecutor.java:614)
        at java.lang.Thread.runWith(java.base@25-ea/Thread.java:1460)
        at java.lang.Thread.run(java.base@25-ea/Thread.java:1447)

"Thread-6" #29 [3744356] daemon prio=5 os_prio=0 cpu=6270247.87ms elapsed=27516.29s tid=0x00007fc3f4000ff0 nid=3744356 runnable [0x00007fc4942e0000]
   java.lang.Thread.State: RUNNABLE
        at org.openjdk.bench.java.lang.foreign.MemorySessionClose.lambda$setup$0(MemorySessionClose.java:79)
        at org.openjdk.bench.java.lang.foreign.MemorySessionClose$$Lambda/0x00007fc437015288.run(Unknown Source)
        at java.lang.Thread.runWith(java.base@25-ea/Thread.java:1460)
        at java.lang.Thread.run(java.base@25-ea/Thread.java:1447)

"Thread-7" #30 [3744357] daemon prio=5 os_prio=0 cpu=6263647.97ms elapsed=27516.29s tid=0x00007fc3f4002310 nid=3744357 runnable [0x00007fc4941df000]
   java.lang.Thread.State: RUNNABLE
        at org.openjdk.bench.java.lang.foreign.MemorySessionClose.lambda$setup$0(MemorySessionClose.java:79)
        at org.openjdk.bench.java.lang.foreign.MemorySessionClose$$Lambda/0x00007fc437015288.run(Unknown Source)
        at java.lang.Thread.runWith(java.base@25-ea/Thread.java:1460)
        at java.lang.Thread.run(java.base@25-ea/Thread.java:1447)

"Thread-8" #31 [3744358] daemon prio=5 os_prio=0 cpu=7448324.78ms elapsed=27516.28s tid=0x00007fc3f4003570 nid=3744358 runnable [0x00007fc485ffd000]
   java.lang.Thread.State: RUNNABLE
        at org.openjdk.bench.java.lang.foreign.MemorySessionClose.lambda$setup$0(MemorySessionClose.java:79)
        at org.openjdk.bench.java.lang.foreign.MemorySessionClose$$Lambda/0x00007fc437015288.run(Unknown Source)
        at java.lang.Thread.runWith(java.base@25-ea/Thread.java:1460)
        at java.lang.Thread.run(java.base@25-ea/Thread.java:1447)

"Thread-9" #32 [3744359] daemon prio=5 os_prio=0 cpu=7723349.55ms elapsed=27516.27s tid=0x00007fc3f4004850 nid=3744359 runnable [0x00007fc485efc000]
   java.lang.Thread.State: RUNNABLE
        at org.openjdk.bench.java.lang.foreign.MemorySessionClose.lambda$setup$0(MemorySessionClose.java:79)
        at org.openjdk.bench.java.lang.foreign.MemorySessionClose$$Lambda/0x00007fc437015288.run(Unknown Source)
        at java.lang.Thread.runWith(java.base@25-ea/Thread.java:1460)
        at java.lang.Thread.run(java.base@25-ea/Thread.java:1447)

"Thread-2" #25 [3744360] daemon prio=5 os_prio=0 cpu=7447955.95ms elapsed=27516.27s tid=0x00007fc3f00064d0 nid=3744360 runnable [0x00007fc485dfb000]
   java.lang.Thread.State: RUNNABLE
        at org.openjdk.bench.java.lang.foreign.MemorySessionClose.lambda$setup$0(MemorySessionClose.java:79)
        at org.openjdk.bench.java.lang.foreign.MemorySessionClose$$Lambda/0x00007fc437015288.run(Unknown Source)
        at java.lang.Thread.runWith(java.base@25-ea/Thread.java:1460)
        at java.lang.Thread.run(java.base@25-ea/Thread.java:1447)

"Thread-3" #26 [3744361] daemon prio=5 os_prio=0 cpu=6597122.35ms elapsed=27516.25s tid=0x00007fc3f00076a0 nid=3744361 runnable [0x00007fc485cfa000]
   java.lang.Thread.State: RUNNABLE
        at org.openjdk.bench.java.lang.foreign.MemorySessionClose.lambda$setup$0(MemorySessionClose.java:79)
        at org.openjdk.bench.java.lang.foreign.MemorySessionClose$$Lambda/0x00007fc437015288.run(Unknown Source)
        at java.lang.Thread.runWith(java.base@25-ea/Thread.java:1460)
        at java.lang.Thread.run(java.base@25-ea/Thread.java:1447)

"Thread-4" #27 [3744362] daemon prio=5 os_prio=0 cpu=6270224.10ms elapsed=27516.25s tid=0x00007fc3f0008820 nid=3744362 runnable [0x00007fc485bf9000]
   java.lang.Thread.State: RUNNABLE
        at org.openjdk.bench.java.lang.foreign.MemorySessionClose.lambda$setup$0(MemorySessionClose.java:79)
        at org.openjdk.bench.java.lang.foreign.MemorySessionClose$$Lambda/0x00007fc437015288.run(Unknown Source)
        at java.lang.Thread.runWith(java.base@25-ea/Thread.java:1460)
        at java.lang.Thread.run(java.base@25-ea/Thread.java:1447)

"Thread-5" #28 [3744363] daemon prio=5 os_prio=0 cpu=6545329.45ms elapsed=27516.24s tid=0x00007fc3f0009a50 nid=3744363 runnable [0x00007fc485af8000]
   java.lang.Thread.State: RUNNABLE
        at org.openjdk.bench.java.lang.foreign.MemorySessionClose.lambda$setup$0(MemorySessionClose.java:79)
        at org.openjdk.bench.java.lang.foreign.MemorySessionClose$$Lambda/0x00007fc437015288.run(Unknown Source)
        at java.lang.Thread.runWith(java.base@25-ea/Thread.java:1460)
        at java.lang.Thread.run(java.base@25-ea/Thread.java:1447)

"GC Thread#1" os_prio=0 cpu=2.96ms elapsed=17617.72s tid=0x00007fc42c006f10 nid=3749460 runnable

"VM Thread" os_prio=0 cpu=341564.18ms elapsed=27516.59s tid=0x00007fc4b41550b0 nid=3744343 runnable

"VM Periodic Task Thread" os_prio=0 cpu=1015.59ms elapsed=27516.61s tid=0x00007fc4b40cd8d0 nid=3744342 waiting on condition

"G1 Service" os_prio=0 cpu=95.03ms elapsed=27516.61s tid=0x00007fc4b40bd660 nid=3744340 runnable

"G1 Refine#0" os_prio=0 cpu=0.04ms elapsed=27516.61s tid=0x00007fc4b40bc680 nid=3744339 runnable

"G1 Conc#0" os_prio=0 cpu=0.02ms elapsed=27516.61s tid=0x00007fc4b4064d70 nid=3744338 runnable

"G1 Main Marker" os_prio=0 cpu=0.04ms elapsed=27516.61s tid=0x00007fc4b4063da0 nid=3744337 runnable

"GC Thread#0" os_prio=0 cpu=3.04ms elapsed=27516.61s tid=0x00007fc4b4053760 nid=3744336 runnable

JNI global refs: 13, weak refs: 0

Heap
 garbage-first heap total reserved 6291456K, committed 2101248K, used 171724K [0x0000000680000000, 0x0000000800000000)
  region size 4096K, 42 young (172032K), 1 survivors (4096K)
 Metaspace used 3750K, committed 3840K, reserved 1114112K
  class space used 328K, committed 384K, reserved 1048576K