The following test failed in the JDK20 CI:

java/lang/Thread/virtual/stress/Skynet.java#id1

Here's a snippet from the log file:

#section:main
----------messages:(8/440)----------
command: main -XX:+UnlockDiagnosticVMOptions -XX:+ZVerifyViews -XX:ZCollectionInterval=0.01 Skynet
reason: User specified action: run main/othervm/timeout=300 -XX:+UnlockDiagnosticVMOptions -XX:+ZVerifyViews -XX:ZCollectionInterval=0.01 Skynet
started: Thu Dec 15 22:08:55 GMT 2022
Mode: othervm [/othervm specified]
Timeout information:
--- Timeout information end.
finished: Thu Dec 15 23:02:39 GMT 2022
elapsed time (seconds): 3223.784
----------configuration:(0/0)----------
----------System.out:(1362/89123)----------
Result: 499999500000 in 35984 ms
Timeout refired 3000 times
Exception in VM (AttachListener::init) :
java.lang.OutOfMemoryError: Java heap space
Exception in VM (AttachListener::init) :
java.lang.OutOfMemoryError: Java heap space
Exception in VM (AttachListener::init) :
java.lang.OutOfMemoryError: Java heap space
Exception in VM (AttachListener::init) :
java.lang.OutOfMemoryError: Java heap space
Exception in VM (AttachListener::init) :
java.lang.OutOfMemoryError: Java heap space
Exception in VM (AttachListener::init) :
java.lang.OutOfMemoryError: Java heap space
Exception in VM (AttachListener::init) :
java.lang.OutOfMemoryError: Java heap space
Exception in VM (AttachListener::init) :
java.lang.OutOfMemoryError: Java heap space
Exception in VM (AttachListener::init) :
java.lang.OutOfMemoryError: Java heap space
Exception in VM (AttachListener::init) :
java.lang.OutOfMemoryError: Java heap space
Exception in VM (AttachListener::init) :
java.lang.OutOfMemoryError: Java heap space
2022-12-15 23:00:15
Full thread dump Java HotSpot(TM) 64-Bit Server VM (20-ea+28-2221 compiled mode, sharing):

Threads class SMR info:
_java_thread_list=0x00007fec2cd32370, length=13, elements={
0x00007fec2d809610, 0x00007fec2d010210, 0x00007fec2f00a410, 0x00007fec2d82b610,
0x00007fec2f00b010, 0x00007fec2d81fe10, 0x00007fec2d82c610, 0x00007fec2d196410,
0x00007fec2e8a5610, 0x00007fec2d01c410, 0x00007fec2d828810, 0x00007fec2d829010,
0x00007fec2e812410
}
_to_delete_list=0x00007fec2ccd9610, length=14, elements={
0x00007fec2d809610, 0x00007fec2d010210, 0x00007fec2f00a410, 0x00007fec2d82b610,
0x00007fec2f00b010, 0x00007fec2d81fe10, 0x00007fec2d82c610, 0x00007fec2d196410,
0x00007fec2e8a5610, 0x00007fec2d01c410, 0x00007fec2d828810, 0x00007fec2d829010,
0x00007fec2e812410, 0x00007fec3200fa10
}

<snip>

"VM Periodic Task Thread" os_prio=31 cpu=529.46ms elapsed=3073.43s tid=0x00007fec2ff33210 nid=39943 waiting on condition

JNI global refs: 9, weak refs: 0

Heap
 ZHeap used 768M, capacity 768M, max capacity 768M
 Metaspace used 2951K, committed 3136K, reserved 1114112K
  class space used 94K, committed 192K, reserved 1048576K

----------System.err:(23/2079)----------
Exception in thread "" java.lang.AssertionError
at java.base/java.lang.VirtualThread.park(VirtualThread.java:571)
at java.base/java.lang.System$2.parkVirtualThread(System.java:2630)
at java.base/jdk.internal.misc.VirtualThreads.park(VirtualThreads.java:54)
at java.base/java.util.concurrent.locks.LockSupport.park(LockSupport.java:369)
at java.base/java.util.concurrent.SynchronousQueue$TransferStack$SNode.block(SynchronousQueue.java:288)
at java.base/java.util.concurrent.ForkJoinPool.unmanagedBlock(ForkJoinPool.java:3780)
at java.base/java.util.concurrent.ForkJoinPool.managedBlock(ForkJoinPool.java:3725)
at java.base/java.util.concurrent.SynchronousQueue$TransferStack.transfer(SynchronousQueue.java:397)
at java.base/java.util.concurrent.SynchronousQueue.put(SynchronousQueue.java:839)
at Skynet$Channel.send(Skynet.java:94)
at Skynet.skynet(Skynet.java:68)
at Skynet.lambda$skynet$1(Skynet.java:73)
at java.base/java.lang.VirtualThread.run(VirtualThread.java:305)
at java.base/java.lang.VirtualThread$VThreadContinuation.lambda$new$0(VirtualThread.java:177)
at java.base/jdk.internal.vm.Continuation.enter0(Continuation.java:327)
at java.base/jdk.internal.vm.Continuation.enter(Continuation.java:320)
Exception in thread "" java.lang.AssertionError
Exception in thread "" Exception in thread "" Exception in thread "" Exception in thread "" Exception in thread "" Exception in thread "" Exception in thread "" java.lang.OutOfMemoryError: Java heap space
Exception in thread "" Exception in thread "" java.lang.AssertionError
Exception in thread "" Exception in thread "" Exception in thread "" java.lang.OutOfMemoryError: Java heap space
Exception in thread "" Exception in thread "" Exception in thread "" Exception in thread "" Exception in thread "" Exception in thread "" Exception in thread "" Exception in thread "" java.lang.AssertionError
Exception in thread "" Exception in thread "" Exception in thread "" Exception in thread "" Exception in thread "" Exception in thread "" Exception in thread "" Exception in thread "" Exception in thread ""
----------rerun:(45/6511)*----------

<snip>

result: Error. Program `/System/Volumes/Data/mesos/work_dir/jib-master/install/jdk-20+28-2221/macosx-x64-debug.jdk/jdk-20/fastdebug/bin/java' timed out (timeout set to 3000000ms, elapsed time including timeout handling was 3223773ms).