The following test timed out in the Valhalla CI:

serviceability/jvmti/vthread/VThreadTest/VThreadTest.java

Here's a snippet from the log file:

#section:main
----------messages:(11/461)----------
command: main -agentlib:VThreadTest VThreadTest
reason: User specified action: run main/othervm/native -agentlib:VThreadTest VThreadTest
started: Tue Mar 03 10:23:47.580 UTC 2026
Mode: othervm [/othervm specified]
Process id: 3155605
Timeout information:
[10:31:47.591] starting timeout handler action(s)
[10:32:41.080] timeout handler action(s) completed
--- Timeout information end.
finished: Tue Mar 03 10:32:41.082 UTC 2026
elapsed time (seconds): 533.502
----------configuration:(0/0)----------
----------System.out:(747/40899)----------
Agent_OnLoad started
Agent_OnLoad finished
processVThreadEvent: event: VirtualThreadStart, thread: VThread-Consumer

#### VirtualThreadStart event: thread: VThread-Consumer, vthread: 0x7ff224001120

test_GetVirtualThread: event: VirtualThreadStart
JVMTI GetVirtualThread with nullptr thread (current) returned non-null vthread as expected
JVMTI GetVirtualThread with good thread returned non-null vthread as expected

<snip>

JVMTI Stack Trace: frame count: 15
 0: java/lang/VirtualThread: yieldContinuation()Z
 1: java/lang/VirtualThread: park()V
 2: java/lang/System$1: parkVirtualThread()V
 3: java/util/concurrent/locks/LockSupport: park()V
 4: java/util/concurrent/LinkedTransferQueue$DualNode: await(Ljava/lang/Object;JLjava/lang/Object;Z)Ljava/lang/Object;
 5: java/util/concurrent/SynchronousQueue$Transferer: xferLifo(Ljava/lang/Object;J)Ljava/lang/Object;
 6: java/util/concurrent/SynchronousQueue: xfer(Ljava/lang/Object;J)Ljava/lang/Object;
 7: java/util/concurrent/SynchronousQueue: take()Ljava/lang/Object;
 8: VThreadTest: lambda$static$1()V
 9: VThreadTest$$Lambda.0x0000000008041800: run()V
10: java/lang/Thread: runWith(Ljava/lang/Object;Ljava/lang/Runnable;)V
11: java/lang/VirtualThread: run(Ljava/lang/Runnable;)V
12: java/lang/VirtualThread$VThreadContinuation$1: run()V
13: jdk/internal/vm/Continuation: enter0()V
14: jdk/internal/vm/Continuation: enter(Ljdk/internal/vm/Continuation;Z)V

JVMTI GetLocalInstance succeed for carrier thread top frame Continuation.run()
processVThreadEvent: event: VirtualThreadEnd, thread: VThread-Producer

#### VirtualThreadEnd event: thread: VThread-Producer, vthread: 0x7ff1ec001120
[10:31:47.591] Timeout signalled after 480 seconds
----------System.err:(5/715)----------
WARNING: A restricted method in java.lang.System has been called
WARNING: java.lang.System::loadLibrary has been called by VThreadTest in an unnamed module (file:/opt/mach5/mesos/work_dir/slaves/da1065b5-7b94-4f0d-85e9-a3a252b9a32e-S145012/frameworks/1735e8a2-a1db-478c-8104-60c8b0af87dd-0196/executors/75cf986e-ee17-4875-b9ee-e25398bea22e/runs/07bd7595-e928-456e-804d-f569f9cac195/testoutput/test-support/jtreg_open_test_hotspot_jtreg_tier1_serviceability/classes/5/serviceability/jvmti/vthread/VThreadTest/VThreadTest.d/)
WARNING: Use --enable-native-access=ALL-UNNAMED to avoid a warning for callers in this module
WARNING: Restricted methods will be blocked in a future release unless native access is enabled

----------rerun:(41/6851)*----------

<snip>

result: Error. '/opt/mach5/mesos/work_dir/jib-master/install/jdk-27-valhalla+1-186/linux-x64-debug.jdk/jdk-27/fastdebug/bin/java' timed out after 480000 ms (elapsed time including timeout handling 533492 ms); but completed after timeout - suppressed status: "Failed. Unexpected exit from test [exit code: 134]"

Since this is an intermittent Tier1 failure, I'm starting this issue off at P3.
Please note that this initial sighting is with the --enable-preview option.