8371502: serviceability/jvmti/vthread/ThreadListStackTracesTest/ThreadListStackTracesTest.java failing

[sspitsyn]

This fixes the test which is unreliable and fails intermittently from time to time.
The test was failing in the method checkReentrantLock() when comparing the expected state with result from vt.getState(). The issue is that the call to ThreadListStackTracesTest.reentrantLock.lock() in a ReentrantLockTestTask can reach waiting state on some class loading but not on the ReentrantLock. Please see the first comment for test sources details.
The fix is to add a big enough sleep before call to the checkStates().

Testing:

• submitted about thousands of mach5 runs of the ThreadListStackTracesTest test runs before and after the fix
• TBD: submit mach5 tiers 1-3 to be completely safe

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8371502: serviceability/jvmti/vthread/ThreadListStackTracesTest/ThreadListStackTracesTest.java failing (Bug - P4)

Reviewers

• Leonid Mesnik (@lmesnik - Reviewer)
• Alex Menkov (@alexmenkov - Reviewer)

Reviewing

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[openjdk]

@sspitsyn This change now passes all automated pre-integration checks.

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After integration, the commit message for the final commit will be:

8371502: serviceability/jvmti/vthread/ThreadListStackTracesTest/ThreadListStackTracesTest.java failing

Reviewed-by: lmesnik, amenkov

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 75 new commits pushed to the master branch:

• ae85d89: 8373389: Two jdk/incubator/vector/ tests fails after JDK-8371446
• 66d7b0c: 8371657: [macosx] Programmatically selecting/deselecting List item triggers an ItemEvent
• 431dcf8: 8368702: [macosx] Printing text with composite fonts loses font transform
• ... and 72 more: https://git.openjdk.org/jdk/compare/15f25389435288881644f7aeab48fd2eae410999...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[openjdk]

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• serviceability

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[mlbridge]

Webrevs

• 02: Full - Incremental (a9c4752f)
• 01: Full - Incremental (38ad6eec)
• 00: Full (944164a7)

[sspitsyn]

The most relevant test fragments are below:

    private static void checkReentrantLock() throws InterruptedException {
        final Thread.State expState = Thread.State.WAITING;
        reentrantLock.lock();
        String name = "ReentrantLockTestTask";
        TestTask task = new ReentrantLockTestTask();
        Thread vt = Thread.ofVirtual().name(name).start(task);
        task.ensureReady(vt, expState);
        checkStates(vt, expState); <== intermittently fails inside this call !!!
    } 

   private static void checkStates(Thread vt, Thread.State expState) {
        int singleState = getStateSingle(vt);
        int multiState = getStateMultiple(vt, Thread.currentThread());
        int jvmtiExpState = (expState == Thread.State.WAITING) ?
                            JVMTI_THREAD_STATE_WAITING :
                            JVMTI_THREAD_STATE_BLOCKED_ON_MONITOR_ENTER;

        System.out.printf("State: expected: %s single: %x multi: %x\n",
                          vt.getState(), singleState, multiState); <== printed state values !!!

        if (vt.getState() != expState) {         <== this comparison failed!!!
            failed("Java thread state is wrong");    <== Exception is thrown here!!!
        }
        . . .

class ReentrantLockTestTask extends TestTask {
    public void run() {
        log("grabbing reentrantLock");
        threadReady = true;
        ThreadListStackTracesTest.reentrantLock.lock(); <== May have waiting state in some class loading!
        log("grabbed reentrantLock");
    }
}

[lmesnik]

Looks good. Thank you for explanation.

[sspitsyn]

Leonid, thank you for review and suggestions!

[sspitsyn]

Thank you for review, Alex!

[sspitsyn]

/integrate

[openjdk]

Going to push as commit c46bed7.
Since your change was applied there have been 75 commits pushed to the master branch:

• ae85d89: 8373389: Two jdk/incubator/vector/ tests fails after JDK-8371446
• 66d7b0c: 8371657: [macosx] Programmatically selecting/deselecting List item triggers an ItemEvent
• 431dcf8: 8368702: [macosx] Printing text with composite fonts loses font transform
• ... and 72 more: https://git.openjdk.org/jdk/compare/15f25389435288881644f7aeab48fd2eae410999...master

Your commit was automatically rebased without conflicts.

[openjdk]

@sspitsyn Pushed as commit c46bed7.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

[sspitsyn]

/backport :jdk26

[openjdk]

@sspitsyn the backport was successfully created on the branch backport-sspitsyn-c46bed72-jdk26 in my personal fork of openjdk/jdk. To create a pull request with this backport targeting openjdk/jdk:jdk26, just click the following link:

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Hi all,

This pull request contains a backport of commit c46bed72 from the openjdk/jdk repository.

The commit being backported was authored by Serguei Spitsyn on 12 Dec 2025 and was reviewed by Leonid Mesnik and Alex Menkov.

Thanks!

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