8362282: runtime/logging/StressAsyncUL.java failed with exitValue = 134

[caspernorrbin]

Hi everyone,

During AsyncLogWriter initialization we previously published the global AsyncLogWriter _instance before waiting for existing synchronous logging activity to finish and before starting the async consumer thread. As soon as _instance became visible, is_enqueue_allowed() allowed new log calls to switch to the async path. Those calls bumped LogOutputList's counters while initialize() was waiting for wait_until_no_readers() to observe no active readers. At the same time, because the consumer thread wasn’t yet running, producers could end up waiting for a consumer that didn’t exist. In rare timing, this created a circular wait that manifested as intermittent lock-ups in StressAsyncUL.java.

The initialization order is changed so that we do not make the async writer visible until after all pre-existing synchronous logging has completed. Concretely, initialize() now:

1. waits for each LogTagSet to report no readers, ensuring synchronous logging is done,
2. publishes _instance with a release store so readers observe a fully initialized writer, and
3. immediately starts the async logging thread.

With this ordering, new async producers cannot keep the counters inflated while initialization is waiting. Any messages produced in the brief window between publishing _instance and the thread's first run are safely buffered and then consumed as soon as the thread starts.

Testing:

• Oracle tiers 1-3
• Repeated runs of StressAsyncUL.java with no observed lock-ups

---

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-8362282: runtime/logging/StressAsyncUL.java failed with exitValue = 134 (Bug - P3)

Reviewers

• David Holmes (@dholmes-ora - Reviewer) Review applies to d8dd6162
• Johan Sjölen (@jdksjolen - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/27169/head:pull/27169
$ git checkout pull/27169

Update a local copy of the PR:
$ git checkout pull/27169
$ git pull https://git.openjdk.org/jdk.git pull/27169/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 27169

View PR using the GUI difftool:
$ git pr show -t 27169

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/27169.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back cnorrbin! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

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

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

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

8362282: runtime/logging/StressAsyncUL.java failed with exitValue = 134

Reviewed-by: jsjolen, dholmes

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 20 new commits pushed to the master branch:

• 9e3fa32: 8349288: runtime/os/windows/TestAvailableProcessors.java fails on localized Windows platform
• b7b01d6: 8366984: Remove delay slot support
• 2705e88: 8366764: Deproblemlist java/awt/ScrollPane/ScrollPositionTest.java
• ... and 17 more: https://git.openjdk.org/jdk/compare/e16c510071f84bdbd57a8b2d3810c484c314ccf9...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]

@caspernorrbin The following label will be automatically applied to this pull request:

• hotspot-runtime

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing list. If you would like to change these labels, use the /label pull request command.

[mlbridge]

Webrevs

• 01: Full - Incremental (8e42198b)
• 00: Full (d8dd6162)

[dholmes-ora]

Fix looks good. One minor nit. Thanks.

[dholmes-ora]

Suggested change

	// Then, start the AsyncLog Thread; It exclusively takes over all logging I/O.
	// Then we start the AsyncLog Thread and it exclusively takes over all logging I/O.

[caspernorrbin]

Changed wording to this in 8e42198.

[jdksjolen]

Seems correct

[caspernorrbin]

Thank you for the quick reviews!

/integrate

[openjdk]

Going to push as commit c968a67.
Since your change was applied there have been 29 commits pushed to the master branch:

• 385c132: 8367240: Parallel: Refactor PSScavengeCLDClosure
• 46ae1ee: 8277444: Data race between JvmtiClassFileReconstituter::copy_bytecodes and class linking
• 703d930: 8366980: TestTransparentHugePagesHeap.java fails when run with -UseCompressedOops
• ... and 26 more: https://git.openjdk.org/jdk/compare/e16c510071f84bdbd57a8b2d3810c484c314ccf9...master

Your commit was automatically rebased without conflicts.

[openjdk]

@caspernorrbin Pushed as commit c968a67.

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