8369255: Assess and remedy any unsafe usage of the Semaphores used by JFR

[mgronlun]

Greetings,

Please help review this change set that prevents a race in the shutdown of the VM, where the CRT is destroyed while threads might still be running JFR code. Please see the JIRA issue for an explanation.

Testing: jdk_jfr, tier 1 - 3

Thanks
Markus

---

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-8369255: Assess and remedy any unsafe usage of the Semaphores used by JFR (Bug - P3)

Reviewers

• Erik Gahlin (@egahlin - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/27722/head:pull/27722
$ git checkout pull/27722

Update a local copy of the PR:
$ git checkout pull/27722
$ git pull https://git.openjdk.org/jdk.git pull/27722/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 27722

View PR using the GUI difftool:
$ git pr show -t 27722

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/27722.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back mgronlun! 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]

@mgronlun 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:

8369255: Assess and remedy any unsafe usage of the Semaphores used by JFR

Reviewed-by: egahlin

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 60 new commits pushed to the master branch:

• cd1ce58: 8369454: Verify checksums of downloaded source bundles when creating devkit
• 1cdd241: 8369420: Parallel: Use multiple workers for class unloading
• b73228b: 8369450: [Ubuntu 25.10] openjdk fails to build due to rust-coreutils date
• ... and 57 more: https://git.openjdk.org/jdk/compare/aed9485bbb1d93063e5e5f60ed84bfb36053bdd1...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]

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

• hotspot-jfr

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

• 00: Full (78037268)

[mgronlun]

/integrate

[openjdk]

Going to push as commit 62fa971.
Since your change was applied there have been 88 commits pushed to the master branch:

• 0db4702: 8368877: Generate Jextract bindings for Kqueue
• 28460ca: 8368897: RISC-V: Cleanup RV_EXT_FEATURE_FLAGS & RV_NON_EXT_FEATURE_FLAGS
• 0af959a: 8369560: Slowdebug build without CDS fails
• ... and 85 more: https://git.openjdk.org/jdk/compare/aed9485bbb1d93063e5e5f60ed84bfb36053bdd1...master

Your commit was automatically rebased without conflicts.

[openjdk]

@mgronlun Pushed as commit 62fa971.

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