8331735: UpcallLinker::on_exit races with GC when copying frame anchor

[gnu-andrew]

Partial backport of a fix for a race condition in code adapted from JavaCallWrapper for the FFM API. This is more visible in 22 and later, where FFM is fully supported and the OpenType implementation using HarfBuzz has been ported to use it.

However, the copy in the native state seems to have been introduced as far back as JDK-8269240 in 17 when the JavaCallWrapper code was ported to what was then universalUpcallHandler.cpp. That fix to ::on_exit is included here.

The other hunk in the 24 and 21u versions is omitted as the ::on_entry method has not been modified by JDK-8272526 which is what moved the thread exception handling to native code.

---

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
• JDK-8286875 needs maintainer approval
• JDK-8331735 needs maintainer approval

Issues

• JDK-8331735: UpcallLinker::on_exit races with GC when copying frame anchor (Bug - P3 - Approved)
• JDK-8286875: ProgrammableUpcallHandler::on_entry/on_exit access thread fields from native (Bug - P4 - Approved)

Reviewers

• Martin Balao (@martinuy - Reviewer)

Reviewing

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[bridgekeeper]

👋 Welcome back andrew! 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]

@gnu-andrew 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:

8331735: UpcallLinker::on_exit races with GC when copying frame anchor
8286875: ProgrammableUpcallHandler::on_entry/on_exit access thread fields from native

Reviewed-by: mbalao

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 1 new commit pushed to the master branch:

• 729b0c7: 8352649: [17u] guarantee(is_result_safe || is_in_asgct()) failed inside AsyncGetCallTrace

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[openjdk]

This backport pull request has now been updated with issues from the original commit.

[gnu-andrew]

/issue remove 8343144

[openjdk]

@gnu-andrew
Removing additional issue from issue list: 8343144.

[mlbridge]

Webrevs

• 00: Full (8cc6eb6e)

[martinuy]

Thanks for contributing this backport. Looks good to me.

[openjdk]

⚠️ @gnu-andrew This change is now ready for you to apply for maintainer approval. This can be done directly in each associated issue or by using the /approval command.

[gnu-andrew]

Thanks Martin.

/approval request Partial backport of a fix for a race condition in the FFM API. Can lead to crashes when the FFM code manipulates a frame anchor in native mode, which the GC does not expect to happen. Fix is to move the frame anchor copying to Java mode, where the GC will wait for the thread to get to a safepoint. Risk to other code is low as the UpcallLinker is only used by FFM, which is in incubation in 17u.

[openjdk]

@gnu-andrew
8331735: The approval request has been created successfully.
8286875: The approval request has been created successfully.

[gnu-andrew]

/approval request Partial backport of a fix for a race condition in the FFM API. Can lead to crashes when the FFM code manipulates a frame anchor in native mode, which the GC does not expect to happen. Fix is to move the frame anchor copying to Java mode, where the GC will wait for the thread to get to a safepoint. Risk to other code is low as the UpcallLinker is only used by FFM, which is in incubation in 17u. Patch has been reviewed by Martin Balao.

[openjdk]

@gnu-andrew
8331735: The approval request has been updated successfully.
8286875: The approval request has been updated successfully.

[gnu-andrew]

/integrate

[openjdk]

Going to push as commit 8ea7310.
Since your change was applied there have been 23 commits pushed to the master branch:

• ac00cd2: 8329261: G1: interpreter post-barrier x86 code asserts index size of wrong buffer
• 9ef3fb4: 8352716: (tz) Update Timezone Data to 2025b
• 7a29de5: 8271419: Refactor test code for modifying CDS archive contents
• ... and 20 more: https://git.openjdk.org/jdk17u-dev/compare/bb103d7d0914f90e85eb5f87831ffef1de536072...master

Your commit was automatically rebased without conflicts.

[openjdk]

@gnu-andrew Pushed as commit 8ea7310.

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