8360288: Shenandoah crash at size_given_klass in op_degenerated

[earthling-amzn]

Not clean, but not difficult to resolve.

---

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-8360288 needs maintainer approval

Issue

• JDK-8360288: Shenandoah crash at size_given_klass in op_degenerated (Bug - P3 - Requested)

Reviewers

• Paul Hohensee (@phohensee - Reviewer)

Reviewing

Using git

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$ git fetch https://git.openjdk.org/jdk21u-dev.git pull/2281/head:pull/2281
$ git checkout pull/2281

Update a local copy of the PR:
$ git checkout pull/2281
$ git pull https://git.openjdk.org/jdk21u-dev.git pull/2281/head

Using Skara CLI tools

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$ git pr checkout 2281

View PR using the GUI difftool:
$ git pr show -t 2281

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk21u-dev/pull/2281.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back wkemper! 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]

❗ This change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.

[openjdk]

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

[mlbridge]

Webrevs

• 00: Full (068ef698)

[openjdk]

⚠️ @earthling-amzn 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.

[earthling-amzn]

/approval request This change fixes a crash when Shenandoah unloads the class for an unmarked humongous object. The change only affects Shenandoah. We've tested this with jtreg tiers 1-3 with Shenandoah enabled. We have also tested this on various benchmarks: dacapo, specjvm, specjbb, extremem and others. We have also been running this patch in production services for the past month.

[openjdk]

@earthling-amzn
8360288: The approval request has been created successfully.