8373116: Genshen: arraycopy_work should be always done for arrays in old gen during young concurrent marking

[pengxiaolong]

Hi all,

This pull request contains a clean backport of commit c9ab330b from the openjdk/jdk repository.

The commit being backported was authored by Xiaolong Peng on 9 Dec 2025 and was reviewed by William Kemper and Kelvin Nilsen.

It is a necessary bug fix to address the crash caused by recently change to arraycopy barrier.

Thanks!

---

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

Issues

• JDK-8373116: Genshen: arraycopy_work should be always done for arrays in old gen during young concurrent marking (Bug - P3)
• JDK-8372498: [genshen] gc/TestAllocHumongousFragment.java#generational causes intermittent SIGSEGV crashes (Bug - P3)

Reviewers

• Aleksey Shipilev (@shipilev - Reviewer)
• William Kemper (@earthling-amzn - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/28751/head:pull/28751
$ git checkout pull/28751

Update a local copy of the PR:
$ git checkout pull/28751
$ git pull https://git.openjdk.org/jdk.git pull/28751/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 28751

View PR using the GUI difftool:
$ git pr show -t 28751

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/28751.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back xpeng! A progress list of the required criteria for merging this PR into jdk26 will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

@pengxiaolong 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:

8373116: Genshen: arraycopy_work should be always done for arrays in old gen during young concurrent marking
8372498: [genshen] gc/TestAllocHumongousFragment.java#generational causes intermittent SIGSEGV crashes

Reviewed-by: shade, wkemper

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 no new commits pushed to the jdk26 branch. If another commit should be pushed before you perform the /integrate command, your PR will be automatically rebased. If you prefer to avoid any potential automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the jdk26 branch, type /integrate in a new comment.

[openjdk]

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

[pengxiaolong]

/issue add 8372498

[openjdk]

@pengxiaolong
Updating description of additional solved issue: 8372498: [genshen] gc/TestAllocHumongousFragment.java#generational causes intermittent SIGSEGV crashes.

[openjdk]

@pengxiaolong The following labels will be automatically applied to this pull request:

• hotspot-gc
• shenandoah

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

[mlbridge]

Webrevs

• 00: Full (bce757f3)

[pengxiaolong]

Thank you all!

/integrate

[openjdk]

Going to push as commit 15b5789.

[openjdk]

@pengxiaolong Pushed as commit 15b5789.

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