8321216: SerialGC attempts to access the card table beyond the end of the heap during card table scan

[tschatzl]

Hi all,

please review this fix to CardTableRS::find_first_clean_card where when iterating through the object at the very end of the heap Serial GC accesses the card table beyond the allocated memory, which fails with an assert.

The fix is to allow retrieving addresses for cards beyond the card table using a special addr_for_raw method.

In discussions with @albertnetymk , the initial version to add a check whether the current scan cursor is already at or beyond the end of the area to find clean cards for using an extra, somewhat superfluous parameter has been rejected as a bit confusing (the first commit).

Testing: failing test case, gha

Thanks,
Thomas

---

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Issue

• JDK-8321216: SerialGC attempts to access the card table beyond the end of the heap during card table scan (Bug - P1)

Reviewers

• Albert Mingkun Yang (@albertnetymk - Reviewer)
• Ivan Walulya (@walulyai - Reviewer)

Contributors

• Albert Mingkun Yang <ayang@openjdk.org>

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[tschatzl]

/contributor add @albertnetymk

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@tschatzl
Contributor Albert Mingkun Yang <ayang@openjdk.org> successfully added.

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

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

8321216: SerialGC attempts to access the card table beyond the end of the heap during card table scan

Co-authored-by: Albert Mingkun Yang <ayang@openjdk.org>
Reviewed-by: ayang, iwalulya

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At the time when this comment was updated there had been 4 new commits pushed to the master branch:

• 4fbf22b: 8320652: ThreadInfo.isInNative needs to be updated to say what executing native code means
• 672f373: 8321163: [test] OutputAnalyzer.getExitValue() unnecessarily logs even when process has already completed
• 30817b7: 8317809: Insertion of free code blobs into code cache can be very slow during class unloading
• a56286f: 8321269: Require platforms to define DEFAULT_CACHE_LINE_SIZE

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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.

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[tschatzl]

Thanks @albertnetymk @walulyai for your reviews.
I'll integrate early because it makes a mess of the CI pipeline, and the change seems obvious enough.

/integrate

[openjdk]

Going to push as commit 800f347.
Since your change was applied there have been 6 commits pushed to the master branch:

• a1fe16b: 8321300: Cleanup TestHFA
• 5b02188: 8321105: Enable UseCryptoPmullForCRC32 for Neoverse V2
• 4fbf22b: 8320652: ThreadInfo.isInNative needs to be updated to say what executing native code means
• 672f373: 8321163: [test] OutputAnalyzer.getExitValue() unnecessarily logs even when process has already completed
• 30817b7: 8317809: Insertion of free code blobs into code cache can be very slow during class unloading
• a56286f: 8321269: Require platforms to define DEFAULT_CACHE_LINE_SIZE

Your commit was automatically rebased without conflicts.

[openjdk]

@tschatzl Pushed as commit 800f347.

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