8351921: G1: Pinned regions with pinned objects only reachable by native code crash VM

[tschatzl]

Hi all,

please review this fix for a crash in G1 where it tries to reclaim a pinned region that does not have any reference visible to the VM any more and there are no other reachable pinnable objects in the same region. This can happen e.g. when JNI code is the only holder for a reference.

This has been reported this in a real application, but the attached test case (that uses WhiteBox to simulate a lone pinnable object in a region where the GC does not have a reference any more) shows the principle as well.

The solution involves unconditionally adding pinned regions in the collection set to the set of evacuation failed regions, instead of only doing that when G1 first encounters a reachable pinnable object in that pinned region.

Testing: gha, tier1-5

Thanks,
Thomas

---

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Issue

• JDK-8351921: G1: Pinned regions with pinned objects only reachable by native code crash VM (Bug - P2)

Reviewers

• Ivan Walulya (@walulyai - Reviewer) Review applies to 5dda6bbf
• Albert Mingkun Yang (@albertnetymk - Reviewer)

Reviewing

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[openjdk]

@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:

8351921: G1: Pinned regions with pinned objects only reachable by native code crash VM

Reviewed-by: ayang, iwalulya

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At the time when this comment was updated there had been 24 new commits pushed to the master branch:

• 19154f7: 8351970: Retire JavaLangAccess::exit
• 3aa6d62: 8351372: Improve negative tests coverage of jpackage
• 3239919: 8350835: C2 SuperWord: assert/wrong result when using Float.float16ToFloat with byte instead of short input
• 47c1960: 8351689: -Xshare:dump with default classlist fails on static JDK
• 6b82b42: 8348598: Update Libpng to 1.6.47
• 2674a31: 8351891: Disable TestBreakSignalThreadDump.java#with_jsig and XCheckJSig.java on static JDK
• 4c6a523: 8352096: Test jdk/jfr/event/profiling/TestFullStackTrace.java shouldn't be executed with -XX:+DeoptimizeALot
• d68775d: 8351995: JFR: Leftovers from removal of Security Manager
• e62becc: 8350964: Add an ArtifactResolver.fetch(clazz) method
• dbf47d6: 8351876: RISC-V: enable and fix some float round tests
• ... and 14 more: https://git.openjdk.org/jdk/compare/86b24339dc05422f61e10023f97a9013e2c03a15...master

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[mlbridge]

Webrevs

• 01: Full - Incremental (bfd96710)
• 00: Full (d0848bad)

[walulyai]

Looks good!

Nits:

[tschatzl]

Thanks @albertnetymk @walulyai for your reviews

/integrate

[openjdk]

Going to push as commit 558c015.
Since your change was applied there have been 28 commits pushed to the master branch:

• f8c2122: 8352138: G1: Remove G1AddMetaspaceDependency.java test
• e1bcff3: 8345687: Improve the implementation of SegmentFactories::allocateSegment
• f4ddac5: 8331201: UBSAN enabled build reports on Linux x86_64 runtime error: shift exponent 65 is too large for 64-bit type 'long unsigned int'
• 38499b3: 8352084: Add more test code in TestSetupAOT.java
• 19154f7: 8351970: Retire JavaLangAccess::exit
• 3aa6d62: 8351372: Improve negative tests coverage of jpackage
• 3239919: 8350835: C2 SuperWord: assert/wrong result when using Float.float16ToFloat with byte instead of short input
• 47c1960: 8351689: -Xshare:dump with default classlist fails on static JDK
• 6b82b42: 8348598: Update Libpng to 1.6.47
• 2674a31: 8351891: Disable TestBreakSignalThreadDump.java#with_jsig and XCheckJSig.java on static JDK
• ... and 18 more: https://git.openjdk.org/jdk/compare/86b24339dc05422f61e10023f97a9013e2c03a15...master

Your commit was automatically rebased without conflicts.

[openjdk]

@tschatzl Pushed as commit 558c015.

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