8276201: Shenandoah: Race results degenerated GC to enter wrong entry point

[zhengyu123]

There is subtle race when concurrent GC comes out of final mark safepoint: an allocation failure occurred before control thread checks OOM conditional, that triggers degenerated GC enters "mark" degenerated point.

Degenerated GC re-executes final mark, then switching off SATB, but it is already off, because concurrent GC already completed final mark, that triggers the assertion.

The solution is to consult concurrent_mark_in_progress flag when selects degen-point.

Test:

• hotspot_gc_shenandoah

---

Progress

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Issue

• JDK-8276201: Shenandoah: Race results degenerated GC to enter wrong entry point

Reviewers

• Aleksey Shipilev (@shipilev - Reviewer)

Reviewing

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[bridgekeeper]

👋 Welcome back zgu! 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]

@zhengyu123 The following labels will be automatically applied to this pull request:

• hotspot-gc
• shenandoah

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[mlbridge]

Webrevs

• 00: Full (c46c2595)

[shipilev]

Looks fine.

[openjdk]

@zhengyu123 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:

8276201: Shenandoah: Race results degenerated GC to enter wrong entry point

Reviewed-by: shade

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 106 new commits pushed to the master branch:

• 5bb1992: 8275868: ciReplay: Inlining fails with "unloaded signature classes" due to wrong protection domains
• 158831e: 8274320: os::fork_and_exec() should be using posix_spawn
• bf2e9ee: 8275080: G1CollectedHeap::expand() returns the wrong value
• b7104ba: 8196017: java/awt/Mouse/GetMousePositionTest/GetMousePositionWithPopup.java fails
• 6875678: 8273831: PrintServiceLookup spawns 2 threads in the current classloader, getting orphaned
• 5bbc8d3: 8274621: NullPointerException because listenAddress[0] is null
• 5021a12: 8274855: vectorapi tests failing with assert(!vbox->is_Phi()) failed
• fe6a202: 8271356: Modify jdb to treat an empty command as a repeat of the previous command
• cef9db9: 8276039: Remove unnecessary qualifications of java_lang_Class::
• 13265f9: 8274750: java/io/File/GetXSpace.java failed: '/dev': 191488 != 190976
• ... and 96 more: https://git.openjdk.java.net/jdk/compare/af14650127de47058b958be411503584c0ba6323...master

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.

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

[zhengyu123]

Thanks, @shipilev

[zhengyu123]

/integrate

[openjdk]

Going to push as commit dbf5100.
Since your change was applied there have been 106 commits pushed to the master branch:

• 5bb1992: 8275868: ciReplay: Inlining fails with "unloaded signature classes" due to wrong protection domains
• 158831e: 8274320: os::fork_and_exec() should be using posix_spawn
• bf2e9ee: 8275080: G1CollectedHeap::expand() returns the wrong value
• b7104ba: 8196017: java/awt/Mouse/GetMousePositionTest/GetMousePositionWithPopup.java fails
• 6875678: 8273831: PrintServiceLookup spawns 2 threads in the current classloader, getting orphaned
• 5bbc8d3: 8274621: NullPointerException because listenAddress[0] is null
• 5021a12: 8274855: vectorapi tests failing with assert(!vbox->is_Phi()) failed
• fe6a202: 8271356: Modify jdb to treat an empty command as a repeat of the previous command
• cef9db9: 8276039: Remove unnecessary qualifications of java_lang_Class::
• 13265f9: 8274750: java/io/File/GetXSpace.java failed: '/dev': 191488 != 190976
• ... and 96 more: https://git.openjdk.java.net/jdk/compare/af14650127de47058b958be411503584c0ba6323...master

Your commit was automatically rebased without conflicts.

[openjdk]

@zhengyu123 Pushed as commit dbf5100.

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