8351933: Inaccurate masking of TC subfield decrement in ForkJoinPool

[dchuyko]

This a backport of JDK-8351933 [0] (PR [1]) for 17u. At one of code paths the TC subfield of ctl field is decremented and the result is not masked correctly. As a result, the FJP may stop executing tasks [2]. The target code is in awaitWork() instead of tryTrim() and the surrounding code is different from the current master, as well as the original mask name. The core change is the same, candidate for compareAndSetCtl() is constructed using '(c & RC_MASK) | ((c - TC_UNIT) & TC_MASK)' instead of '(UC_MASK & (c - TC_UNIT))' to correctly preserve the RC subfield.

[0] https://bugs.openjdk.org/browse/JDK-8351933
[1] openjdk/jdk#24034
[2] https://bugs.openjdk.org/browse/JDK-8330017

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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-8351933 needs maintainer approval

Issue

• JDK-8351933: Inaccurate masking of TC subfield decrement in ForkJoinPool (Bug - P4 - Approved)

Reviewers

• Paul Hohensee (@phohensee - Reviewer)
• Doug Lea (@DougLea - Reviewer)

Reviewing

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[bridgekeeper]

👋 Welcome back dchuyko! 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]

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

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

8351933: Inaccurate masking of TC subfield decrement in ForkJoinPool

Reviewed-by: phh, dl

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At the time when this comment was updated there had been 19 new commits pushed to the master branch:

• 2dc6bac: 8328087: Automate javax/swing/JTable/TAB/TAB.java applet test
• b5f7d64: 8203867: Delete test java/awt/TrayIcon/DblClickActionEventTest/DblClickActionEventTest.html
• 759dc5f: 8328089: Automate javax/swing/JTable/4222153/bug4222153.java applet test
• ... and 16 more: https://git.openjdk.org/jdk17u-dev/compare/6b156585e70a639930f6965c0b3871de8b1a874b...master

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[openjdk]

This backport pull request has now been updated with the original issue, but not the original commit. If you have the original commit hash, please update the pull request title with Backport <hash>.

[mlbridge]

Webrevs

• 02: Full - Incremental (09d4316d)
• 01: Full - Incremental (7fbe301f)
• 00: Full (3bd11db2)

[openjdk]

⚠️ @dchuyko 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.

[dchuyko]

/approval request This a tiny bugfix in ForkJoinPool. At one of code paths the TC subfield of ctl field is decremented and the result is not masked correctly, so the RC subfield is not preserved. That sometimes leads to a stopped pool in 17 and 11 [0].

Testing: full jtreg tier1-3 and JCK for multiple supported platforms in the internal Liberica CI.

[0] https://bugs.openjdk.org/browse/JDK-8330017

[openjdk]

@dchuyko
8351933: The approval request has been created successfully.

[DougLea]

Yes, this corrects in the same way as in other releases

[bridgekeeper]

@dchuyko This pull request has been inactive for more than 4 weeks and will be automatically closed if another 4 weeks passes without any activity. To avoid this, simply issue a /touch or /keepalive command to the pull request. Feel free to ask for assistance if you need help with progressing this pull request towards integration!

[dchuyko]

/keepalive

[openjdk]

@dchuyko The pull request is being re-evaluated and the inactivity timeout has been reset.

[bridgekeeper]

@dchuyko This pull request has been inactive for more than 4 weeks and will be automatically closed if another 4 weeks passes without any activity. To avoid this, simply issue a /touch or /keepalive command to the pull request. Feel free to ask for assistance if you need help with progressing this pull request towards integration!

[GoeLin]

Hi @dchuyko
Do you still want to bring this to 17? If so, please merge head for new testing.

[GoeLin]

Removing label in the meantime.

[dchuyko]

Yes. Merged recent master.

[dchuyko]

/integrate

[openjdk]

@dchuyko
Your change (at version 09d4316) is now ready to be sponsored by a Committer.

[phohensee]

/sponsor

[openjdk]

Going to push as commit a897ee8.
Since your change was applied there have been 19 commits pushed to the master branch:

• 2dc6bac: 8328087: Automate javax/swing/JTable/TAB/TAB.java applet test
• b5f7d64: 8203867: Delete test java/awt/TrayIcon/DblClickActionEventTest/DblClickActionEventTest.html
• 759dc5f: 8328089: Automate javax/swing/JTable/4222153/bug4222153.java applet test
• ... and 16 more: https://git.openjdk.org/jdk17u-dev/compare/6b156585e70a639930f6965c0b3871de8b1a874b...master

Your commit was automatically rebased without conflicts.

[openjdk]

@phohensee @dchuyko Pushed as commit a897ee8.

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