[jdk11u-dev] Integrated: 8351933: Inaccurate masking of TC subfield decrement in ForkJoinPool

[Dmitry Chuyko]

On Thu, 13 Mar 2025 14:57:19 GMT, Dmitry Chuyko <dchuyko at openjdk.org> wrote:

> This a backport of JDK-8351933 [0] (PR [1]) for 11u. At one of code paths the TC subfield of ctl field is decremented and the result is not masked correctly. The target code is in runWorker() instead of tryTrim()/awaitWork() 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 CTL.compareAndSet is constructed using '(RC_MASK & c) | (TC_MASK & (c - TC_UNIT))' instead of '(UC_MASK & (c - TC_UNIT))' to correctly preserve the RC subfield.
> 
> [0] https://bugs.openjdk.org/browse/JDK-8351933
> [1] https://github.com/openjdk/jdk/pull/24034

This pull request has now been integrated.

Changeset: 8a139678
Author:    Dmitry Chuyko <dchuyko at openjdk.org>
Committer: Paul Hohensee <phh at openjdk.org>
URL:       https://git.openjdk.org/jdk11u-dev/commit/8a139678771b9136bd7c05bcf4f72e48be6300c6
Stats:     1 line in 1 file changed: 0 ins; 0 del; 1 mod

8351933: Inaccurate masking of TC subfield decrement in ForkJoinPool

Reviewed-by: phh, dl

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PR: https://git.openjdk.org/jdk11u-dev/pull/3012