8088343: Race condition in javafx.concurrent.Task::cancel #1769

andy-goryachev-oracle · 2025-04-10T21:22:21Z

The code should not set the Task.state value to CANCELLED if the said task is already SUCCEEDED or FAILED.

This is a product bug.

Added @RepeatedTest(50) to the tests that used to fail intermittently - this made the test failed more reliably without the fix.

Progress

Change must not contain extraneous whitespace
Commit message must refer to an issue
Change must be properly reviewed (2 reviews required, with at least 1 Reviewer, 1 Author)

Issue

JDK-8088343: Race condition in javafx.concurrent.Task::cancel (Bug - P4)

Reviewers

Kevin Rushforth (@kevinrushforth - Reviewer)
Ambarish Rapte (@arapte - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jfx.git pull/1769/head:pull/1769
$ git checkout pull/1769

Update a local copy of the PR:
$ git checkout pull/1769
$ git pull https://git.openjdk.org/jfx.git pull/1769/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 1769

View PR using the GUI difftool:
$ git pr show -t 1769

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jfx/pull/1769.diff

Using Webrev

Link to Webrev Comment

bridgekeeper · 2025-04-10T21:22:34Z

👋 Welcome back angorya! 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 · 2025-04-10T21:22:55Z

@andy-goryachev-oracle 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:

8088343: Race condition in javafx.concurrent.Task::cancel

Reviewed-by: kcr, arapte

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 9 new commits pushed to the master branch:

c0b798b: 8355413: Re-enable InitializeJavaFXLaunchTests on Xorg
1b2f022: 8347359: RichTextArea API Tests
1a12966: 8354478: Improve StageStyle documentation
... and 6 more: https://git.openjdk.org/jfx/compare/bcf2ad530d55b626a638bac907c3f7de5fdb2d93...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.

mlbridge · 2025-04-10T21:35:52Z

Webrevs

kevinrushforth · 2025-04-10T22:15:27Z

Reviewers: @kevinrushforth @arapte

/reviewers 2

openjdk · 2025-04-10T22:16:03Z

@kevinrushforth
The total number of required reviews for this PR (including the jcheck configuration and the last /reviewers command) is now set to 2 (with at least 1 Reviewer, 1 Author).

kevinrushforth

Avoiding the case where we transition from FAILED or SUCCEEDED to CANCELLED is good, and should fix the test failures (although I'll do some additional testing), but I can't help wondering if underlying problem is something else. The question I have is: how do we get into a state where Worker.State of the Task one of the completion states (FAILED or SUCCEEDED), whereas the parent FutureTask is not completed, and so enters a canceled state. You can see this by instrumenting the code and calling super.isCancelled().

I wonder if the custom service created by TestServiceFactory is causing, or contributing to, the problem?

kevinrushforth · 2025-04-16T16:23:14Z

modules/javafx.graphics/src/main/java/javafx/concurrent/Task.java

+                switch (getState()) {
+                case FAILED:
+                case SUCCEEDED:


Avoiding transitioning from a one of the completion states to canceled is a good thing. My question, though is: how did we get here? Is this masking some other problem?

I think the variations in the test timing uncovered this issue. I don't think it's a problem with the execution of the task, but rather with the reporting of its final state.

kevinrushforth · 2025-04-16T16:35:39Z

modules/javafx.graphics/src/main/java/javafx/concurrent/Task.java

+                        break;
+                    }
+                });
+                return rv.get();


This is ineffective since you don't wait for the runLater to execute (and waiting could lead to deadlock, so I wouldn't recommend that). I don't think there is anything better than unconditionally returning flag when not running on the FX app thread. That's what the current code does (and is what your proposed fix will do most of the time).

good point!

In this particular case, returning true from cancel() when state will not be changed is acceptable.

kevinrushforth

LGTM. I instrumented the code and after a few test runs was able to spot a couple cases where this would have failed without the fix.

andy-goryachev-oracle · 2025-04-23T17:15:33Z

@arapte or @Ziad-Mid : could one of you be the second reviewer?

arapte

LGTM... Could observe test failure without this change.

andy-goryachev-oracle · 2025-04-24T14:37:24Z

Thank you Kevin and Ambarish!
/integrate

openjdk · 2025-04-24T14:38:45Z

Going to push as commit 48240da.
Since your change was applied there have been 11 commits pushed to the master branch:

22064a8: 8353632: [Linux] Undefined reference to PlatformSupport::OBSERVED_SETTINGS with C++14
2617ff5: 8318985: [macos] Incorrect 3D lighting on macOS 14 and later
c0b798b: 8355413: Re-enable InitializeJavaFXLaunchTests on Xorg
... and 8 more: https://git.openjdk.org/jfx/compare/bcf2ad530d55b626a638bac907c3f7de5fdb2d93...master

Your commit was automatically rebased without conflicts.

openjdk · 2025-04-24T14:38:56Z

@andy-goryachev-oracle Pushed as commit 48240da.

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

8088343

bb7c95c

andy-goryachev-oracle marked this pull request as ready for review April 10, 2025 21:31

openjdk bot added the rfr Ready for review label Apr 10, 2025

kevinrushforth self-requested a review April 11, 2025 16:08

Merge remote-tracking branch 'origin/master' into 8088343.lifecycle

d605fb9

kevinrushforth reviewed Apr 16, 2025

View reviewed changes

andy-goryachev-oracle added 3 commits April 16, 2025 13:03

Merge remote-tracking branch 'origin/master' into 8088343.lifecycle

136b8aa

review comments

33143f1

cleanup

66d2edb

andy-goryachev-oracle requested a review from kevinrushforth April 16, 2025 20:25

andy-goryachev-oracle changed the title ~~8088343: Intermittent unit test failure in javafx.concurrent.ServiceLifecycleTest~~ 8088343: Race condition in javafx.concurrent.Task::cancel Apr 21, 2025

kevinrushforth approved these changes Apr 23, 2025

View reviewed changes

arapte approved these changes Apr 24, 2025

View reviewed changes

openjdk bot added the ready Ready to be integrated label Apr 24, 2025

openjdk bot added the integrated Pull request has been integrated label Apr 24, 2025

openjdk bot closed this Apr 24, 2025

openjdk bot removed ready Ready to be integrated rfr Ready for review labels Apr 24, 2025

andy-goryachev-oracle deleted the 8088343.lifecycle branch April 24, 2025 14:39

8088343: Race condition in javafx.concurrent.Task::cancel #1769

8088343: Race condition in javafx.concurrent.Task::cancel #1769

Uh oh!

Conversation

andy-goryachev-oracle commented Apr 10, 2025 • edited by openjdk bot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Progress

Issue

Reviewers

Reviewing

Uh oh!

bridgekeeper bot commented Apr 10, 2025

Uh oh!

openjdk bot commented Apr 10, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

mlbridge bot commented Apr 10, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Webrevs

Uh oh!

kevinrushforth commented Apr 10, 2025

Uh oh!

openjdk bot commented Apr 10, 2025

Uh oh!

kevinrushforth left a comment

Choose a reason for hiding this comment

Uh oh!

kevinrushforth Apr 16, 2025

Choose a reason for hiding this comment

Uh oh!

andy-goryachev-oracle Apr 16, 2025

Choose a reason for hiding this comment

Uh oh!

kevinrushforth Apr 16, 2025

Choose a reason for hiding this comment

Uh oh!

andy-goryachev-oracle Apr 16, 2025

Choose a reason for hiding this comment

Uh oh!

kevinrushforth left a comment

Choose a reason for hiding this comment

Uh oh!

andy-goryachev-oracle commented Apr 23, 2025

Uh oh!

arapte left a comment

Choose a reason for hiding this comment

Uh oh!

andy-goryachev-oracle commented Apr 24, 2025

Uh oh!

openjdk bot commented Apr 24, 2025

Uh oh!

openjdk bot commented Apr 24, 2025

Uh oh!

Reviewers

Assignees

Labels

Milestone

Development

Uh oh!

3 participants

andy-goryachev-oracle commented Apr 10, 2025 •

edited by openjdk bot

Loading

openjdk bot commented Apr 10, 2025 •

edited

Loading

mlbridge bot commented Apr 10, 2025 •

edited

Loading