aparnasuresh85 opened a new pull request, #3304: URL: https://github.com/apache/solr/pull/3304
https://issues.apache.org/jira/browse/SOLR-17720 <!-- _(If you are a project committer then you may remove some/all of the following template.)_ Before creating a pull request, please file an issue in the ASF Jira system for Solr: * https://issues.apache.org/jira/projects/SOLR For something minor (i.e. that wouldn't be worth putting in release notes), you can skip JIRA. To create a Jira issue, you will need to create an account there first. The title of the PR should reference the Jira issue number in the form: * SOLR-####: <short description of problem or changes> SOLR must be fully capitalized. A short description helps people scanning pull requests for items they can work on. Properly referencing the issue in the title ensures that Jira is correctly updated with code review comments and commits. --> # Description Please provide a short description of the changes you're making with this pull request. Fix deadlock possibility in CollectionPropertiesZkStateReader Please provide a short description of the approach taken to implement your solution. The deadlock occurs due to conflicting lock acquisition orders between removeCollectionPropsWatcher() and refreshAndWatch(): removeCollectionPropsWatcher() first locks collectionPropsObservers via compute(collection, <function>), then waits on getCollectionLock(collection). refreshAndWatch() first locks getCollectionLock(coll), then waits on collectionPropsObservers.remove(coll). To resolve this, the fix moves the synchronized (getCollectionLock(collection)) block outside the compute() call in removeCollectionPropsWatcher(), ensuring a consistent lock order and preventing deadlock. While the overall locking logic could be simplified further, this change specifically addresses the deadlock scenario. # Tests No new tests introduced. Ensure existing tests pass. # Checklist Please review the following and check all that apply: - [X] I have reviewed the guidelines for [How to Contribute](https://github.com/apache/solr/blob/main/CONTRIBUTING.md) and my code conforms to the standards described there to the best of my ability. - [ ] I have created a Jira issue and added the issue ID to my pull request title. - [ ] I have given Solr maintainers [access](https://help.github.com/en/articles/allowing-changes-to-a-pull-request-branch-created-from-a-fork) to contribute to my PR branch. (optional but recommended, not available for branches on forks living under an organisation) - [ ] I have developed this patch against the `main` branch. - [ ] I have run `./gradlew check`. - [ ] I have added tests for my changes. - [ ] I have added documentation for the [Reference Guide](https://github.com/apache/solr/tree/main/solr/solr-ref-guide) -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@solr.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@solr.apache.org For additional commands, e-mail: issues-h...@solr.apache.org
