hshi2022 opened a new pull request, #12634: URL: https://github.com/apache/kafka/pull/12634
…ntRequestQuotaManager. In the version Scala 2.12, the lazy val initialization is under the object lock. The deadlock could happen in the following condition: In thread a, when ClientRequestQuotaManager.exemptSensor is being initialized, it has acquired the object lock and enters the the actual initialization block. The initialization of 'exemptSensor' requires another lock private val lock = new ReentrantReadWriteLock() and it is waiting for this lock. In thread b, at the same time, ClientQuotaManager.updateQuota() is called and it has already acquired ReentrantReadWriteLock lock by calling lock.writeLock().lock(). And then it executes info(). If this is the first time accessing Logging.logger, which is also a lazy val, it need to wait for the object lock. The deadlock happens. Since the lazy val initialization is under the object lock, we should avoid using lazy val if the initialization function holds another lock to prevent holding two locks at the same time which is prone for deadlock. Change to create exemptSensor during ClientRequestQuotaManager initialization with an expiration time of Long.MaxValue to prevent expiration if request quota is not enabled at that time. *More detailed description of your change, if necessary. The PR title and PR message become the squashed commit message, so use a separate comment to ping reviewers.* *Summary of testing strategy (including rationale) for the feature or bug fix. Unit and/or integration tests are expected for any behaviour change and system tests should be considered for larger changes.* ### Committer Checklist (excluded from commit message) - [ ] Verify design and implementation - [ ] Verify test coverage and CI build status - [ ] Verify documentation (including upgrade notes) -- 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: jira-unsubscr...@kafka.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
