[infinispan-issues] [JBoss JIRA] (ISPN-5524) Race condition in SemaphoreCompletionService.executeFront()

Race condition in SemaphoreCompletionService.executeFront() ----------------------------------------------------------- Key: ISPN-5524 URL: https://issues.jboss.org/browse/ISPN-5524 Project: Infinispan Issue Type: Bug Components: Core Affects Versions: 7.2.2.Final, 8.0.0.Alpha1 Reporter: Dan Berindei Assignee: Dan Berindei Priority: Blocker Labels: testsuite_stability Fix For: 8.0.0.Alpha2, 7.2.3.Final, 8.0.0.Final If two threads call {{executeFront()}} at the same time, it's possible that none of them executes any task, although there are permits available, and one of the threads just added a task in the queue. This scenario causes random initial state transfer timeouts in the testsuite: # T1: continueTaskInBackground(): queue = empty, permits = 0 # T1: backgroundTaskFinished() # T1: = semaphore.release(): queue = empty, permits = 1 # T1: = executeFront() # T1: == semaphore.acquire() -> true: queue = empty, permits = 0 # T2: == queue.poll() -> null # T2: submit(task) # T2: = executeFront() # T2: == semaphore.acquire() -> false # T2: return without executing any task # T1: return without executing any task Failure example: http://ci.infinispan.org/viewLog.html?buildId=27153&tab=buildResultsD...