[jboss-jira] [JBoss JIRA] Resolved: (JGRP-1103) NakReceiverWindow: concurrent insertion may insert the same seqno multiple times

NakReceiverWindow: concurrent insertion may insert the same seqno multiple times -------------------------------------------------------------------------------- Key: JGRP-1103 URL: https://jira.jboss.org/jira/browse/JGRP-1103 Project: JGroups Issue Type: Bug Reporter: Bela Ban Assignee: Bela Ban Priority: Blocker Fix For: 2.8 When concurrently inserting the same range of seqnos (e.g. 1-100) into the NakReceiverWindow by N threads (e.g. 10), we sometimes end up with duplicate messages for the *same* seqno ! This happens very rarely and only when many threads insert the same message ! This can be observed in DuplicateTest (testOOBMulticastsToAll3Senders()): sometimes the final list contains more than 10 elements. I reproduced this by testing NakReceiverWindow in isolation, the test is NakReceiverWindowTest2. I assume this is a regression introduced in 2.8 by moving insertions to and removal from xmit_table out of the write_lock scope in method NakReceiverWindow.add().