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Posted to issues@activemq.apache.org by "ASF subversion and git services (JIRA)" <ji...@apache.org> on 2015/09/28 15:42:04 UTC
[jira] [Commented] (AMQ-5984) Unsafe use of access-order
LinkedHashMap via ActiveMQMessageAuditNoSync - can lead to loop and hang
[ https://issues.apache.org/jira/browse/AMQ-5984?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14933300#comment-14933300 ]
ASF subversion and git services commented on AMQ-5984:
------------------------------------------------------
Commit f6e1054a4b7eb67568982acc2a3dd488db21e509 in activemq's branch refs/heads/master from [~gtully]
[ https://git-wip-us.apache.org/repos/asf?p=activemq.git;h=f6e1054 ]
https://issues.apache.org/jira/browse/AMQ-5984 - fix sync on get for access ordered LinkedHashMap
> Unsafe use of access-order LinkedHashMap via ActiveMQMessageAuditNoSync - can lead to loop and hang
> ----------------------------------------------------------------------------------------------------
>
> Key: AMQ-5984
> URL: https://issues.apache.org/jira/browse/AMQ-5984
> Project: ActiveMQ
> Issue Type: Bug
> Components: Broker
> Affects Versions: 5.12.0
> Reporter: Gary Tully
> Assignee: Gary Tully
> Fix For: 5.13.0
>
>
> A thread looping in{code}"ActiveMQ Transport: tcp:///xxx:yyy@61616" daemon prio=10 tid=0x00007efff40a3000 nid=0x74f0 runnable [0x00007eff6f0f9000]
> java.lang.Thread.State: RUNNABLE
> at java.util.LinkedHashMap.transfer(LinkedHashMap.java:253)
> at java.util.HashMap.resize(HashMap.java:581)
> at java.util.HashMap.addEntry(HashMap.java:879)
> at java.util.LinkedHashMap.addEntry(LinkedHashMap.java:427)
> at java.util.HashMap.put(HashMap.java:505)
> at org.apache.activemq.ActiveMQMessageAuditNoSync.isDuplicate(ActiveMQMessageAuditNoSync.java:133)
> at org.apache.activemq.store.kahadb.MessageDatabase.upadateIndex(MessageDatabase.java:1238)
> at org.apache.activemq.store.kahadb.MessageDatabase$AddOpperation.execute(MessageDatabase.java:2196)
> at org.apache.activemq.store.kahadb.MessageDatabase$15.execute(MessageDatabase.java:1141)
> at org.apache.activemq.store.kahadb.disk.page.Transaction.execute(Transaction.java:779)
> at org.apache.activemq.store.kahadb.MessageDatabase.process(MessageDatabase.java:1137)
> at org.apache.activemq.store.kahadb.MessageDatabase$10.visit(MessageDatabase.java:1005)
> at org.apache.activemq.store.kahadb.data.KahaCommitCommand.visit(KahaCommitCommand.java:130)....{code}
> points to the need for a write lock on access to the LRUCache used for duplicate detection for failover producers.
> The index lock protects modifications on put etc but clearly a get needs to have exclusive access. Tis in the javadoc in bold - "In access-ordered linked hash maps, merely querying the map with get is a structural modification"
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