XAManagedConnectionFactory.isEqual(Object) deadlock in JBoss EAP

Environment

• Red Hat JBoss Enterprise Application Platform (EAP)
  • 7
  • 6

Issue

• Deadlock found in thread dump for threads executing org.jboss.jca.adapters.jdbc.xa.XAManagedConnectionFactory.isEqual(Object)

• Two or more threads hold one lock on an instance of java.util.Collections$SynchronizedMap and attempt to obtain a lock on a different instance (e.g. locks on 0xaaaaaaa and 0xbbbbbbb in the example below).

      "thread-one" ...
      java.lang.Thread.State: BLOCKED (on object monitor)
          at java.util.Collections$SynchronizedMap.get(Collections.java:2584)
          - waiting to lock <0xaaaaaaa> (a java.util.Collections$SynchronizedMap)
          at java.util.AbstractMap.equals(AbstractMap.java:495)
          at java.util.Collections$SynchronizedMap.equals(Collections.java:2631)
          - locked <0xbbbbbbb> (a java.util.Collections$SynchronizedMap)
          at org.jboss.jca.adapters.jdbc.xa.XAManagedConnectionFactory.isEqual(XAManagedConnectionFactory.java:563)
          - locked <0xbbbbbbb> (a java.util.Collections$SynchronizedMap)
          at org.jboss.jca.adapters.jdbc.xa.XAManagedConnectionFactory.equals(XAManagedConnectionFactory.java:598)
          at org.jboss.jca.adapters.jdbc.BaseWrapperManagedConnectionFactory$SubjectActions.doCheck(BaseWrapperManagedConnectionFactory.java:1397)
          at org.jboss.jca.adapters.jdbc.BaseWrapperManagedConnectionFactory$SubjectActions.addMatchingProperties(BaseWrapperManagedConnectionFactory.java:1508)
          at org.jboss.jca.adapters.jdbc.BaseWrapperManagedConnectionFactory.getConnectionProperties(BaseWrapperManagedConnectionFactory.java:1135)
          at org.jboss.jca.adapters.jdbc.xa.XAManagedConnectionFactory.matchManagedConnections(XAManagedConnectionFactory.java:533)
          ...
          at org.jboss.jca.adapters.jdbc.WrapperDataSource.getConnection(WrapperDataSource.java:138)
          at org.jboss.as.connector.subsystems.datasources.WildFlyDataSource.getConnection(WildFlyDataSource.java:66)
          ...
  
      "thread-two" ...
      java.lang.Thread.State: BLOCKED (on object monitor)
          at java.util.Collections$SynchronizedMap.size(Collections.java:2572)
          - waiting to lock <0xbbbbbbb> (a java.util.Collections$SynchronizedMap)
          at java.util.AbstractMap.equals(AbstractMap.java:482)
          at java.util.Collections$SynchronizedMap.equals(Collections.java:2631)
          - locked <0xaaaaaaa> (a java.util.Collections$SynchronizedMap)
          at org.jboss.jca.adapters.jdbc.xa.XAManagedConnectionFactory.isEqual(XAManagedConnectionFactory.java:563)
          - locked <0xaaaaaaa> (a java.util.Collections$SynchronizedMap)
          at org.jboss.jca.adapters.jdbc.xa.XAManagedConnectionFactory.equals(XAManagedConnectionFactory.java:598)
          ... [same stack as thread-one above] ...
          at org.jboss.jca.adapters.jdbc.WrapperDataSource.getConnection(WrapperDataSource.java:138)
          at org.jboss.as.connector.subsystems.datasources.WildFlyDataSource.getConnection(WildFlyDataSource.java:66)
          ...
  

Resolution

This issue¹ is resolved in This content is not included.EAP 7.1 cumulative patch (CP) 3 and later releases. Production systems should use the latest available cumulative patch.

This issue² is resolved in This content is not included.EAP 6.4 cumulative patch (CP) 21 and later releases. Production systems should use the latest available cumulative patch.

Root Cause

This is a known defect:

• Content from issues.jboss.org is not included.JBJCA-1371
• Content from issues.jboss.org is not included.WFLY-10181

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