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https://issues.apache.org/jira/browse/JCR-3226?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14634838#comment-14634838
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Thomas Mueller commented on JCR-3226:
-------------------------------------
Potential patch to fix the problem. This requires a code review.
{noformat}
--- src/main/java/org/apache/jackrabbit/core/state/SessionItemStateManager.java
(revision 1691398)
+++ src/main/java/org/apache/jackrabbit/core/state/SessionItemStateManager.java
(working copy)
@@ -803,7 +803,19 @@
visibleState = transientState;
}
}
- dispatcher.notifyStateCreated(visibleState);
+ boolean notifyTransientSpace;
+ if (visibleState instanceof NodeState) {
+ // No need to push "node created" to transient space:
+ // either the transient already knows about this state, or it
doesn't.
+ // If we notify in this case, this can lead to a deadlock,
+ // see JCR-3226.
+ notifyTransientSpace = false;
+ } else {
+ notifyTransientSpace = true;
+ }
+ if (notifyTransientSpace) {
+ dispatcher.notifyStateCreated(visibleState);
+ }
}
/**
{noformat}
> stateCreated deadlock
> ---------------------
>
> Key: JCR-3226
> URL: https://issues.apache.org/jira/browse/JCR-3226
> Project: Jackrabbit Content Repository
> Issue Type: Bug
> Components: jackrabbit-core
> Affects Versions: 2.2, 2.4
> Reporter: Jukka Zitting
> Assignee: Thomas Mueller
> Labels: deadlock
> Attachments: JCR-3226-test-2.patch, JCR-3226-test.patch
>
>
> In JCR-2650 a potential deadlock in SessionItemStateManager.stateModified()
> got fixed by postponing the work to the save() call.
> Unfortunately this still leaves the stateCreated() method vulnerable to a
> similar (though much less likely) deadlock scenario (observed in Jackrabbit
> 2.2.x):
> Thread A:
> at org.apache.jackrabbit.core.state.NodeState.copy(NodeState.java:118)
> - waiting to lock <0x00007ffec8ddfa18> (a
> org.apache.jackrabbit.core.state.NodeState)
> - locked <0x00007ffec8ddf9d8> (a
> org.apache.jackrabbit.core.state.NodeState)
> at org.apache.jackrabbit.core.state.ItemState.pull(ItemState.java:152)
> - locked <0x00007ffec8ddf9d8> (a
> org.apache.jackrabbit.core.state.NodeState)
> at
> org.apache.jackrabbit.core.state.SessionItemStateManager.stateCreated(SessionItemStateManager.java:791)
> at
> org.apache.jackrabbit.core.state.StateChangeDispatcher.notifyStateCreated(StateChangeDispatcher.java:94)
> at
> org.apache.jackrabbit.core.state.LocalItemStateManager.stateCreated(LocalItemStateManager.java:428)
> at
> org.apache.jackrabbit.core.state.StateChangeDispatcher.notifyStateCreated(StateChangeDispatcher.java:94)
> at
> org.apache.jackrabbit.core.state.SharedItemStateManager.stateCreated(SharedItemStateManager.java:398)
> at
> org.apache.jackrabbit.core.state.ItemState.notifyStateCreated(ItemState.java:231)
> at
> org.apache.jackrabbit.core.state.ChangeLog.persisted(ChangeLog.java:309)
> at
> org.apache.jackrabbit.core.state.SharedItemStateManager$Update.end(SharedItemStateManager.java:777)
> at
> org.apache.jackrabbit.core.state.SharedItemStateManager.update(SharedItemStateManager.java:1488)
> at
> org.apache.jackrabbit.core.state.LocalItemStateManager.update(LocalItemStateManager.java:351)
> at
> org.apache.jackrabbit.core.state.XAItemStateManager.update(XAItemStateManager.java:354)
> at
> org.apache.jackrabbit.core.state.LocalItemStateManager.update(LocalItemStateManager.java:326)
> at
> org.apache.jackrabbit.core.state.SessionItemStateManager.update(SessionItemStateManager.java:289)
> at
> org.apache.jackrabbit.core.ItemSaveOperation.perform(ItemSaveOperation.java:258)
> at
> org.apache.jackrabbit.core.session.SessionState.perform(SessionState.java:200)
> at org.apache.jackrabbit.core.ItemImpl.perform(ItemImpl.java:91)
> at org.apache.jackrabbit.core.ItemImpl.save(ItemImpl.java:329)
> Thread B:
> at org.apache.jackrabbit.core.state.NodeState.copy(NodeState.java:119)
> - waiting to lock <0x00007ffec8ddf9d8> (a
> org.apache.jackrabbit.core.state.NodeState)
> - locked <0x00007ffec8ddfa18> (a
> org.apache.jackrabbit.core.state.NodeState)
> at org.apache.jackrabbit.core.NodeImpl.makePersistent(NodeImpl.java:869)
> - locked <0x00007ffec8ddfa18> (a
> org.apache.jackrabbit.core.state.NodeState)
> at
> org.apache.jackrabbit.core.ItemSaveOperation.persistTransientItems(ItemSaveOperation.java:836)
> at
> org.apache.jackrabbit.core.ItemSaveOperation.perform(ItemSaveOperation.java:243)
> at
> org.apache.jackrabbit.core.session.SessionState.perform(SessionState.java:200)
> at org.apache.jackrabbit.core.ItemImpl.perform(ItemImpl.java:91)
> at org.apache.jackrabbit.core.ItemImpl.save(ItemImpl.java:329)
> at
> org.apache.jackrabbit.core.session.SessionSaveOperation.perform(SessionSaveOperation.java:42)
> at
> org.apache.jackrabbit.core.session.SessionState.perform(SessionState.java:200)
> at org.apache.jackrabbit.core.SessionImpl.perform(SessionImpl.java:355)
> at org.apache.jackrabbit.core.SessionImpl.save(SessionImpl.java:758)
> IIUC this can only occur when two sessions are concurrently importing a node
> with the same UUID.
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