Mailing-List: contact dev-help@jackrabbit.apache.org; run by ezmlm
Precedence: bulk
Reply-To: dev@jackrabbit.apache.org
Message-ID: <19073735.1166020462326.JavaMail.jira@brutus>
Date: Wed, 13 Dec 2006 06:34:22 -0800 (PST)
From: "Przemo Pakulski (JIRA)" <jira@apache.org>
To: dev@jackrabbit.apache.org
Subject: [jira] Commented: (JCR-672) Deadlock on concurrent save/checkin
 operations possible
In-Reply-To: <9709571.1165921341093.JavaMail.jira@brutus>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit

    [ http://issues.apache.org/jira/browse/JCR-672?page=comments#action_12458141 ] 
            
Przemo Pakulski commented on JCR-672:
-------------------------------------

You're right deadlock has not been introduced by JCR-546, but it seems that currently is easier to reproduce it.

Inconsistent order of acquiring locks was already there. SharedItemStateManager  read lock should be acquired first, or if both components (SharedItemStateManager, AbstractVersionManager) ae really coupled together, maybe solution is to get rid of one and use single lock instead.


> Deadlock on concurrent save/checkin operations possible
> -------------------------------------------------------
>
>                 Key: JCR-672
>                 URL: http://issues.apache.org/jira/browse/JCR-672
>             Project: Jackrabbit
>          Issue Type: Bug
>          Components: versioning
>            Reporter: Przemo Pakulski
>
> Save and checkin operations are trying to acquire 2 locks in different order, what leads to deadlock.
> ->save
> 1.SharedItemStateManager.acquireWriteLock
> 2.AbstractVersionManager.acquireWriteLock	->	locked
> ->checkin
> 1.AbstractVersionManager.acquireWriteLock
> 2.SharedItemStateManager.acquireReadLock	->	locked
> "Thread-4" prio=6 tid=0x0312d840 nid=0x824 in Object.wait() [0x03cef000..0x03cefa68]
> 	at java.lang.Object.wait(Native Method)
> 	- waiting on <0x23210968> (a EDU.oswego.cs.dl.util.concurrent.WriterPreferenceReadWriteLock$WriterLock)
> 	at java.lang.Object.wait(Unknown Source)
> 	at EDU.oswego.cs.dl.util.concurrent.WriterPreferenceReadWriteLock$WriterLock.acquire(Unknown Source)
> 	- locked <0x23210968> (a EDU.oswego.cs.dl.util.concurrent.WriterPreferenceReadWriteLock$WriterLock)
> 	at org.apache.jackrabbit.core.version.AbstractVersionManager.acquireWriteLock(AbstractVersionManager.java:124)
> 	at org.apache.jackrabbit.core.version.VersionManagerImpl.setNodeReferences(VersionManagerImpl.java:413)
> 	at org.apache.jackrabbit.core.version.VersionItemStateProvider.setNodeReferences(VersionItemStateProvider.java:125)
> 	at org.apache.jackrabbit.core.state.SharedItemStateManager$Update.end(SharedItemStateManager.java:699)
> 	at org.apache.jackrabbit.core.state.SharedItemStateManager.update(SharedItemStateManager.java:810)
> 	at org.apache.jackrabbit.core.state.LocalItemStateManager.update(LocalItemStateManager.java:326)
> 	at org.apache.jackrabbit.core.state.XAItemStateManager.update(XAItemStateManager.java:313)
> 	at org.apache.jackrabbit.core.state.LocalItemStateManager.update(LocalItemStateManager.java:302)
> 	at org.apache.jackrabbit.core.state.SessionItemStateManager.update(SessionItemStateManager.java:295)
> 	at org.apache.jackrabbit.core.ItemImpl.save(ItemImpl.java:1204)
> 	- locked <0x2332eaa0> (a org.apache.jackrabbit.core.XASessionImpl)
> 	at JrTestDeadlock.run(JrTestDeadlock.java:87)
> "Thread-3" prio=6 tid=0x0312db18 nid=0xa04 in Object.wait() [0x03caf000..0x03cafae8]
> 	at java.lang.Object.wait(Native Method)
> 	- waiting on <0x232d1360> (a EDU.oswego.cs.dl.util.concurrent.WriterPreferenceReadWriteLock$ReaderLock)
> 	at java.lang.Object.wait(Unknown Source)
> 	at EDU.oswego.cs.dl.util.concurrent.WriterPreferenceReadWriteLock$ReaderLock.acquire(Unknown Source)
> 	- locked <0x232d1360> (a EDU.oswego.cs.dl.util.concurrent.WriterPreferenceReadWriteLock$ReaderLock)
> 	at org.apache.jackrabbit.core.state.SharedItemStateManager.acquireReadLock(SharedItemStateManager.java:1361)
> 	at org.apache.jackrabbit.core.state.SharedItemStateManager.hasItemState(SharedItemStateManager.java:270)
> 	at org.apache.jackrabbit.core.state.LocalItemStateManager.hasItemState(LocalItemStateManager.java:180)
> 	at org.apache.jackrabbit.core.state.XAItemStateManager.hasItemState(XAItemStateManager.java:252)
> 	at org.apache.jackrabbit.core.state.SessionItemStateManager.hasItemState(SessionItemStateManager.java:188)
> 	at org.apache.jackrabbit.core.ItemManager.itemExists(ItemManager.java:256)
> 	at org.apache.jackrabbit.core.NodeImpl.hasProperty(NodeImpl.java:1509)
> 	at org.apache.jackrabbit.core.version.InternalFrozenNodeImpl.checkin(InternalFrozenNodeImpl.java:276)
> 	at org.apache.jackrabbit.core.version.InternalFrozenNodeImpl.checkin(InternalFrozenNodeImpl.java:248)
> 	at org.apache.jackrabbit.core.version.InternalVersionHistoryImpl.checkin(InternalVersionHistoryImpl.java:440)
> 	at org.apache.jackrabbit.core.version.AbstractVersionManager.checkin(AbstractVersionManager.java:397)
> 	at org.apache.jackrabbit.core.version.VersionManagerImpl$2.run(VersionManagerImpl.java:289)
> 	at org.apache.jackrabbit.core.version.VersionManagerImpl$DynamicESCFactory.doSourced(VersionManagerImpl.java:611)
> 	- locked <0x2320c5d8> (a org.apache.jackrabbit.core.version.VersionManagerImpl$DynamicESCFactory)
> 	at org.apache.jackrabbit.core.version.VersionManagerImpl.checkin(VersionManagerImpl.java:285)
> 	at org.apache.jackrabbit.core.version.XAVersionManager.checkin(XAVersionManager.java:161)
> 	at org.apache.jackrabbit.core.NodeImpl.checkin(NodeImpl.java:2944)
> 	at JrTestDeadlock.run(JrTestDeadlock.java:103)

-- 
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa
-
For more information on JIRA, see: http://www.atlassian.com/software/jira