[jboss-jira] [JBoss JIRA] Created: (JBAS-8626) QueuedPessimisticEJBLock released to early

[Judith Bürgstein (JIRA)]

QueuedPessimisticEJBLock released to early
------------------------------------------

                 Key: JBAS-8626
                 URL: https://jira.jboss.org/browse/JBAS-8626
             Project: JBoss Application Server
          Issue Type: Bug
      Security Level: Public (Everyone can see)
    Affects Versions: JBossAS-5.1.0.GA, JBossAS-3.2.7 Final
            Reporter: Judith Bürgstein


Usecase:
All xx, xy, yy and xz are representing readonly entitybean-methods and are called on one EntityBean. CMT required and reentrant true.
The following methods are executed on the server in this order: 

Thread1: calls entitybean.xx
Thread1: calls entitybean.xy
Thread2: calls entitybean.yy -> has to wait for the QueuedPessimisticEJBLock
Thread1: returns from entitybean.xy and frees the QueuedPessimisticEJBLock                    <--- BUG
Thread2: gets the QueuedPessimisticEJBLock but doesn't get the NonReentrantLock
Thread1: calls entitybean.xz -> has to wait for the QueuedPessimisticEJBLock and still holds the NonReentrantLock
Result: Undetected deadlock between QueuedPessimisticEJBLock and NonReentrantLock.

Our current workaround:
Created a subclass of QueuedPessimisticEJBLock and override problematic method "endInvocation":

public void endInvocation(Invocation P_mi)
    {
        Transaction F_tx = P_mi.getTransaction();
        if (F_tx != null && F_tx.equals(getTransaction()))
        {
            EntityEnterpriseContext F_ctx = (EntityEnterpriseContext)P_mi.getEnterpriseContext();

            if(F_ctx == null)
            {
                endTransaction(F_tx);
            }
            else if(F_ctx.hasTxSynchronization() == false)
            {
                NonReentrantLock F_mLock = F_ctx.getMethodLock();
                
                if (F_mLock == null)
                {
                    endTransaction(F_tx);
                }
                else
                {
                    Object F_resourceHolder = F_mLock.getResourceHolder();
                    if (F_resourceHolder instanceof Thread
                            && Thread.currentThread().equals(F_resourceHolder))
                    {
                        // don't end the transaction, because we still own the
                        // lock!
                    }
                    else if (F_resourceHolder instanceof Transaction
                            && F_tx.equals(F_resourceHolder))
                    {
                        // don't end the transaction, because we still own the
                        // lock!
                    }
                    else
                    {
                        endTransaction(F_tx);
                    }
                }
            }
            else
            {
                //hasTxSynchronization is true -> don't end the transaction
            }
        }
    }

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