APAR status
Closed as program error.
Error description
WAS v5.0.2 on SUN Solaris 8
Customer ran the Stress test for 6-8 hrs with a large volume of
users. Then their AppServer crashed. The thread dump shows a
deadlock between two threads, one was waiting for a connection
from the free pool, and the other was returning a connection to
the free pool. This deadlock did not show up in every thread
dump customer had taken after evry AppServer hang or crash
before. The part of the stack, taken
from the thread dump, of two deadlocked threads are given below:
FOUND A JAVA LEVEL DEADLOCK:
----------------------------
"Servlet.Engine.Transports : 17":
waiting to lock monitor 0x3556328 (object 0xc0bf4c48, a
java.lang.Object),
which is locked by "Servlet.Engine.Transports : 83"
"Servlet.Engine.Transports : 83":
waiting to lock monitor 0x1602f10 (object 0xc0bfde50, a
java.lang.Object),
which is locked by "Servlet.Engine.Transports : 17"
JAVA STACK INFORMATION FOR THREADS LISTED ABOVE:
------------------------------------------------
Java Stack for "Servlet.Engine.Transports : 17":
==========
at
com.ibm.ejs.j2c.poolmanager.FreePool.createOrWaitForConnection(F
reePool.java:1088)
at
com.ibm.ejs.j2c.poolmanager.PoolManager.reserve(PoolManager.java
:1505)
at
com.ibm.ejs.j2c.ConnectionManager.allocateMCWrapper(ConnectionMa
nager.java:658)
at
com.ibm.ejs.j2c.ConnectionManager.allocateConnection(ConnectionM
anager.java:446)
at
com.ibm.ws.rsadapter.jdbc.WSJdbcDataSource.getConnection(WSJdbcD
ataSource.java:215)
at
com.ibm.ws.rsadapter.jdbc.WSJdbcDataSource.getConnection(WSJdbcD
ataSource.java:190).................
Java Stack for "Servlet.Engine.Transports : 83":
==========
at
com.ibm.ejs.j2c.poolmanager.FreePool.returnToFreePool(FreePool.j
ava:358)
at
com.ibm.ejs.j2c.poolmanager.PoolManager.release(PoolManager.java
:1209)
at
com.ibm.ejs.j2c.MCWrapper.releaseToPoolManager(MCWrapper.java:16
55)
at
com.ibm.ejs.j2c.LocalTransactionWrapper.afterCompletionCode(Loca
lTransactionWrapper.java:1086)
Local fix Problem summary
****************************************************************
* USERS AFFECTED: WebSphere Application Server users of JCA, *
* JDBC, and JMS Connections. *
****************************************************************
* PROBLEM DESCRIPTION: This fixes a deadlock in the *
* ConnectionPool, during some exception *
* processing. *
****************************************************************
* RECOMMENDATION: *
****************************************************************
A deadlock can occur when an exception occurs while creating a
new connection, if another thread is releasing a connection to
the pool.
The java cores will look something like this :
FOUND A JAVA LEVEL DEADLOCK:
----------------------------
"Servlet.Engine.Transports : 17":
waiting to lock monitor 0x3556328 (object 0xc0bf4c48,
a java.lang.Object),
which is locked by "Servlet.Engine.Transports : 83"
"Servlet.Engine.Transports : 83":
waiting to lock monitor 0x1602f10 (object 0xc0bfde50,
a java.lang.Object),
which is locked by "Servlet.Engine.Transports : 17"
JAVA STACK INFORMATION FOR THREADS LISTED ABOVE:
------------------------------------------------
Java Stack for "Servlet.Engine.Transports : 17":
==========
at com.ibm.ejs.j2c.poolmanager.FreePool.
createOrWaitForConnection(FreePool.java:1088)
at com.ibm.ejs.j2c.poolmanager.PoolManager.
reserve(PoolManager.java:1505)
. . . .
Java Stack for "Servlet.Engine.Transports : 83":
==========
at com.ibm.ejs.j2c.poolmanager.FreePool.
returnToFreePool(FreePool.java:358)
at com.ibm.ejs.j2c.poolmanager.PoolManager.
release(PoolManager.java:1209)
. . . .
Problem conclusion
Moved synchronization point to outside of
createOrWaitForConneciton.
Temporary fix Comments
APAR information |
APAR number |
PQ88471 |
Reported component name |
WAS BASE 5.0 |
Reported component ID |
5630A3600 |
Reported release |
00S |
Status |
CLOSED PER |
PE |
NoPE |
HIPER |
NoHIPER |
Special Attention |
NoSpecatt |
Submitted date |
2004-05-05 |
Closed date |
2004-05-17 |
Last modified date |
2004-05-17 |
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
PK26206
Modules/Macros
Publications Referenced
Applicable component levels |
R003 PSY |
UP |
R00A PSY |
UP |
R00H PSY |
UP |
R00I PSY |
UP |
R00P PSY |
UP |
R00S PSY |
UP |
R00W PSY |
UP |
R103 PSY |
UP |
R10A PSY |
UP |
R10H PSY |
UP |
R10I PSY |
UP |
R10P PSY |
UP |
R10S PSY |
UP |
R10W PSY |
UP |
|