PK20083: DEADLOCKS OCCURRING IN THE SESSION MANAGER

 A fix is available

Obtain the fix for this APAR



APAR status
Closed as program error.

Error description
The customer has a total of two nodes, and each node has two
AppServers fora total of four AppServers. All four AppServers
belong to the same cluster. When the customer shut down two
AppServers in Node A, one AppServer in Node B was hung (the
other AppServer in Node B did not hang and performed as
expected).
.
When analyzing the customer's dumps, the following deadlock
was detected:
"Deadlock(s) detected !!!
     Thread 0x0x9b8690 "DRSThreadPool : 2"
       is waiting to be notified for: (0x2a6fbd68)
"com/ibm/ws/webcontainer/httpsession/DRSSessionData"
        which is owned by:
        Thread 0x0x9bf828 "WebSphere t=009bf828"
        which is waiting to be notified for:
           (0x1d8be2b8) "java/util/HashMap"
            which is owned by:
         Thread 0x0x9b8690 "DRSThreadPool : 2"
.
The following code stack was shown for the thread:
9b8690
       CEEOPCW
       pthread_cond_wait
       condWait
       sysMonitorWait
       lkMonitorEnter
com/ibm/ws/webcontainer/httpsession/DRSSessionData.clone()java/
lang/Object;
com/ibm/ws/webcontainer/httpsession/DRSHttpSessCache.convertSess
ion(com/ibm/ws/webcontainer/httpsession/DRSSessionData;)com/ibm/
ws/webcontainer/httpsession/DRSSessionData;
.
This is a route of APAR 
PQ84217.
.
The 5.1 5655I3500 version of this fix was fixed via internal
defect MD20543 which was included in z/OS rollup apar 
PQ99636
which ships in service level W510204.
Local fix Problem summary
****************************************************************
* USERS AFFECTED: All users of WebSphere Application Server    *
*                 V5.0 for z/OS                                *
****************************************************************
* PROBLEM DESCRIPTION: When the Application Server             *
*                      administrator restarts Application      *
*                      Servers one by one in a Network         *
*                      Deployment cluster, a deadlock occurs.  *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
When an administrator restarts Application Server one by one in
ND cluster, the thread that is about to shutdown the session
manager conflicts with another thread that is sending local
session data to another newly started app server in the ND
cluster.  This causes a deadlock to occur.
Problem conclusion
The code was modified to prevent the deadlock.

APAR PK20083 is associated with SERVICE LEVEL W502039 of
WebSphere Application Server V5.0 for z/OS.
Temporary fix Comments
APAR information
APAR number PK20083
Reported component name WEBSPHERE FOR Z
Reported component ID 5655I3500
Reported release 500
Status CLOSED PER
PE NoPE
HIPER NoHIPER
Special Attention NoSpecatt
Submitted date 2006-02-19
Closed date 2006-03-20
Last modified date 2006-10-17

APAR is sysrouted FROM one or more of the following:
PQ84217

APAR is sysrouted TO one or more of the following:

Modules/Macros
BBOUBINF          

Publications Referenced

Fix information
Fixed component name WEBSPHERE FOR Z
Fixed component ID 5655I3500

Applicable component levels
R500 PSY UK12774    UP06/03/24 P F603

  Fix is available
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Document Information


Current web document: swg1PK20083.html
Product categories: Software > Application Servers > Distributed Application & Web Servers > WebSphere Application Server for z/OS
Operating system(s):
Software version: 500
Software edition:
Reference #: PK20083
IBM Group: Software Group
Modified date: Oct 17, 2006