PK70786: POOR RANDOMIZATION FOR COM.IBM.WEBSPHERE.MANAGEMENT.JMX.RANDOM

Fixes are available

APAR status

Closed as program error.

Error description

JMX unicall invocations distributed among active servants
under control of the system property
com.ibm.websphere.management.jmx.random
are insufficiently random when multiple threads are
"simultaneously" accessing the servant MBean invoker.

Local fix

Problem summary

****************************************************************
* USERS AFFECTED: All IBM WebSphere Application Server         *
*                 V6.0.1 users on z/OS who                     *
*                 also use the system property                 *
*                 com.ibm.websphere.management.jmx.random      *
****************************************************************
* PROBLEM DESCRIPTION: If random invocation among multiple     *
*                      z/OS servant regions is in effect       *
*                      because the system property             *
*                      com.ibm.websphere.management.jmx.random *
*                      has a value of true, and multiple       *
*                      JMX managed bean invocations occur      *
*                      "simultaneously", then the servant      *
*                      region invocations may be skewed toward *
*                      a single servant instead of being       *
*                      randomly distributed across the set of  *
*                      available servants.                     *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
The methods invokeAnyServant and getAnyServantMBeanAttribute in
class ServantMBeanInvoker of package com.ibm.ws390.management
use a random number generator to distribute requests across the
set of available z/OS servant regions when the system property
com.ibm.websphere.management.jmx.random has a value of true.
If multiple requests were received within a narrow time window,
the generated random number was the same since the number was
generated from a new Random().  This might result in a skew
toward the same servant region being chosen from the set of
available servant regions.

Problem conclusion

The code has been modified to generate the next random number
from a static Random, ensuring that the servant region chosen
from the set of available servant regions is more randomly
distributed when multiple invocations happen "simultaneously."

APAR PK70786 currently targeted for inclusion in Service Level
(Fix Pack) 6.0.2.33 of WebSphere Application Server V6.0.1
for z/OS.

Please refer to URL:
//www.ibm.com/support/docview.wss?rs=404&uid=swg27006970
for Fix Pack availability.

Temporary fix

Comments

APAR Information

APAR number
PK70786
Reported component name
WEBSPHERE FOR Z
Reported component ID
5655I3500
Reported release
601
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2008-08-19
Closed date
2008-08-22
Last modified date
2009-03-03

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

PK75088 PK75913

Fix information

Fixed component name
WEBSPHERE FOR Z
Fixed component ID
5655I3500

Applicable component levels

R601 PSY UK43592
UP09/02/11 P F902
R610 PSY
UP

Fix is available

Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.

[{"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SS7K4U","label":"WebSphere Application Server for z\/OS"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"6.0.1","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
28 December 2021

Tips

PK70786: POOR RANDOMIZATION FOR COM.IBM.WEBSPHERE.MANAGEMENT.JMX.RANDOM

Fixes are available

Subscribe

APAR status

Closed as program error.

Error description

Local fix

Problem summary

Problem conclusion

Temporary fix

Comments

APAR Information

APAR number

Reported component name

Reported component ID

Reported release

Status

PE

HIPER

Special Attention

Submitted date

Closed date

Last modified date

APAR is sysrouted FROM one or more of the following:

APAR is sysrouted TO one or more of the following:

Fix information

Fixed component name

Fixed component ID

Applicable component levels

R601 PSY UK43592

R610 PSY

Fix is available

Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.

Document Information

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