PM68797: Deadlock in JSMessageData.lazyCopy()

Fixes are available

APAR status

Closed as program error.

Error description

A dead lock can occur from within the MFP layer of SIB
JSMessageData.lazyCopy.
.

Javacore Output:
.
1LKDEADLOCK    Deadlock detected !!!
NULL           ---------------------
NULL
Thread "JS-ReceiveListenerDispatcher:4292"(0x000000001D75ED00)
is waiting for:
sys_mon_t:0x0000004A84837600 infl_mon_t: 0x0000004A84837670:
com/ibm/ws/sib/mfp/jmf/impl/JSMessageImpl@0x00000000B92E9108/
0x00000000B92E9114:
which is owned by:
Thread "Consumer cl_appIS1P_prod.000-SCA.SYSTEM.WPP04.
Bus :  1244" (0x000000001CECE200)
which is waiting for:
sys_mon_t:0x000000493F590D80 infl_mon_t: 0x000000493F590DF0:
com/ibm/ws/sib/mfp/jmf/impl/JSMessageImpl@0x00000000B9202360/
0x00000000B920236C:
which is owned by:
Thread "JS-ReceiveListenerDispatcher:4292"(0x000000001D75ED00)


Following is the stacktrace of both the threads.
.
com/ibm/ws/sib/mfp/jmf/impl/JSMessageData.lazyCopy(JSMessageData
.java:1194)
com/ibm/ws/sib/mfp/jmf/impl/JSVaryingListImpl.getCopy(JSVaryingL
istImpl.java:212)
com/ibm/ws/sib/mfp/jmf/impl/JSListCoder.copy(JSListCoder.java:14
3)
com/ibm/ws/sib/mfp/jmf/impl/JSField.copyValue(JSField.java:269)
com/ibm/ws/sib/mfp/jmf/impl/JSMessageData.copyCache(JSMessageDat
a.java:1120)
com/ibm/ws/sib/mfp/jmf/impl/JSMessageData.getInternal(JSMessageD
ata.java:546)
com/ibm/ws/sib/mfp/jmf/impl/JSMessageData.getValue(JSMessageData
.java:489)
com/ibm/ws/sib/mfp/jmf/impl/JSMessageImpl.getValue(JSMessageImpl
.java:1132)
com/ibm/ws/sib/mfp/impl/JsMsgPart.getField(JsMsgPart.java:99)
..
..
..

Local fix

Problem summary

****************************************************************
* USERS AFFECTED:  Users of the default messaging provider     *
*                  for IBM WebSphere Application Server        *
*                  versions 7.0, 8.0 and 8.5.                  *
****************************************************************
* PROBLEM DESCRIPTION: Deadlock is detected in                 *
*                      JSMessageData.lazyCopy().               *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
Deadlock is detected in JSMessageData.lazyCopy() because of the
"shared cache" which shares JSMessageData instances between
threads.
The lazyCopy() operation access two JSMessageData objects
which are source and target. In a deadlock scenario, for
thread1, JSMessageData1 acts as a source and JSMessageData2 as
a target. At the same time, for thread2, JSMessageData2 acts
as a source and JSMessageData1 as a target.
Thread1:
--------
Operation: lazyCopy
Acquired lock on: JSMessageData1
Waiting to acqruire lock on: JSMessageData2
Thread2:
--------
Operation: lazyCopy
Acquired lock on: JSMessageData2
Waiting to acqruire lock on: JSMessageData1
The deadlock stacktrace is as follows.
com.ibm.ws.sib.mfp.jmf.impl.JSMessageData.lazyCopy()
com.ibm.ws.sib.mfp.jmf.impl.JSVaryingListImpl.getCopy()
com.ibm.ws.sib.mfp.jmf.impl.JSListCoder.copy()
com.ibm.ws.sib.mfp.jmf.impl.JSField.copyValue()
com.ibm.ws.sib.mfp.jmf.impl.JSMessageData.copyCache()
com.ibm.ws.sib.mfp.jmf.impl.JSMessageData.getInternal()
com.ibm.ws.sib.mfp.jmf.impl.JSMessageData.getValue()
com.ibm.ws.sib.mfp.jmf.impl.JSMessageImpl.getValue()
com.ibm.ws.sib.mfp.impl.JsMsgPart.getField()
..
..

Problem conclusion

The fix is to do copyCache() operation (which in-turn calls
lazyCopy()) on JSMessageData before adding JSMessageData
object in to the shared cache and accessible for other threads.

The fix for this APAR is currently targeted for inclusion
in fix packs 7.0.0.27, 8.0.0.6 and 8.5.0.2.

Please refer to the Recommended Updates page fordelivery
information:
http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980

Temporary fix

Comments

APAR Information

APAR number
PM68797
Reported component name
WAS SIB & SIBWS
Reported component ID
620800101
Reported release
300
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2012-07-13
Closed date
2013-02-28
Last modified date
2013-06-12

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
WAS SIB & SIBWS
Fixed component ID
620800101

Applicable component levels

R800 PSY
UP

[{"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SSEQTP","label":"WebSphere Application Server"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"7.0","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
29 October 2021

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PM68797: Deadlock in JSMessageData.lazyCopy()

Fixes are available

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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

R800 PSY

Document Information

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