A fix is available
APAR status
Closed as program error.
Error description
A CICS region processing JAVA/DB2 workload was suffering severe problems which lead to message DFHKE0002 A severe error (code X'0504') has occurred in module DFHKEDS. The CICS region then terminates after message DFHPC0409 XXXXXXX Abends processing abend AEXZ for the same task, transaction YYYY. The Dump showed several issues: - Loop in DFHAPLJP recovery. This happened because a task was switching back from QR TCB to the wrong T8 TCB (which was associated to another task). - The repeated AEXZ abends that bring CICS down are caused by ERM failing to change mode back to T8 after calling DB2 on L8. This causes an AEXZ abend. During that is another attempt to change back to T8 which fails again. This drives recovery in ERM again and produces another AEXZ. Third time round that loop brings CICS down.
Local fix
PTF required
Problem summary
**************************************************************** * USERS AFFECTED: All CICS users. * **************************************************************** * PROBLEM DESCRIPTION: CICS becomes unresponsive after issuing * * DFHKE0002 and DFHPC0409. * **************************************************************** * RECOMMENDATION: * **************************************************************** An application program, running on an L8 TCB, issued a LINK to a Java application program. DFHSJTH was invoked, and the task moved to a T8 TCB. The Java program made a call to a program defined as THREADSAFE and OPENAPI, and the task moved back to the L8 TCB. This request hung, and was eventually purged, destroying the L8 TCB in the process. Control returned to DFHSJTH on the T8 TCB. DFHSJTH attempted to return the task to the L8 TCB, but this was not possible because that TCB had been destroyed. The CHANGE MODE returned EXCEPTION TCB_FAILED. DFHSJTH returned to its caller, and the task remained on the T8 TCB. DFHEPC did return the task to the QR TCB, but did not fully dissociate from the T8. The task then performed other work so did not leave the system. Another task ran and got the same T8 TCB. That task also issued a LINK to a THREADSAFE OPENAPI application program, and so moved to an L8 TCB. After this call, CICS attempted to return the task to its T8 TCB, but dispatcher picked a new T8 TCB because the original one was still associated with the first task. Various errors occurred and DFHAPLJP looped in recovery (AP196C) while unstacking this task on the wrong T8 TCB: . DFHKE0002 xxxxxxxx A severe error (code X'0504') has occurred in module DFHKEDS. DFHPC0409 xxxxxxxx Abends AEXZ and AEXZ have been issued while processing abend AEXZ for the same task, transaction xxxx. . Additional keywords: msgDFHKE0002 msgDFHPC0409 KE0002 PC0409 abendAEXZ DSAT_TCB_FAILED
Problem conclusion
DFHSJTH has been updated to ensure that any failure to return to the calling TCB will cause the task to change to the QR TCB to complete the DFHSJTH cleanup. This will allow the task to correctly dissociate from the T8 TCB.
Temporary fix
********* * HIPER * ********* FIX AVAILABLE BY PTF ONLY
Comments
APAR Information
APAR number
PI53385
Reported component name
CICS TS Z/OS V4
Reported component ID
5655S9700
Reported release
700
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2015-12-02
Closed date
2016-02-05
Last modified date
2016-03-02
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
PI56041 UI35254 UI35255
Modules/Macros
DFHLEPT@ DFHSJDM DFHSJDUF DFHSJJS DFHSJSC DFHSJST DFHSJTH
Fix information
Fixed component name
CICS TS Z/OS V4
Fixed component ID
5655S9700
Applicable component levels
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.
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Document Information
Modified date:
02 March 2016