PI65465: FORCEPURGE OF A TASK CAUSES AEXZ ABEND LOOP

Obtain the fix for this APAR.

APAR status

• Closed as unreproducible in next release.

Error description

• A task has entered the system, running a Java program
  on a T8 TCB. A PURGE_TRANSACTION FORCE request was
  issued against this task. At the time this occurred, T8
  was processing a DB2 request, under the control of
  DFHD2D2, though I suspect that the TCB was over in DB2
  at the time of the purge. As part of the purge request,
  T8 has been made unusable.
  DFHD2D2 initiates an abend, and percolates that up
  through DFHD2EX1 to DFHERM. Cleanup is completed, and
  DFHERM exits the recovery environment and attempts to
  change back to the caller's TCB (T8). This fails because
  that TCB is no longer available, which leads to the loop
  of AEXZ abends. Each time round the loop we exit recovery,
  and attempt to switch back to T8, resulting in a new AEXZ abend.
  .
  Additional symptoms / keywords:
  CICS takes a KERNDUMP and abends after DB2 is cancelled. The
  dump shows an L8 TCB associated with a task doing DB2 work
  was abended with 04E, reason code 00F30011 indicating that DB2
  was not active. During retry of the 04E abend, the QR TCB also
  issued an abend 999 or x'3E7', targeting the L8 TCB. This would
  be the CDBF task trying to purge all remaining tasks that had
  been active in DB2. Because this is a recursive error for this
  TCB, DFHKESTX chooses to abend CICS.
  KTCB_KESTX_IN_PROGRESS 3E7 abend40E S40E abendS40E abend999
  

Local fix

• *
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS Users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: Loop of AEXZ abends from DFHERM         *
  *                      after a purge of a Java transaction     *
  *                      while accessing DB2.                    *
  ****************************************************************
  * RECOMMENDATION: .                                            *
  ****************************************************************
  A user task is running in a JVM server in CICS on a T8 TCB.
  It makes a data base request to DB2 using JDBC. The task
  remains on the T8 TCB to perform the interaction with DB2,
  and while this is occurring, a CICS Task PURGE is issued
  for this task.
  .
  DFHERM sets the task to ABTERM_ALLOWED before calling DB2,
  so the CICS dispatcher performs the PURGE using CALLRTM.
  The CICS ESTAE (DFHKESTX) is driven for the T8 TCB.
  The abend does not allow retry, so the task is moved from
  the T8 TCB to the QR TCB in order that the task can begin
  abend processing, and the T8 TCB can terminate.
  The T8 TCB is marked unusable.
  .
  Now running on the QR TCB, the task runs the recovery
  routines for DFHD2D2, DFHD2EX1, and DFHERM.
  DFHERM exits the recovery environment, then attempts
  to switch back to the original (T8) TCB.
  This TCB is no longer available.
  This generates a new AEXZ abend, and re-enters the DFHERM
  recovery routine. DFHERM becomes trapped in a loop,
  continually issuing AEXZ abends.
  Eventually the region will become short on storage.
  .
  Additional Keywords: DFHSM0133 abendAEXZ TCB_FAILED AD2R
  AP 319D D2EX1 *EXC* THREAD TCB HAS ABENDED WITH ABEND 000003E7
  AP 2535 ERM   *EXC* DSAT-CHANGE-MODE-FAILED
  

Problem conclusion

Temporary fix

Comments

• DFHERM has been updated to avoid the loop of AEXZ abends
  when the application was running on a T8 TCB, and that
  TCB is no longer available.
  Furthermore, the CICS Java domain has been updated so that
  after a T8 TCB terminates unexpectedly, CICS is able to
  run recovery for the abending task under the QR TCB.
  CICS will then terminate and automatically restart
  the JVM server.
  Message DFHSJ1007 will be issued to notify the user of the
  JVM server restart.
  .
  The CICS Transaction Server for z/OS Version 5 Release 2
  'CICS Messages and Codes Vol 1' manual (GC34-7283-00)
  will be updated after 'DFHKEnnnn messages' with a new message:
  DFHKE0996 applid DFHKESTX DRIVEN FOR CANCEL WHILE PERFORMING
  RETRY.   COMPLETION CODE code ON TCB tcb.
  Explanation: MVS has issued a cancel abend against this TCB
  while CICS was attempting to locate the retry point for an
  earlier, retryable abend.
  User Response: None.
  CICS Response: This TCB will be terminated.
  .
  The CICS Transaction Server for z/OS Version 5 Release 3
  'CICS Messages and Codes Vol 1' manual (GC34-7418-00)
  will be updated after 'DFHKEnnnn messages' with a new message:
  DFHKE0996 applid DFHKESTX DRIVEN FOR CANCEL WHILE PERFORMING
  RETRY.   COMPLETION CODE code ON TCB tcb.
  Explanation: MVS has issued a cancel abend against this TCB
  while CICS was attempting to locate the retry point for an
  earlier, retryable abend.
  User Response: None.
  CICS Response: This TCB will be terminated.
  

APAR Information

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

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

  UI48213 UI48214 UI48215 UI48216 UI48217 UI48218 UI48219 UI48220

Modules/Macros

• DFHABAB  DFHAPJVM DFHAPLI1 DFHAPLI2 DFHAPLI3 DFHAPLJ1 DFHAPLJP
  DFHAXIS2 DFHCDJNI DFHCDK64 DFHCDKRN DFHCPI   DFHEIG   DFHEIP
  DFHERM   DFHKEDS  DFHKERN  DFHKESTX DFHKETCB DFHLONGN DFHMEKEC
  DFHMEKEE DFHMEKEK DFHMSG64 DFHMSGIF DFHSJBD  DFHSJDM  DFHSJDS
  DFHSJDST DFHSJDUF DFHSJIN  DFHSJINT DFHSJIS  DFHSJJS  DFHSJL
  DFHSJPTI DFHSJRL  DFHSJSA  DFHSJSC  DFHSJST  DFHSJTH  DFHSJTRI
  DFHSJXM  DFHTRC64 DFHTRCIF DFHWS002 DFHWS003 DFHWS004 DFHWS005
  DFHWS006 DFHWS007 DFHWS008 DFHWS009 DFHWS010 DFHWS011 DFHWS012
  DFHWS013 DFHWS014 DFHWS015 DFHWS016 DFHWS017 DFHWS018 DFHWS019
  DFHWS020 DFHWS021 DFHWS022 DFHWS023 DFHWS024 DFHWS025 DFHWS026
  DFHWS027 DFHWS028 DFHWS029 DFHWS030 DFHWS031 DFHWS032 DFHWS033
  DFHWS034 DFHWS035 DFHWS036 DFHWS037 DFHWS038 DFHWS039 DFHWS040
  DFHWS041 DFHWS042 DFHWS043 DFHWS044 DFHWS045 DFHWS046 DFHWS047
  DFHWS048 DFHWS049 DFHWS050 DFHWS051 DFHWS052 DFHWS053 DFHWS054
  DFHWS055 DFHWS056 DFHWS057 DFHWS058 DFHWS059 DFHWS060 DFHWS061
  DFHWS062 DFHWS064 DFHWS065 DFHWS066 DFHWS068 DFHWS069 DFHWS070
  DFHWS071 DFHWS072 DFHWS073 DFHWS074 DFHWS075 DFHWS076 DFHWS077
  DFHWS078 DFHWS079 DFHWS081 DFHWS082 DFHWS083 DFHWS084 DFHWS085
  DFHWS086 DFHWS087 DFHWS088 DFHWS089 DFHWS090 DFHWS091 DFHWS092
  DFHWS122 DFHWS123 DFJ@H356 DFJ@H360 DFJ@H427 DFJ@H467 DFJ@H468
  DFJDTCOE DFJOUTRE DFJWLPPL
  

Fix information

• Fixed component name

  CICS TS Z/OS V5

• Fixed component ID

  5655Y0400

Applicable component levels

• R000 PSY UI48217

     UP17/07/20 P F707

• R003 PSY UI48220

     UP17/07/21 P F707

• R00D PSY UI48218

     UP17/07/20 P F707

• R00W PSY UI48219

     UP17/07/20 P F707

• R900 PSY UI48213

     UP17/07/20 P F707

• R903 PSY UI48216

     UP17/07/20 P F707

• R90D PSY UI48214

     UP17/07/20 P F707

• R90W PSY UI48215

     UP17/07/20 P F707

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.