PH04887: PROBLEM WITH ECB LIST WHEN EXCI JOB SENDS A CHANNEL REQUIRING 2 IRP SWITCH (SEND).

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• The EXCI job is sending a CHANNEL that is greater than 32k
  and require 2 IRP SWITCH (SEND) calls to send the data to the
  CICS region.
  
  The first SWITCH (SWITCH FIRST) is sent and then an MVS WAIT
  with an ECB list is issued waiting for the CICS region to
  return control to the EXCI job.
  
  The problem is with the ECB list used by the EXCI job.  There
  are 2 ECBs in the list and one of the hasn't been initialized.
  In this case the ECB had value x'40404040'.  When the WAIT is
  issued MVS returned control immediately to the caller, DFHXCSCR
  which continues processing.
  
  The second SWITCH (SWITCH SUBSEQUENT) is issued by DFHXCPRH.
  DFHIRP rejects the SWITCH with return code x'0000008C',
  IRERRNSW, because control is on the other side.
  
  This results in the DPL request failing with EXCI_SYSTEM_ERROR
  (16) IRP_SWITCH_PULL_FAILURE (616) SUB_REASON1 : 00000140
  SUB_REASON2 : 00000000 in the EXCI region and the mirror task
  abending AITI in the CICS region.
  

Local fix

• NA
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: An EXCI client program that specified a *
  *                      CHANNEL on a DPL request where the      *
  *                      CHANNEL data, FMHs, CHANNEL and         *
  *                      CONTAINER headers exceed 32K may fail   *
  *                      with response and reason codes,         *
  *                      EXCI_SYSTEM_ERROR (16)                  *
  *                      IRP_SWITCH_PULL_FAILURE (616)           *
  *                      SUB_REASON1 : 00000140                  *
  *                      SUB_REASON2 : 00000000.                 *
  *                      and message, DFHEX0002 A severe error   *
  *                      (code X'0616') has occurred             *
  *                      in module DFHXCPRH.                     *
  ****************************************************************
  An EXCI client program specifies a CHANNEL greater than 32K
  on a DPL request. Because the DPL data is greater than 32K,
  DFHXCSCR issues a DFHIRP SWITCH FIRST to send the first part
  of the request. An MVS WAIT is issued using an ECB list that
  contains 2 ECBs, WS_TIMER_ECB and SLCBLECB, to wait for the
  server region to return control to the EXCI region.
  Before the MVS WAIT is issued, the SLCBLECB is initialised to
  x'00000000'. The WS_TIMER_ECB is not initialised and depending
  on its value, the MVS WAIT may return control to DFHXCSCR
  immediately. In the customer case the value was x'40404040',
  indicating that the WS_TIMER_ECB has been posted.
  DFHXCSCR continues processing and returns to DFHXCPRH to send
  the remaining CHANNEL data. A DFHIRP SWITCH SUBSEQUENT is issued
  and gets rejected by DFHIRP with a return code of x'0000008C',
  IRERRNSW, because control is on the other side.
  The DPL request fails with response and reason codes,
  EXCI_SYSTEM_ERROR (16), IRP_SWITCH_PULL_FAILURE (616)
  SUB_REASON1 : 00000140, SUB_REASON2 : 00000000.
  Message, DFHEX0002 A severe error(code X'0616') has occurred
  in module DFHXCPRH, is issued.
  In the server region that server program abends AITI.
  
  Additional keywords: MSGDFHEX0002 EX0002 abendEX0002 abendAITI
  

Problem conclusion

• DFHXCSCR has been changed to initialise WS_TIMER_ECB with
  x'00000000' before issuing the MVS WAIT macro.
  

Temporary fix

Comments

APAR Information

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

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

  UI60925 UI60926

Modules/Macros

• DFHAPCR  DFHXCSCR
  

Fix information

• Fixed component name

  CICS TS Z/OS V5

• Fixed component ID

  5655Y0400

Applicable component levels

• R100 PSY UI60925

     UP19/01/29 P F901

• R200 PSY UI60926

     UP19/01/26 P F901

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.