PK48845: DFHME0121 ISSUED FOR DFHIR3783, BUT HEADER INSERTION CONTAINS BAD DATA

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• DFHMEME is called to issue a macro to fill in inserts for
  generating message DFHIR3783. The macro expansion moved data in
  a third pararameter, INSERT3(ME_IN3_P,ME_IN3_N). DFHZIS2 is
  passing the inserts to DFHMEME for building the message with the
  transid, termid, and message number for DFHIR3783. The
  application data is so large, 32K, that a second ZIS2 RECEIVE
  needs to be issued. In the second RECEIVE the second byte of
  data happens to be x'07'. DFHZARQ thinks that it has received
  an FMH7, and it calls DFHZIS2 to RECEIVE ABORT, which tried to
  issue a message based on the information received. The result
  could be unpredictable since this is application data. In the
  customer case, this resulted in message DFHME0121 and an SDUMP
  being taken.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: Message DFHIR3783 erroneously           *
  *                      produced when user data from            *
  *                      a DPL request with Channel data         *
  *                      contains x'07' at start of the          *
  *                      final buffer.                           *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  An application program issues an EXEC CICS LINK request with the
  CHANNEL option to a program in a remote region.
  Because the data contained in the Channel is very large (>32k)
  the first buffer containing the FMHs and start of the data is
  sent by DFHAPCR as part of the DFHTC TYPE=WRITE with the FMH
  option.
  
  On return to DFHISP the final buffer containing the end of the
  Channel data is sent as part of normal ISP's Converse function.
  This results in another DFHTC TYPE=WRITE request which
  incorrectly has the FMH option set.
  
  When the final buffer is received in the partner region, as it
  contains the FMH option and the user data just happens to
  include a x'07' in position 2 of the TIOA, DFHZARQ assumes that
  this is an ABORT request (FMH07).
  
  The partner region then attempts to issue message DFHIR3783,
  which may or may not fail (DFHME0121) when trying to build the
  message from the rest of the data.
  The mirror transaction in the partner region abends AITI and
  then replies to what it thought was the Abort request before
  terminating.
  
  The sender of the DPL request receives the Abort request back to
  its send of the final buffer and starts to abend this
  transaction. However when DFHCRIU's PERFORM_COMMIT attempts to
  acknowledge the Abort request, the partner task has finished
  leaving this task in an IRLINK wait indefinitely.
  
  Additional keywords
  msgDFHIR3783 msgDFHME0121 EXPORT_ALL transmit_buffer CONV1500
  

Problem conclusion

• DFHAPCR has been amended to indicate (TCTE_CHAN_SENT_FMH) in the
  session TCTTE whether or not the first buffer has been sent
  containing the FMH data. DFHISP has also been amended to issue
  the DFHTC TYPE=WRITE without the FMH option if this indicator is
  on.
  
  This will mean that DFHZARQ in the partner region will no
  longer look for a x'07' in the TIOA as the FMH indicator will
  now be off.
  
  
  The documentation in the following manual has been changed :-
  
  CICS Transaction Server for z/OS
  Version 3 Release 2
  CICS Data Areas
  Document Number GC34-6863-00
  
  Change Section 1.196 - TCTTE Terminal Entry
  (90)   BIT(8)          1    TCTTECHN   - Channel properties
  replace :-
     1...  ....       TCTECHAN           - Other end of MRO link
                                           supports channels
     .1..  ....       TCTEEWLM           - supports EWLM
                                           correlators
     ..11  1111       *                  - Reserved
  
  with  :-
     1...  ....       TCTECHAN           - Other end of MRO link
                                           supports channels
     .1..  ....       TCTEEWLM           - supports EWLM
                                           correlators
     ..1.  ....       TCTE_CHAN_SENT_FMH - FMH sent by DFHAPCR
     ...1  1111       *                  - Reserved
  

Temporary fix

• FIX AVAILABLE BY PTF ONLY
  

Comments

APAR Information

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

  PK35533

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

  UK28713

Modules/Macros

•    DESAPCR  DFHAPCR  DFHISP   DFHTCTTE DFHTCTZE
  

Fix information

• Fixed component name

  CICSTS V3 Z/OS

• Fixed component ID

  5655M1500

Applicable component levels

• R500 PSY UK28713

     UP07/09/06 P F709

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.