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APAR status

  • Closed as program error.

Error description

  • when freeing a large message buffer, module DSIFMSGM calls the
    DSIFRE macro with length specified (R2->HDRBLENG). The compiled
    code executes a load halfword into the parm list for the call to
    module DSIFMN. Because the length of the storage is x'B1BC' this
    causes the length parm to contain FFFFB1BC due to the high order
    bit of the halfword being on. When DSIFMN adds this negative
    length to the storage address to verify the overlay detection
    field, it addresses unavailable storage causing the abend0c4.
    There may be other symptoms of this problem such as incorrect
    overlay detection abends.

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All users of remote operations               *
    *                 (RMTCMD) in Tivoli NetView for z/OS          *
    * PROBLEM DESCRIPTION: When RMTCMD is invoked with a very      *
    *                      large command to be sent to a NetView   *
    *                      domain, particularly over IP, whether   *
    *                      that is in an IPv4 or IPv6 network, an  *
    *                      x'0C4' abend can occur for task DSIUDST *
    *                      in module DSIFMN.  Also, the following  *
    *                      message may appear in the NetView log:  *
    *                      DWO050E FOR PROBLEM DEBUG:  COMPONENT:  *
    *                      UDST  MODULE: DSIUDRSP  RC: 16 COMMAND  *
    *                      PROCESSOR DRIVEN INCORRECTLY            *
    *                      Additional search keywords:  ABEND0C4   *
    *                      ABENDS0C4 msgDWO050E                    *
    * RECOMMENDATION:                                              *
    When RMTCMD determines it will use a transport, perhaps SNA
    LU6.2 or TCP/IP (IP) services, to send a command to a NetView
    domain, it "linearizes" the command and associated buffers.  In
    that "linearization" process, a buffer is obtained and
    essentially two copies of the command are placed in it.  The
    second copy is created for compatibility with a down-level
    NetView release.  For RMTCMD over IP (IPv4 or IPv6 networks), in
    particular, this buffer gets copied to a NetView-format buffer
    for transport to the DSIUDST task, which manages the TCP
    connection with a target NetView domain.
    When the command to be sent to the target NetView domain is
    large (> 15600 bytes), and the two copies are made, the length
    of the buffer plus the length of the buffer header for the
    NetView-format buffer exceeds 32767 bytes, the largest positive
    value that HDRBLENG in the buffer header supports, yet the
    storage is obtained and HDRBLENG is set, anyway.  This makes
    HDRBLENG a negative value.
    When the DSIUDRSP command, running on the DSIUDST task,
    processes this data, it detects bad length information in the
    buffer and writes the DWO050E message to the NetView log.
    When the buffer is to be freed, NetView's buffer freeing
    service uses that negative length on a DSIFRE request to free
    the storage.  When that negative length is added to the storage
    address to determine the location of a pattern area to be
    checked for a storage overlay, DSIFMN abends x'0C4', because
    the address is now bad.

Problem conclusion

  • Part DSIUSNAM is being changed to ensure the length of the
    command to be sent to the target NetView domain is not longer
    than 15200 bytes.  If a command longer than 15200 bytes is
    provided on RMTCMD SEND, regardless of whether the transport
    services to be used are SNA LU6.2 or IP, message DSI076I COMMAND
    TEXT TOO LONG will be issued and RMTCMD will fail without
    sending the command anywhere.
    Part DSIUSNDM is being changed to ensure that, following the
    determination that the RMTCMD-invoking operator in the local
    NetView domain is to execute the command provided with RMTCMD,
    and therefore, no SNA LU6.2 or IP transport services are being
    used, it does not free the buffer containing the original
    RMTCMD command prior to copying command data from it.
    The help for RMTCMD (part EUYRMCMD) is being updated to
    describe the limitation regarding size of the command to be
    sent to a remote NetView domain.  Under the description of
    "command", the following paragraph is to be added:
    "The maximum length of a command string to be transported to a
    NetView domain by RMTCMD is 15200 bytes."
    The same change should be made to the RMTCMD (NCCF) command
    description in IBM Tivoli NetView for z/OS Command Reference
    Volume 2 (O-Z), SC31-8858-04.
    The help for message DSI076I (part DSI07) is being updated
    to describe its possible appearance for RMTCMD with this
    list item (remembering that the list is introduced with
    "You entered one of the following:"):
    "Command and parameters longer than 15200 characters to be
    transported to a NetView domain by RMTCMD"
    The same change should be made to the message DSI076I
    description in IBM Tivoli NetView for z/OS Messages and Codes
    Volume 1 (AAU-DSI), SC31-6965-04.
    Also, in the online help (but not necessary for the manual),
    the alignment of the continuation line for the second list
    item ("VTAM command ...") is being fixed.

Temporary fix


APAR Information

  • APAR number


  • Reported component name


  • Reported component ID


  • Reported release


  • Status


  • PE




  • 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:

    OA42176 UA69044 UA69045 UA69046



Publications Referenced
SC31885804 SC31696504      

Fix information

  • Fixed component name


  • Fixed component ID


Applicable component levels

  • R54B PSY UA69044

       UP13/06/01 P F305

  • R54E PSY UA69045

       UP13/06/01 P F305

  • R54J PSY UA69046

       UP13/06/01 P F305

Fix is available

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Document information

More support for: Tivoli NetView for z/OS

Software version: 54B

Reference #: OA41592

Modified date: 03 June 2013

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