PQ77933: NUMEROUS ABENDS IN SYSPLEX AFTER OBEYFILE WITH INVALID HOME LIST

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• A VARY TCPIP,,OBEYFILE,dsn command is issued for one of the
  TCPIP stacks in a SYSPLEX.  If the file causes all of the
  entries in that stack's HOME list to be deleted, an incorrect
  XCF update message can be sent to all of the other stacks in
  the SYSPLEX.  The systems receiving that message will try to
  interpret it as a large list if IP addresses to be processed.
  In consolidating the old and 'new' lists, it will overlay
  various words with 0s (starting in the message's location in
  ECSA and continuing upward from there).  The size of the area
  that gets these overlays depends on the values at location 4 on
  the sending system (this will tend to be much larger if it is
  running in ESA mode).  Results of these overlays are
  unpredictable, but will probably include numerous ABENDs like
  S0C1 (both from trying to execute a location with zeroes and
  from branching using a pointer that is zero), S0C4, and S378.
  On a busy system or one where ESA mode is used, the number of
  ABENDs will likely overwhelm the affected systems causing SQA,
  CSA and Aux storage exhaustion with resultant outages.
  
  Other Symptoms:
  
  Examination of SYSTRACE for the affected systems will show
  numerous SSRV 132 entries for an SRB in the TCPIP address space
  for 32 (x'20') bytes of SP241K6 (ECSA).  Examination of the
  storage areas for these locations will have the following
  pattern:
     +00   aaaaaaaa   00000000   00000010   06F1019F
     +10   nnnnnnnn   bbbbbbbb   pppppppp   80000000
  where pppppppp points to the XCF Partner (XFPT) entry for the
  sending system (where the OBEYFILE was issued).   For this
  XFPT, +10 will have the system name and +20 will have the TCPIP
  job name of the sending stack.
  
  DUAF report for an affected stack will show a DUCB that is
  running EZBXFMSI (this will either be still in use or may
  have ABENDed).  The MsgPtr variable value will point to a
  16 byte area whose first 8 bytes will match locations 0-7
  of the sending system.
  

Local fix

• Systems affected by this will need to be re-IPLed to clear up
  the overlaid storage.
  
  This scenario can be avoided by defining one or both of the
  following on each stack in the sysplex:
    - A DYNAMIC XCF address for the stack.  This is specified via
      the DYNAMICXCF keyword on the IPCONFIG statement of the
      TCPIP profile.
    - At least one DVIPA address.  This is specified via the
      VIPADYNAMIC statement in the TCPIP profile.  This address
      does not have to be activated.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of the Communications Server for   *
  *                 OS/390 Release 10 IP and z/OS Version 1      *
  *                 Release 2, 4 & 5 IP                          *
  ****************************************************************
  * PROBLEM DESCRIPTION: Multiple abends, low core overlays and  *
  *                      Sysplex Wide outages can occur when a   *
  *                      zero length IP Table is generated and   *
  *                      distributed within Sysplex XCF partner  *
  *                      messaging.                              *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  During obeyfile processing an invalid IpTable pointer is used if
  an IpTable fails to be generated due to a storage allocation
  failure or a delete of all stack IP Addresses. This occurs
  because an old IpCount value is used but the pointer to the
  IpTable is 0. The invalid 0 pointer is assumed to be a pointer
  to the IpTable and is sent to all Sysplex Partners. When
  received by the partners, the fields which should have been
  IpTable size and IpCount are invalid and result in multiple
  abends and overlays. The sending side may attempt to write to
  storage using the invalid 0 pointer and overlay low core
  storage.
  +-------------------------------------------------------------+
  + Please check our Communications Server for OS/390 homepages +
  + for common networking tips and fixes.  The URL for these    +
  + homepages can be found in Informational APAR II11334.       +
  +-------------------------------------------------------------+
  

Problem conclusion

• Code to build the ip table has been updated to validate both
  the IpTable pointer and the IpCount.
  
  * Cross Reference between External and Internal Names
  

Temporary fix

• *********
  * HIPER *
  *********
  

Comments

APAR Information

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

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

  UQ80383 UQ80384 UQ80385 UQ80386

Modules/Macros

• EZBXFMSO
  

Fix information

• Fixed component name

  TCP/IP V3 MVS

• Fixed component ID

  5655HAL00

Applicable component levels

• R120 PSY UQ80383

     UP03/10/17 P F310 Ž

• R140 PSY UQ80384

     UP03/10/17 P F310 Ž

• R150 PSY UQ80385

     UP03/10/16 P F310 Ž

• R50A PSY UQ80386

     UP03/10/17 P F310 Ž

Fix is available

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