PM57513: ABEND4C5 RC742E0402 IN MODULE EZBIPRHD 12/02/06 PTF PECHANGE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• ABEND4C5 rc742E0402 in EZBIPRHD due to a RTOP with an
  unbalanced RtpRteCount and RtpUseCount.  The RTOP RtpRteCount
  is zero and the RtpUseCount is 2 indicating something is wrong
  in the referencing of the RTOP.
  The problem stems from the removal of a destination cache
  entry in the routing tree.  A timing condition exists where
  the destination cache entry is being removed at the same
  time that it is located and referenced for reuse.
  Destination cache entries are created for IPv6 network
  traffic and IPv4 when PATHMTUDISCOVERY or VIPAROUTE are
  enabled.
  

Local fix

• Disable PATHMTUDISCOVERY on the IPCONFIG statement in the
  TCP/IP profile.  This can be done dynamically using the
  VARY TCPIP,tcpname,Obeyfile,datasetname   command where
  the dataset contains:
    IPCONFIG NOPATHMTUDISCOVERY
  
  Disable VIPAROUTE on the VIPADYNAMIC block in the TCP/IP
  profile.  This can be done dynamically using the
  VARY TCPIP,tcpname,Obeyfile,datasetname   command where
  the dataset contains:
    VIPADYNAMIC
      VIPAROUTE DELETE dynxcfip target_ipaddr
    ENDVIPADYNAMIC
  
  The removal of VIPAROUTE will cause any distributed traffic
  to be forwarded over internal XCF or IQDIO links.
  
  ADDITIONAL SYMPTOMS:
  ABEND0C4 in EZBIPRTE caused by the routing tree becoming
  corrupted.
  
  ABEND4C5 EZBXFUT3 Reason 77BB0402
  .
  ABEND0C4 in EZBIPRHD - PTREEPOINTUP
  ABEND0C4 in EZBIPRHD
  
  ABEND4C5 RC 76803003 - TcpSTKPTreeRecover
  
  ABEND4C5 RC 74BE2506 - TcpitStorNotAllocated
  
  ABEND0C4 in EZBXFMS6 during TERMCONN processing due to an
  invalid XFCRHTE_RTE pointer.  The TERMCONN processing is
  identifying the CRHTE to be removed and the CRHTE address
  is bad.
  
  KEYWORDS:
  AB4C5 ABs4C5 ABENDs0C4 4C5 0C4 rc76803003 3003 742E0402
  0402 TcpUnexpectedErr PATHMTUDISCOVERY VIPAROUTE
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of the IBM Communications Server   *
  *                 for z/OS Version 1 Release(s) 11, 12,        *
  *                 and 13 IP                                    *
  ****************************************************************
  * PROBLEM DESCRIPTION: Various abends in route management      *
  *                      modules accessing a route that has been *
  *                      deleted.  Abends may also occur in      *
  *                      modules unrelated to route management   *
  *                      due to possible storage corruption.     *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  Various abends in route management modules accessing a route
  that has been deleted.  Abends may also occur in modules
  unrelated to route management due to possible storage
  corruption.
  
  Destination cache entries are special purpose structures added
  to the routing trees for IPv6 traffic, and IPv4 traffic when
  PathMTUdiscovery is enabled, or VIPAROUTE is enabled for
  Sysplex distributor.  A garbage collection routine periodically
  runs and deletes any stale destination cache entries that are
  no longer in use.  The delete occurs in the update copy of the
  routing tree, then the search copy of the routing tree.  The
  reference count maintained in the destination cache entry is
  incorrectly decremented before the entry has been removed from
  the search tree.  A timing window exists where a searcher can
  find the deleted destination cache entry and use it after the
  associated storage has been returned to the storage cache queue
  for reuse.  The searcher will update the reference count and
  when the destination cache is no longer needed it will decrement
  the reference count.  The storage where the destination cache
  entry resided may be used for another route structure or any
  other storage request that has a similar size.
  The reference count update logic may detect an error condition
  and generate an ABEND4C5 in one of the routing modules, or the
  update may be performed without detecting an error with
  unpredictable results.
  
  The final reference to the destination cache entry should not
  be removed until the trees have been swapped and the search
  tree has been updated.
  +-------------------------------------------------------------+
  + 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

• EZBIPDDC and EZB6PDDC have been amended to maintain a reference
  count on deleted destination cache entries until the routing
  trees have been successfully swapped.
  
  * 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:

  UK76838 UK76839 UK76840

Modules/Macros

• EZBIPRTE EZB6PRTE
  

Fix information

• Fixed component name

  TCP/IP V3 MVS

• Fixed component ID

  5655HAL00

Applicable component levels

• R1B0 PSY UK76838

     UP12/04/03 P F204 ®

• R1C0 PSY UK76839

     UP12/04/03 P F204 ®

• R1D0 PSY UK76840

     UP12/04/03 P F204 ®

Fix is available

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