VM66334: ISFC CORRECTIVE SERVICE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• ISFC improvements to Node Table maintenance for new neighbors.
  Also, correct the return code in HCPMFNPO which may result
  in an assertion failure in the calling routine (HCPKCD).
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: z/VM systems connected via ISFC links.       *
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  * PROBLEM DESCRIPTION:                                         *
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  * RECOMMENDATION: APPLY PTF                                    *
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  Internal testing revealed base areas where improvements could be
  made as well as prevent z/VM ABENDs from occurring for
  rare timing situations in an ISFC collection.
  

Problem conclusion

• This update addresses these areas:
  
  (1) HCPACPNN is updated to address a flaw in establishing a
  new neighbor in the Node Table. In a rare case during ISFC
  collection instability, it was possible to learn just enough
  through the Link exchange to establish a new neighbor in the
  Node Table, but begin deleting that logical link before we
  could bind the NODBK and LNKBK. This left the NODBK pointing
  to the obsolete LNKBK and led to errors in processing later
  events for that node.  HCPACPNN now validates the link (LNKBK)
  before binding the NODBK and LNKBK.
  
  (2) HCPMFNPO could potentially return without setting a proper
  return code resulting in an ASSERT failure in the calling module
  Furthermore in this case the ASSERT was incorrectly requiring
  that the return code always be 0 (successful) when it was also
  possible for the return code to be 4 (ECB already posted).
  The ASSERT has also been corrected by this fix.
  

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:

  UM35570

Modules/Macros

• HCPACP   HCPKCD   HCPMFN
  

Fix information

• Fixed component name

  VM CP

• Fixed component ID

  568411202

Applicable component levels

• R710 PSY UM35570

     UP19/12/05 P 2001

Fix is available

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