VM66218: SOFT ABEND DUMPS HAVE PAGES MISSING

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• In some cases, pages pointed to by general registers are not
  included in soft abend dumps.
  This missing data makes it difficult to debug problems.
  

Local fix

• N/A
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of z/VM                            *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  ****************************************************************
  * RECOMMENDATION: APPLY PTF                                    *
  ****************************************************************
  During soft abend dump processing, HCPABHAR calls HCPABHAL to
  add the pages to the dump that are pointed to by the registers
  at the time of failure.  The problem can occur when the code in
  HCPABHAL is processing registers and handling them as if they
  contain logical addresses.  In addition to adding the page to
  which each register points, HCPABHAL also attempts to add the
  pages before and after that page.  It verifies that these
  additional pages are dumpable by doing a LRAG instruction to
  get a real address in order to validate the logical address
  before adding them to the Dump Page List.  The problem is that
  even though the page to which the register points is valid, the
  page before it is not.  If the LRAG instruction above label
  HRADDR2 fails, the code incorrectly branches to LOOPREGN to
  advance to the next register.  That's wrong --- it should
  instead branch to LOOPADRN to just skip the invalid page and
  attempt to add the page pointed to by the register.
  

Problem conclusion

• In three places in HCPABH after label LOOPADR, the code has
  been changed to branch to LOOPADRN instead of LOOPREGN.  Also,
  code above label LOOPADR has been changed to be more obvious
  in how it sets up the loop control registers.  Also, various
  comments throughout this section of code have been changed to
  be more accurate and informational.
  
  Also some other problems in the soft abend dump code will be
  fixed with this Apar.
  
  -  During soft abend initialization, the code in HCPABN intends
     to clear the Soft Abend Common area (SABCM).  But the
     instruction incorrectly loads the length of the area to
     clear and loads a zero from the prefix page.  Changing the
     instruction from a "L" to "LA" fixes the problem.
  
  -  In HCPABS, during soft abend initialization, code was added
     in HCPABSIN to clear the Dump Page List.  The list could
     contain data from the previous soft abend dump and is
     confusing while debugging the code.
  
  -  In HCPABF, code after label WRTCT that initializes the
     address of the last item in the Correlation Table Page list
     could be wrong if the size of the list is increased.  The
     code has been changed to use arithmetic instructions rather
     than a "LA" instruction.  Also in HCPABF, two places in the
     code after label ADDDPL, a "LLGTR" instruction was added to
     clear the high half of R3 because it is used as the SATBK
     base register in a MVC instruction while in 64 bit mode.
  

Temporary fix

• FOR RELEASE VM/ESACP/ESAR710 :
  PREREQ: NONE
  CO-REQ: NONE
  IF-REQ: NONE
  

Comments

APAR Information

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

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

  UM35493

Modules/Macros

• HCPABF   HCPABH   HCPABN   HCPABS
  

Fix information

• Fixed component name

  VM CP

• Fixed component ID

  568411202

Applicable component levels

• R710 PSY UM35493

     UP19/07/31 P 1902

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.