PH44744: MQ Z/OS: ABEND0C4 OCCURRED IN CSQWDSD0 AFTER CLAIMING THE SCOMDUMP WORK AREA, PREVENTING A DUMP FOR 22/03/29 PTF PECHANGE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• CICS jobs and the CHIN received storage-related abends due to
  private shortage in the MSTR.  Many of them did not cause a
  dump until the CHIN took one for 5C6-00E7014F.
  The 5C6-00E7014F abend occurred for a dispatcher TCB because an
  adapter TCB abended 5C6-00E20015. Logrec shows many
  5C6-00E20015 and 878 abends (ABEND878).
  The 5C6-00E20015 and 878 abends are occurring for storage
  requests for SP 229, key 7 storage (SP229 KEY7). The majority of
  the 5C6-00E20015 abends are for application (and CHIN adapter)
  tasks trying to allocate an SKB in the QMGR address space as
  part of a PC-SS call to the QMGR. The 878 abends are occurring
  while trying to STORAGE OBTAIN storage to hold a DXWB control
  block for an XCF MSGEXIT SRB. This only happens after the DXWB
  quick cell pool has been exhausted, so there must have been
  over 300,000 (approximately 94Mb) DXWB allocated in the
  reported case.
  Logrec shows why the only dump taken was for the initial
  5C6-00E7014F abend. The 878 abends when obtaining a DXWB were
  occurring in CSQ5MGX0, which is protected by FRR routine
  CSQ5MFRR. This routine unconditionally issues an SDUMPX, which
  all look to have failed because another dump was in progress.
  The 5C6-00E20015 abends are protected by FRR routines which try
  to schedule a dump by calling CSQWDSD0. Each of the tasks will
  compete to claim the SCOMDUMP work area. The winner will go
  ahead and start collecting storage and eventually issue the
  SDUMPX. The losers append string 'NODMPW' to the VRA data and
  return.
  Logrec shows that abend sequence SEQ=21750 with TCB 0087D788
  from a CICS job was the one which claimed the SCOMDUMP work
  area. The problem is that it subsequently abended 0C4-04 in
  CSQWDSD0 after claiming the work area. This resulted in it
  returning without scheduling a dump. A dispatcher TCB
  subsequently successfully scheduled an SDUMPX for a
  5C6-00E7014F abend from CSQXDMPS.
  The 0C4-04 abend occurred while trying to chain CSQWDSD0's save
  area while running in key 7. The previous save area was a
  304-byte save area provided by z/OS to CSQVIALC's FRR routine
  CSQVAFRR. This is fetch-protected key 0 storage.
  There's no guarantee that the dump from a 5C6-00E20015 abend
  would've collected better doc, but it's not ideal that we
  abended after claiming the SCOMDUMP work area. This problem
  only occurs for abends in storage manager when flag EBSMC has
  been set.
  .
  Additional Keywords:
  ABEND878 ABENDS878
  .
  Additional symptoms:
  The closing test for this APAR says:
    "An 0C4 abend may also occur in CSQWWFST due to incorrectly
     addressing a save area."
  That symptom applies to IBM MQ for z/OS 9.1.0.  The fix is
  present in the 9.2.0 base code. It has been found that a
  storage overlay might occur instead of an ABEND0C4 if the
  invalid address for the save area is addressible.  The first
  word of the overlay points to CSQWDSDM's working storage, and
  that storage likely contains an abend title. There is no
  nearby "CSQWDSDM" eyecatcher.
  .
  Symptoms vary if an overlay occurs.  Symptoms observed include:
  - 5C6-00D70118 ABEND5C6 reason 00D70118 due to the overlay of
  an IPAG control block with the address of CSQWDSDM's dynamic
  storage.
  

Local fix

• N/A
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of IBM MQ for z/OS Version 9       *
  *                 Release 1 Modification 0 and Release 2       *
  *                 Modification 0.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: The QMGR dumping code accesses a save   *
  *                      area using the wrong PSW key. This may  *
  *                      result in an 0C4-04 abend in CSQWDSD0.  *
  *                      This may also result in a dump failing  *
  *                      to be taken.                            *
  ****************************************************************
  Some QMGR recovery routines use the 304 byte save area provided
  on entry to an FRR routine as a save area for a call to
  CSQWDSD0. CSQWDSD0 tries to chain its save area into the
  caller's save area while running in PSW key 7.
  
  An 0C4 abend may also occur in CSQWWFST due to incorrectly
  addressing a save area.
  

Problem conclusion

• The QMGR dumping code has been changed to address the save areas
  correctly and using the correct PSW key.
  

Temporary fix

Comments

• ×**** PE23/12/11 FIX IN ERROR. SEE APAR PH58705  FOR DESCRIPTION
  

APAR Information

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

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

  UI80074 UI80154

Modules/Macros

• CSQ0CACB CSQ0COPN CSQ0DEAD CSQ0DPCS CSQ0DSVC CSQ0ERST CSQ0IPRH
  CSQ0LEPL CSQ3AAES CSQ3AM00 CSQ3AMFR CSQ3AUCM CSQ3AUCN CSQ3AUFR
  CSQ3AUGI CSQ3CT30 CSQ3CT80 CSQ3EXT0 CSQ3GCAB CSQ3ID80 CSQ3IDES
  CSQ3LCHX CSQ3PR00 CSQ3RIA0 CSQ3RIM0 CSQ3RIND CSQ3RRSR CSQ3RRSX
  CSQ3RRXF CSQ3SSES CSQ3SSFR CSQ9SCN9 CSQAPRHX CSQARIB  CSQGEXIT
  CSQGFFRR CSQGFRCV CSQGGEPL CSQIRECP CSQJB004 CSQJC001 CSQJC003
  CSQJC006 CSQJC008 CSQJC09A CSQJCR01 CSQJOFF6 CSQJOFF9 CSQJPOPN
  CSQJR007 CSQJR06A CSQJRE01 CSQJRE08 CSQJRE26 CSQJW008 CSQJW206
  CSQJWE01 CSQMALCH CSQMCALH CSQMCCHT CSQMCDLC CSQMCFEF CSQMCFRQ
  CSQMCFTK CSQMCFWU CSQMCIDT CSQMCLMT CSQMCMHB CSQMCPRH CSQMCRES
  CSQMCTXE CSQMCTXS CSQMFMH1 CSQMXARH CSQMXCLN CSQMZLOO CSQRCAFR
  CSQRCRFR CSQRCRQS CSQRCRSC CSQRCSHT CSQRCURS CSQRIURS CSQRPBCS
  CSQRPBCW CSQRPECS CSQRPLCS CSQRRRQS CSQRRURS CSQRUA01 CSQRUB01
  CSQRUC01 CSQRUE01 CSQSCON  CSQSCON2 CSQSDMPS CSQSFACL CSQSFBK
  CSQSFPL  CSQSGMN  CSQSHDWN CSQSPOWN CSQSPURS CSQSRSUP CSQSTERM
  CSQSVPL  CSQUZAP  CSQV002M CSQVCFRR CSQVCONN CSQVCRTH CSQVCST0
  CSQVDISC CSQVDST0 CSQVEOT1 CSQVEUS1 CSQVEUS2 CSQVEUS3 CSQVEUS4
  CSQVFACE CSQVFEB  CSQVGACE CSQVIALC CSQVLEPL CSQVLFRR CSQVLTT0
  CSQVSDC0 CSQVSLK  CSQVSLT0 CSQVSRRX CSQVSRX  CSQVSUL0 CSQVTFRR
  CSQVTRTH CSQVUTIL CSQVXLT0 CSQVXUL0 CSQWAAPI CSQWACC6 CSQWACCV
  CSQWDSD0 CSQWDSDM CSQWDST2 CSQWVFRR CSQWVOPX CSQWVSMT CSQWVSR2
  CSQWVZSA CSQWVZSS CSQWVZXT CSQWWFST CSQXDTRM CSQXFSTR CSQXGRIM
  CSQXJST  CSQXSUPR CSQXTCNC CSQXTCTL CSQYALLI CSQYASCP CSQYEAT2
  CSQYEATE CSQYEPL0 CSQYESCF CSQYESWE CSQYLGBL CSQYLGUN CSQYMESP
  CSQYMESS CSQYSIRM CSQYSTRT
  

Fix information

• Fixed component name

  IBM MQ Z/OS V9

• Fixed component ID

  5655MQ900

Applicable component levels

• R100 PSY UI80074

     UP22/04/16 P F204 {

• R200 PSY UI80154

     UP22/05/13 P F205 {

Fix is available

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