VM66350: SUMMARY UNIT CHECK PROCESSING RECOVERY STALLS

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• SUC processing can possibly cause a DASD device to stall.  If,
  during SUC recovery other errors are encountered, such as reset
  notification a device may have a Suspend Multipath Reconnect
  command added to the CCW string.  This could cause the I/O to be
  queued instead of driven on the device.  This would cause the
  device to stall since the SUC recovery processing isn't allowed
  to continue.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All z/VM users                               *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
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  * RECOMMENDATION: APPLY PTF                                    *
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  Summary unit check recovery processing can possibly stall due
  to a Suspend Multipath Reconnect (SMR) CCW being issued
  prior to the Reset Summary Unit Check CCW.
  An SMR CCW does not work through a summary unit check condition
  and will get queued instead of executed stalling recovery
  of the Summary Unit Check condition indefinitely.
  

Problem conclusion

• Summary Unit Check (SUC) recovery does not require an SMR CCW.
  Therefore, it will be removed so that this possible stall will
  be eliminated.
  

Temporary fix

• *********
  * HIPER *
  *********
  FOR RELEASE VM/ESA CP/ESA R640 :
  PREREQ: NONE
  CO-REQ: NONE
  IF-REQ: NONE
  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:

  UM35592 UM35593

Modules/Macros

• HCPDTE
  

Fix information

• Fixed component name

  VM CP

• Fixed component ID

  568411202

Applicable component levels

• R640 PSY UM35592

     UP20/02/12 P 2001 ¢

• R710 PSY UM35593

     UP20/02/12 P 2101 ¢

Fix is available

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