OA67480: ABEND978 WITH RSN04 (S978-04) IN IOSVDSTF, FOLLOWED BY THE SVC DUMP

APAR status

• Closed as unreproducible in next release.

Error description

• IOS requested an SVC dump for the VSM S978-04 ABEND in the
  IOSVDSTF module after the attempt to FREEMAIN storage with the
  address not on the double-word boundary.
  FREEMAIN was issued at the very completion of the successful I/O
  request, submitted by the already gone address space against the
  offline device - thus, no impact for the system and its normal
  operations.
  
  ANALYSIS:
  The system trace, generated for the ASID, current in the SVC
  dump (ASID 0001 in the investigated instance), contains four
  subsequent entries:
    I/O 07707 - Completion of the I/O, submitted by IOSVDSTF
    SRB       - POST I/O Processing in the submitting address
  space
    SSRV  78  - FREEMAIN, issued by IOSVDSTF
    *SVCE  D  - ABEND978-04
  
  Device 7707 (in SS0) must be the offline device - thus the
  special treatment by IOS.
  The SSRV 78 (FREEMAIN) entry looks as follows:
    SSRV 78 810C4BF2  0000F803 00000020 02000194
  where
   810C4BF2 is the post-FREEMAIN address in IOSVDSTF
   02000194 is the address of storage to FREEMAIN.
  VSM issues ABEND978 with RSN04 because X'02000194' is not
  aligned to the double-word boundary
  
  This part of storage is not aligned, because the size of the
  preceding part of storage, the DSTF work area, does not provide
  for the necessary alignment.
  
  KNOWN IMPACT:
  There is no impact to the system and active processes in it
  because the ABEND happens at the very end of the successful
  processing of the I/O request in the SRB for the already gone
  address space
  
  VERIFICATION STEPS:
  This may happen only if:
  - the device is OFFLINE
  - the address space, interested in the device, has gone by the
  time of the completion of the I/O request, submitted by it
  
  For the rest, please see the Analysis above
  
  ADDITIONAL SYMPTOMS:
  no additional symptoms, just the already taken SVC dump
  

Local fix

• BYPASS/CIRCUMVENTION:
  not avoidable under the circumstance (the gone address space who
  submitted an I/O request against the offline device)
  
  RECOVERY ACTION:
  there is nothing to recover
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: Users at HBB77D0 and above                   *
  ****************************************************************
  * PROBLEM DESCRIPTION: VSM issues ABEND978-04 in IOSVDSTF      *
  *                      when attempting to FREEMAIN storage     *
  *                      that isn't on a double-word boundary    *
  ****************************************************************
  When IOSVDSTF is tasked by FINDDASD to read the volume label
  from an OFFLINE device, and the address space that is
  interested in the device has gone by the time of the completion
  of the I/O request submitted by it - IOS requests an SVC dump
  for VSM S978-04 ABEND in the IOSVDSTF module after the attempt
  to FREEMAIN storage with the address not on the double-word
  boundary.
  

Problem conclusion

Temporary fix

Comments

•     This APAR is being closed UR1 with the awareness
      of the submitting customer.  This means that a fix to
      this APAR is expected to be delivered from IBM in a
      release (if any) to be available within the next
      36 months.
      Available in 3.2
  

APAR Information

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

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

Fix information

• Fixed component name

  IOS

• Fixed component ID

  5752SC1C3

Applicable component levels