IJ53006: KERNEL CRASH WHILE RUNNING OUTBOUND PREFETCH.

APAR status

• Closed as program error.

Error description

• Kernel null pointer exception while running outbound metadata
  prefetch.
  

Local fix

Problem summary

• Deadlock hang condition in which InodeRevokeWorkerThread threads
  will hang, and dumping waiters (e.g. via "mmdiag --waiters")
  will show: InodeRevokeWorkerThread: for flush mapped pages, VMM
  iowait
  

Problem conclusion

• This problem is fixed in 5.1.9.7
  To see all Spectrum Scale APARs and their respective
  Fix solutions refer to page: 
  https://public.dhe.ibm.com/storage/spectrumscale/spectrum_scale
  _apars.html
  
  Benefits of the solution:
  Avoid deadlock by changing PrepareForMnodeRelinquish() to flush
  mmapped pages before discarding cached indirect blocks.
  
  Work Around:
  avoiding the use of mmap or file replication will avoid the
  problem
  
  Problem trigger:
  Use of mmap when there are replicas that have missed updates.
  
  Symptom:
  Hang/deadlock
  
  Platforms affected:
  Linux Only
  
  Functional Area affected:
  GPFS Core (mmap)
  
  Customer Impact:
  High Importance
  

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:

Fix information

• Fixed component name

  SPEC SCALE STD

• Fixed component ID

  5737F33AP

Applicable component levels