IJ47843: KERNEL CRASH WITH ASSERT: NPREFETCHEDBUFFERS > 0

APAR status

• Closed as program error.

Error description

• Kernel crash with assert: nPrefetchedBuffers > 0. This could
  happen when application using multiple threads to perform
  sequential read or write more than 65535 blocks on the same open
  file. The starting offset of the read/write must not be on GPFS
  block boundary.
  

Local fix

• Close/reopen file before performing more than 65535 sequential
  read/write on the same file using multiple threads.
  

Problem summary

• Kernel crash with assert: nPrefetchedBuffers > 0. This could
  happen when application using multiple threads to perform
  sequential read or write more than 65535 blocks on the same open
  file. The starting offset of the read/write must not be on GPFS
  block boundary.
  

Problem conclusion

• This problem is fixed in 5.1.2.13
  
  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:
  
  Prevent the unexpected kernel crash that could occur when
  multiple threads are used to perform sequential read/write on
  the same open file.
  
  Work Around:
  
  Close/reopen file before performing more than 65535 sequential
  read/write on the same file using multiple threads.
  
  Problem trigger:
  
  Performing sequential read/write on the same file using multiple
  threads where starting offsets of each read/write is not on GPFS
  block boundary.
  
  Symptom:
  
  Abend/Crash
  
  Platforms affected:
  
  ALL Operating System environments
  
  Functional Area affected:
  
  All Scale Users
  
  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