IJ50654: MMSHUTDOWN CAUSED KERNEL CRASH

APAR status

• Closed as program error.

Error description

• ABSTRACT:
  mmshutdown caused kernel crash
  
  Error Description:
  mmshutdown caused kernel crash while calling
  dentry_unlink_inode with
  the backtrace like this:
  
  ...
  #10  page_fault at ffffffff8d8012e4
  #11  iput at ffffffff8cef25cc
  #12  dentry_unlink_inode at ffffffff8ceed5d6
  #13  __dentry_kill at ffffffff8ceedb6f
  #14  dput at ffffffff8ceee480
  #15  __fput at ffffffff8ced3bcd
  #16  ____fput at ffffffff8ced3d7e
  #17  task_work_run at ffffffff8ccbf41f
  #18  do_exit at ffffffff8cc9f69e
  ...
  
  Reported in:
  Spectrum Scale 5.1.7.1
  
  Known Impact:
  Kernel crash
  
  Verification steps:
  N/A
  
  Recovery action:
  N/A
  
  Local Fix:
  N/A
  

Local fix

Problem summary

• mmshutdown caused kernel crash while calling dentry_unlink_inode
  with the backtrace like this:
  ...
  #10  page_fault at ffffffff8d8012e4
  #11  iput at ffffffff8cef25cc
  #12  dentry_unlink_inode at ffffffff8ceed5d6
  #13  __dentry_kill at ffffffff8ceedb6f
  #14  dput at ffffffff8ceee480
  #15  __fput at ffffffff8ced3bcd
  #16  ____fput at ffffffff8ced3d7e
  #17  task_work_run at ffffffff8ccbf41f
  #18  do_exit at ffffffff8cc9f69e
  ...
  

Problem conclusion

• This problem is fixed in 5.2.0.1
  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 rare occurrences that kernel crashes during mmshutdown
  
  Work Around:
  None
  
  Problem trigger:
  Kernel crash with dentry_unlink_inode when run mmshutdown.For
  the normal open(), the kernel seems to call fops_get, which is a
  call totry_module_get.The fix: We need to call try_module_get
  when we install cleanupFD.This will hold the module in place
  until gpfs_f_cleanup (called when the lastmmfsd process
  terminates and allows basic cleanup for next daemon startup)has
  been called for the cleanupFD.
  
  Symptom:
  Kernel crash during mmshutdown
  
  Platforms affected:
  All Linux OS environments
  
  Functional Area affected:
  All Scale Users (Linux)
  
  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