IJ21071: NMI WATCHDOG: BUG: SOFT LOCKUP - CPU STUCK [NFSD]

APAR status

• Closed as program error.

Error description

• On RHEL 7 nodes (pre-Linux kernel v3.18), in the GPFS kernel NFS
  support
  
  environment, GPFS may try to acquire some mutex, while holding
  an inode
  
  spin lock, which may be detected as a soft lockup issue by the
  kernel NMI watchdog.
  

Local fix

Problem summary

• On RHEL 7 nodes (pre-Linux kernel v3.18), in the GPFS kernel NFS
   support
  
  environment, GPFS may try to acquire some mutex, while holding
  an inode
  
  spin lock, which may be detected as a soft lockup issue by the
  kernel NMI watchdog.
  

Problem conclusion

• Benefits of the solution, in customer terms:
  
  Avoid CPU stuck and performance impacts
  
  Work around:
  
  None
  
  Problem trigger:
  
  GPFS breaks some spin lock holding policy in NFS support
  environment
  
  Symptom:
  
  Performance Impact/CPU stuck
  
  Platforms affected:
  
  All RHEL 7.x
  
  Functional Area affected:
  
  All users of KNFS/CNFS
  
  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

  GPFS NR POWER E

• Fixed component ID

  5725Q01NP

Applicable component levels