PowerPath for Linux : Unable to start PowerPath on Linux system || Getting error "Address for lookup function is missing"

           

   Article Number:     504371                                   Article Version: 4     Article Type:    Break Fix 
   

 


Product:

 

PowerPath for Linux

 

Issue:

 

 

# systemctl start PowerPath.service   
    PowerPath could not load module emcp   
    Error loading PowerPath kernel modules   
   
    From messages file --   
    systemd[1]: Starting PowerPath startup script...                                                     
    kernel: emcp: module license 'Proprietary' taints kernel.                                            
    kernel: Disabling lock debugging due to kernel taint                                                 
    kernel: emcp: module verification failed: signature and/or required key missing - tainting kernel    
    kernel: emcp: applying kernel_stack fix up                                                           
    systemd-udevd[604]: specified group 'lp' unknown                                                     
    kernel: Warning:emcp:emcp: Address for lookup function is missing                                    
    PowerPath[2869]: Starting PowerPath: PowerPath could not load module emcp                            
    PowerPath[2869]: Error loading PowerPath kernel modules                                              
    PowerPath[2869]: failed                                                                              
    systemd[1]: Stopping PowerPath startup script...     
                                                           

 

 

Cause:

 

 

The Linux system kernel was tuned by    
   
    kernel.randomize_va_space = 2   
    kernel.kptr_restrict = 2   
   
    # cat /proc/sys/kernel/kptr_restrict   
    2   
   
    Above settings/tuning made all the addresses in "/proc/kallsyms" as 0x0000000000 which is not normal and it is not expected by PowerPath startup script. Hence PowerPath service was failing to start.
                                                           

 

 

Change:

 

 

Installed PowerPath on Linux system and tried to start the PowerPath but it failed.                                                           

 

 

Resolution:

 

 

Need to revert back the below parameters to the default value. So that "/proc/ kallsyms" start listing proper addresses. And then try to start PowerPath service. It should start.    
   
    kernel.randomize_va_space =    
    kernel.kptr_restrict =    
   
    # cat /proc/sys/kernel/kptr_restrict   
    1