PowerPath for AIX 6.4: powerdd: MpxPeriodicCallbackDaemon race condition crash


   Article Number:     537201                                   Article Version: 3     Article Type:    Break Fix 




PowerPath for AIX 6.4





Dell EMC SW: PowerPath for AIX 6.4   
        CPU 16 CSA F00000002FF47600 at time of crash, error code for LEDs: 30000000       
        pvthread+010300 STACK:       
        [F1000000C07A8608]powerdd:PowerEnqueue+000028 (F1000000C04DFEF0, 0000000000000000)       
        [F1000000C07AAC0C]powerdd:PowerGetSemaNew+00020C (F1000000C04DFE90, 0000000100000001)       
        [F1000000C07AAD78]powerdd:PowerGetSema+000018 (F1000000C04DFE90)       
        [F1000000C04D249C]mpxext:MpxGetHostInfo+00009C (F1000000C04DFF60, F1000000C04DC940)       
        [F1000000C049815C]mpxext:MpxDeviceMountStatsRpt+00005C (F1000A03F0900800, 15C06FB653F3BC50)       
        [F1000000C049AA6C]mpxext:MpxPeriodicCallout+001EEC (F1000A03F01C2100)       
        [F1000000C07AD4CC]powerdd:PowerServiceDaemonQ+00010C (F1000A03F06D3E00)       
        [F1000000C07CDCD4]powerdd:PowerServiceDaemonQWrap+000074 (0000000000000000, 0FFFFFFFF3FFFFF0,       
        [00014D70].hkey_legacy_gate+00004C ()       
        [0029B310]procentry+000010 (??, ??, ??, ??)       
        [kdb_real_mem] no real storage @ FFFFFFFFFFF5D50       
        (16)> th       
                       SLOT NAME    STATE   TID PRI  RQ CPUID CL WCHAN       
        pvthread+010300 259*MpxPerio RUN  103006B 03C  16        0       
        NAME................ MpxPeriodicCallbackDaemon       
        FLAGS............... KTHREAD       
        (16)> vmlog       
        Most recent VMM errorlog entry       
        Error id              = DSI_PROC       
        Exception DSISR/ISISR = 000000000A000000       
        Exception srval       = 00007FFFFFFFD080       
        Exception virt addr   = 0000000000000008       
        Exception value       = 00000086 EXCEPT_PROT       






PowerPath for AIX 6.4 bug   

      A race condition due to a NULL de-reference in the thread involving multiple function calls from PowerPath 6.4 code.   







    Disable the "device in use to array report" feature.   
    Fixed in PowerPath for AIX 7.0 which is currently available for download at the support site.






The following command can be used to disable the device in use to array report feature:   
    powermt set dev_inuse_to_array_report=off class=symm   
    The following command can be used to confirm that the device in use to array report feature is disabled:   
    # powermt display options       
                Show CLARiiON LUN names:      true       
                Path Latency Monitor: Off       
                Performance Monitor: disabled       
                Autostandby:  IOs per Failure (iopf): enabled       
                              iopf aging period     : 1 d       
                              iopf limit            : 6000       
                System Class  Attributes       
                ------------  ----------       
                Symmetrix     periodic autorestore = on       
                              reactive autorestore = on       
                              status = managed       
                              proximity based autostandby = off       
                              auto host registration = enabled       
                              autopath mask counter = enabled       
                              autopath array controlled counter = enabled       
                              device to array performance report = enabled       
                              device in use to array report = disabled
    This bug is specific to PowerPath for AIX 6.4.   
    This is an isolated corner case, the chance of hitting the issue is remote.    
    Note: If you are running any microcode version below 5978.221.221 then there won't be any functionality impact.    
    If you running microcode 5978.221.221 above this version then turning this parameter off, a storage admin will    
    not know if the device is in use or not from the SYMM array perspective.