Shutdown immediate gives ora-03113

On 11.2.0.2 / IBM AIX on POWER Systems (64-bit)
When run shutdown immediate , got error ORA-03113

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORA-03113: end-of-file on communication channel

The trace files shows the following stacks:
skgdbgcra <- sksdbgcra <- ksdbgcra <- ssexhd <- strncpy
       <- dbkrlSetArbDefaults <- dbkrlWriteAlertText <- dbkrlPril <- ksdfmw <- ksdwra
        <- ssexhd <- strncpy <- dbkrlSetArbDefaults <- dbkrlWriteAlertText <- dbkrlPril
         <- ksdfmw <- ksdwra <- ssexhd <- strncpy <- dbkrlSetArbDefaults
          <- dbkrlWriteAlertText <- dbkrlPril <- ksdfmw <- ksdwra <- ssexhd
           <- strncpy <- dbkrlSetArbDefaults <- dbkrlWriteAlertText <- dbkrlPril <- ksdfmw
            <- ksdwra <- ssexhd <- strncpy <- dbkrlSetArbDefaults <- dbkrlWriteAlertText