NAME

       error::fault - memory access faults

DESCRIPTION

       Read  or  write  faults  can  occur  during  the  operation  of  a systemtap script, if the script causes
       dereferencing of a pointer that turns out to be invalid.  This can be caused by using  context  variables
       that  do  not  happen  to  have valid values, or perhaps references to memory that is unavailable at that
       moment due to paging.

       These fault conditions are benign because they  are  caught  by  the  systemtap  runtime,  which  cleanly
       terminates  the  script.   If  quick  termination  is  not  desired, consider using the --skip-badvars or
       --suppress-handler-errors or -DMAXERRORS=NN stap  options,  or  wrapping  relevant  parts  of  the  probe
       handlers in a try/catch block.

       It may be possible to adjust the target program, to make it more likely that needed context variables are
       paged  in  when  systemtap  looks  for  them.   Consider  adding  some  lightweight processing on the key
       variables, like a strlen(foo) for a string, or iterating across elements of an array or linked  list,  or
       touching  a  few  bytes  of a heap-allocated block.  The idea is to trigger any page faults in the target
       program, before systemtap would need to (but can't).

SEE ALSO

       stap(1),
       error::reporting(7stap)

                                                                                             ERROR::FAULT(7stap)