ERROR::FAULT(7stap)                                        ERROR::FAULT(7stap)

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)