error::fault(7stap) — Linux manual page

NAME | DESCRIPTION | SEE ALSO | COLOPHON

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

NAME         top

       error::fault - memory access faults

DESCRIPTION         top

       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         top

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

COLOPHON         top

       This page is part of the systemtap (a tracing and live-system
       analysis tool) project.  Information about the project can be
       found at ⟨https://sourceware.org/systemtap/⟩.  If you have a bug
       report for this manual page, send it to systemtap@sourceware.org.
       This page was obtained from the project's upstream Git repository
       ⟨git://sourceware.org/git/systemtap.git⟩ on 2021-06-20.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2021-06-18.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

                                                     ERROR::FAULT(7stap)

Pages that refer to this page: stapprobes(3stap)error::pass5(7stap)