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NAME | DESCRIPTION | SEE ALSO | COLOPHON |
ERROR::FAULT(7stap) ERROR::FAULT(7stap)
error::fault - memory access faults
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).
stap(1),
error::reporting(7stap)
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 2017-07-05. If you dis‐
cover 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)