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HTML rendering created 2023-12-22 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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NAME | DESCRIPTION | SEE ALSO | COLOPHON |
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WARNING::BUILDID(7stap) WARNING::BUILDID(7stap)
warning::buildid - build-id verification failures
Because systemtap's script translation / execution stages may be
executed at different times and places, it is sometimes necessary
to verify certain invariants. One such invariant is that if a
script was informed by translate-time analysis of executables,
then those same executables need to be used at run time. This
checking is done based upon the build-id, a binary hash that
modern (post-2007) compilers/toolchains add as an NT_GNU_BUILD_ID
ELF note to object files and executables. Use the readelf -n
command to examine the build-ids of binaries, if you are
interested.
Only scripts are sensitive to executables' build-ids: generally
those that perform deep analysis of the binaries or their
debuginfo. For example, scripts that place .function or
.statement probes, or use stack backtrace-related tapset
functions may be sensitive. Other scripts that rely only on
process.mark or kernel.trace probes do not require debuginfo.
See the DWARF DEBUGINFO section in the stapprobes(3stap) man
page.
During translation, systemtap saves a copy of the relevant files'
build-ids within the compiled modules. At run-time, the modules
compare the saved ones to the actual run-time build-ids in
memory. The warning message indicates that they did not match,
so the module will decline placing a probe that was computed
based upon obsolete data. This is important for safety, as
placing them at an inappropriate address could crash the
programs. However, this is not necessarily a fatal error, since
probes unrelated to the mismatching binaries may operate.
A build-id mismatch could be caused by a few different
situations. The main one is where the executable versions or
architecture were different between the systemtap translation and
execution times/places. For example, one may run a stap-server
on a slightly different version of the OS distribution. Someone
may have rebuilt a new kernel image, but preserved the previous
version numbers. The kernel running on the workstation may be
slightly different from the version being targeted - perhaps due
to a pending kernel upgrade leaving different files on disk
versus running in memory. If your OS distribution uses separate
debuginfo packages, the split .debug files may not exactly match
the main binaries.
To disable build-id verification warnings, if one is confident
that they are an artefact of build accidents rather than a real
mismatch, one might try the -DSTP_NO_BUILDID_CHECK option.
http://fedoraproject.org/wiki/Releases/FeatureBuildId ,
stap(1),
stapprobes(3stap),
warning::debuginfo(7stap),
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 2023-12-22. (At that
time, the date of the most recent commit that was found in the
repository was 2023-12-21.) 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
WARNING::BUILDID(7stap)
Pages that refer to this page: error::dwarf(7stap)
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HTML rendering created 2023-12-22 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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