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NAME | DESCRIPTION | AUTOMATION | SEE ALSO | COLOPHON |
WARNING::DEBUGINFO(7stap) WARNING::DEBUGINFO(7stap)
warning::debuginfo - systemtap missing-debuginfo warnings
For many symbolic probing operations, systemtap needs DWARF debuginfo
for the relevant binaries. This often includes resolving
function/statement probes, or $context variables in related handlers.
DWARF debuginfo is created by the compiler when using CFLAGS -g, and
may be found in the original binaries built during compilation, or
may have been split into separate files. The
SYSTEMTAP_DEBUGINFO_PATH environment variable affects where systemtap
looks for these files.
If your operating system came from a distributor, check with them if
debuginfo packages or variants are available. If your distributor
does not have debuginfo-equipped binaries at all, you may need to
rebuild it.
Systemtap uses the elfutils library to process ELF/DWARF files. The
version of elfutils used by systemtap is the number after the slash
in the -V output:
% stap -V
Systemtap translator/driver (version 2.3/0.156, rpm 2.3-1.fc19)
Copyright (C) 2005-2014 Red Hat, Inc. and others
[...]
This indicates systemtap version 2.3 with elfutils version 0.156.
kernel debuginfo
For scripts that target the kernel, systemtap may search for
the vmlinux file created during its original build. This is
distinct from the boot-loader's compressed/stripped vmlinuz
file, and much larger. If you have a hand-built kernel, make
sure it was built with the CONFIG_DEBUG_INFO=y option. Some
Linux distributions may include several kernel variants, in‐
cluding a confusingly named kernel-debug (an alternative ker‐
nel, with its own kernel-debug-debuginfo package), which is
not the same thing as the kernel-debuginfo (DWARF data for the
base kernel). The stap-prep program can help install the
right set.
process debuginfo
For scripts that target user-space, systemtap may search for
debuginfo. If you have hand-built binaries, use CFLAGS=-g -O2
to compile them.
minidebuginfo
On some systems, binaries may be compiled with a subset of de‐
buginfo useful for function tracing and backtraces. This
'Minidebuginfo' is a xz compressed section labeled .gnu_debug‐
data. Support for minidebuginfo relies on elfutils version
0.156 or later.
compressed debuginfo
On some systems, debuginfo may be available, but compressed
into .zdebug_* sections. Support for compressed debuginfo re‐
lies on elfutils version 0.153 or later.
unnecessary debuginfo
In some cases, a script may be altered to avoid requiring de‐
buginfo. For example, as script that uses probe syscall.*
probes could try instead probe nd_syscall.* (for non-DWARF
syscall): these work similarly, and use more intricate (frag‐
ile) tapset functions to extract system call arguments. An‐
other option is use of compiled-in instrumentation such as
kernel tracepoints or user-space <sys/sdt.h> markers in li‐
braries or executables, which do not require debuginfo. If
debuginfo was required for resolving a complicated
$var->foo->bar expression, it may be possible to use
@cast(var,"foo","foo.h")->foo->bar to synthesize debuginfo for
that type from a header file.
On some platforms, systemtap may advise what commands to run, in
order to download needed debuginfo. Another possibility is to invoke
systemtap with the --download-debuginfo flag. The stap-prep script
included with systemtap may be able to download the appropriate
kernel debuginfo. Another possibility is to install and use a
stap-server remote-compilation instance on a machine on your network,
where debuginfo and compilation resources can be centralized. Try
the stap --use-server option, in case such a server is already
running.
gcc(1),
stap(1),
stappaths(7),
stap-server(8),
stap-prep(1),
strip(1),
warning::symbols(7stap),
error::dwarf(7stap),
error::reporting(7stap),
error::contextvars(7stap),
http://elfutils.org/ ,
http://fedoraproject.org/wiki/Features/MiniDebugInfo
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
WARNING::DEBUGINFO(7stap)
Pages that refer to this page: error::buildid(7stap), error::dwarf(7stap), error::pass2(7stap), warning::symbols(7stap)