warning::debuginfo(7stap) — Linux manual page

NAME | DESCRIPTION | OTHER AUTOMATION | SEE ALSO | COLOPHON

WARNING::DEBUGINFO(7stap)                      WARNING::DEBUGINFO(7stap)

NAME         top

       warning::debuginfo - systemtap missing-debuginfo warnings

DESCRIPTION         top

       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 4.2/0.178, rpm 4.2-1.fc30)
              Copyright (C) 2005-2019 Red Hat, Inc. and others
              [...]

       This indicates systemtap version 4.2 with elfutils version 0.178.

       New enough versions of elfutils (0.178+) enable systemtap to
       automatically download correct debuginfo from servers run by you,
       your organization, and/or someone on the public internet.  Try:

              % export DEBUGINFOD_URLS=https://debuginfod.elfutils.org/
              % export DEBUGINFOD_PROGRESS=1   # for progress messages, if you like

       and rerun systemtap.  It might just work.  If it doesn't, read
       on.

       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, including a confusingly
              named kernel-debug (an alternative kernel, 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
              debuginfo useful for function tracing and backtraces.
              This 'Minidebuginfo' is a xz compressed section labeled
              .gnu_debugdata.  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 relies on elfutils version 0.153 or
              later.

       unnecessary debuginfo
              In some cases, a script may be altered to avoid requiring
              debuginfo.  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 (fragile) tapset functions to extract
              system call arguments.  Another option is use of compiled-
              in instrumentation such as kernel tracepoints or user-
              space <sys/sdt.h> markers in libraries 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.

OTHER AUTOMATION         top

       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, which uses
       ABRT.  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.

SEE ALSO         top

       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),
       debuginfod(8),
       http://elfutils.org/ ,
       https://sourceware.org/elfutils/Debuginfod.html ,
       http://fedoraproject.org/wiki/Features/MiniDebugInfo 

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 2021-04-01.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2021-03-29.)  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::DEBUGINFO(7stap)

Pages that refer to this page: error::dwarf(7stap)error::pass2(7stap)warning::buildid(7stap)warning::symbols(7stap)