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

# [NAME](#NAME)

warning::debuginfo - systemtap missing-debuginfo warnings

# [DESCRIPTION](#DESCRIPTION)

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](#kernel)

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](#process)

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](#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](#compressed)

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](#unnecessary)

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](#OTHER_AUTOMATION)

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](#SEE_ALSO)

```
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
```

---

Document: warning::debuginfo(7stap) from systemtap 5.6-r0 (Chainguard OS)
Source: https://sourceware.org/git/systemtap.git