systemtap: a linux trace/probe tool
Visit the project web site at <http://sourceware.org/systemtap>,
for documentation and mailing lists for developers and users.
This is free software.
See the COPYING file for redistribution/modification terms.
See the INSTALL file for generic build instructions.
See the HACKING file for contribution advice.
Prerequisites:
- linux kernel
- kernel module build environment (kernel-devel rpm) and/or dyninst
- optionally, debugging information for kernel/user-space being instrumented
- C compiler (same as what kernel was compiled with)
- elfutils with libdwfl for debugging information parsing
- root privileges
Installation steps:
- Install any debuginfo packages you need, for kernel and/or userspace.
On modern Fedora, # debuginfo-install kernel [...]
(Beware of confusion between kernel vs. kernel-debug vs kernel-PAE etc.
variants. Each likely has a corresponding development and debuginfo
package.)
- Install the systemtap package.
On modern Fedora, # yum install systemtap systemtap-runtime
Build steps:
- Consider installing the kernel-debuginfo, kernel-devel, gcc and
dependent packages (or see below if you are building your own
kernels from source). If using only the pure-userspace dyninst
backend, install gcc and dyninst-devel.
- If available, install your distribution's copy of elfutils and its
development headers/libraries.
Or if desired, download an elfutils source release to build in
"bundled mode" (below), and untar it into some new directory.
Or if desired, build elfutils separately one time, and install
it to /usr/local.
See http://fedorahosted.org/elfutils/
Version 0.151 is recommended for i386 hosts probing prelinked programs.
(PR12141)
- On modern Fedora, install general optional build-requisites:
# yum-builddep systemtap
On modern Debian/Ubuntu, similarly:
# apt-get build-dep systemtap
- Download systemtap sources:
http://sourceware.org/systemtap/ftp/releases/
http://sourceware.org/systemtap/ftp/snapshots/
(or)
git clone git://sourceware.org/git/systemtap.git
(or) http://sourceware.org/git/systemtap.git
- Build systemtap normally:
% .../configure [other autoconf options]
Or, with build it with a bundled internal copy of elfutils:
% .../configure --with-elfutils=ELFUTILS-SOURCE-DIR [other autoconf options]
(Note that elfutils > 0.139 requires gcc > 4.0 or else the
appropriate elfutils-portability.patch. Ensure decompression
library headers/libraries are installed for elfutils' use.)
Consider configuring with "--enable-dejazilla" to automatically
contribute to our public test result database.
Consider configuring with "--prefix=DIRECTORY" to specify an
installation directory other than /usr/local. It can be an ordinary
personal directory.
% make all
# make install
To uninstall systemtap:
# make uninstall
- Run systemtap:
To run systemtap after installation, add $prefix/bin to your $PATH, or
refer to $prefix/bin/stap directly. If you keep your build tree
around, you can also use the "stap" binary there.
Some samples should be available under $prefix/share/doc/systemtap/examples.
For the normal linux-kernel-module based backend, run "stap" as
root. If desired, create "stapdev" and "stapusr" entries in
/etc/groups. Any users in "stapdev"+"stapusr" will be able to run
systemtap as if with root privileges. Users in "stapusr" only may
launch (with "staprun") pre-compiled probe modules (created by "stap
-p4 ...") that a system administrator copied under
/lib/modules/`uname -r`/systemtap. "stapusr" may also be permitted
to create arbitrary unprivileged systemtap scripts of their own.
See README.unprivileged for additional setup instructions.
To run a simple test.
# stap -v -e 'probe vfs.read {printf("read performed
"); exit()}'
To run the full test suite from the build tree.
# make installcheck
For the prototype dyninst pure-userspace backend, run "stap" as any user.
% stap --runtime=dyninst -e 'probe process.function("*") {
println(pn(), ":", $$parms) }' -c 'ls'
Tips:
- By default, systemtap looks for the debug info in these locations:
/boot/vmlinux-`uname -r`
/usr/lib/debug/lib/modules/`uname -r`/vmlinux
/lib/modules/`uname -r`/vmlinux
/lib/modules/`uname -r`/build/vmlinux
Building a kernel.org kernel:
- Consider applying the utrace kernel patches, if you wish to probe
user-space applications. http://sourceware.org/systemtap/wiki/utrace
Or if your kernel is near 3.5, apply the uprobes and related patches
(see NEWS). Or if your kernel is >= 3.5, enjoy the built-in uprobes.
- Build the kernel using your normal procedures. Enable
CONFIG_DEBUG_INFO, CONFIG_KPROBES, CONFIG_RELAY, CONFIG_DEBUG_FS,
CONFIG_MODULES, CONFIG_MODULE_UNLOAD, CONFIG_UTRACE if able
- % make modules_install install headers_install
- Boot into the kernel.
- If you wish to leave the kernel build tree in place, simply run
% stap -r /path/to/kernel/build/tree [...]
You're done.
- Or else, if you wish to install the kernel build/debuginfo data into
a place where systemtap will find it without the "-r" option:
% ln -s /path/to/kernel/build/tree /lib/modules/RELEASE/build
- Instead of using the "-r" option, you can also use the environment
variable SYSTEMTAP_RELEASE to direct systemtap to the kernel data.