systemtap does not work out of the box on natty

[Balachandran Sivakumar]

when systemtap is installed using apt-get, it installs the necessary packages and once the installation is done, if we run a test sample script, it fails with some errors. This is because the linux-deb-2.6 package doesn't get installed. The ubuntu archives do not seem to have the package and there is a related bug 106957 which talks about a similar issue in Gutsy. The problem here is that even after installing the kernel headers and symlinking from /boot/.... to /lib/modules, it doesn't seem work. The error that I get is:

ganapathy@ganapathy-laptop:/usr/src$ stap -v -e 'probe vfs.read {printf("read performed\n"); exit()}'
Pass 1: parsed user script and 144 library script(s) using 29332virt/22896res/1884shr kb, in 330usr/0sys/324real ms.
semantic error: missing i386 kernel/module debuginfo under '/lib/modules/2.6.38-10-generic/build' while resolving probe point kernel.function("vfs_read")
semantic error: no match while resolving probe point vfs.read
Pass 2: analyzed script: 0 probe(s), 0 function(s), 0 embed(s), 0 global(s) using 29648virt/23580res/2132shr kb, in 40usr/110sys/164real ms.
Pass 2: analysis failed. Try again with another '--vp 01' option.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: systemtap 1.3-2ubuntu2
ProcVersionSignature: Ubuntu 2.6.38-10.46-generic 2.6.38.7
Uname: Linux 2.6.38-10-generic i686
Architecture: i386
Date: Wed Aug 10 23:25:34 2011
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release i386 (20110427.1)
ProcEnviron:
 LANGUAGE=en_IN:en
 LANG=en_IN
 LC_MESSAGES=en_IN.UTF-8
 SHELL=/bin/bash
SourcePackage: systemtap
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Timo Juhani Lindfors (timo-lindfors)]

README.Debian describes how you can install the debug symbols. I don't know how this could be automated. You can have more than one kernel installed and only want debug symbols for one kernel.

If the documentation does not help you, consider running

http://lindi.iki.fi/lindi/systemtap/diagnose-error-cases.bash

and reporting its full output here.

[Michael Terry (mterry)]

Installing the necessary packages is a documented extra step, and natty is EOL. So I'm marking invalid.

[Timo Juhani Lindfors (timo-lindfors)]

Michael, thanks for triaging systemtap bugs. I'd really appreciate if somebody could triage these Ubuntu specific usability issues which I don't hit since I mostly use Debian. (See also https://bugs.launchpad.net/ubuntu/+source/systemtap/+bug/1144040 )

Regarding this particular bug, systemtap 2.1-1~experimental1 added a patch where any failure of 'stap' will point the user directly to README.Debian:

$ stap -v -e 'FOO'
parse error: expected 'probe', 'global', 'function', or '%{'
 saw: identifier 'FOO' at <input>:1:1
     source: FOO
             ^
1 parse error.
Pass 1: parsed user script and 91 library script(s) using 92232virt/25348res/2608shr/23300data kb, in 100usr/20sys/120real ms.
Pass 1: parse failed. [man error::pass1]
Tip: /usr/share/doc/systemtap/README.Debian should help you get started.

Do you think this is prominent enough for users to notice?