Re: semantic error: libdwfl failure (dwfl_linux_kernel_report_modules): Exec format error

[fche@redhat.com (Frank Ch. Eigler)]

Esther Horbert <horbert@lfbs.RWTH-Aachen.DE> writes:

> [...]
> We installed like described here:
> http://sourceware.org/systemtap/wiki/SystemtapOnDebian only installed
> the kernel manually (make install).
> Does somebody know what this Exec format error means and how to fix it?
> [...]

> # stap -vvv -e 'probe kernel.function("sys_open") {log("hello world")
> exit()}'

I note there is no systemtap version identification printed here.
This means that your copy of systemtap is pretty old.

> [...]
> semantic error: libdwfl failure (dwfl_linux_kernel_report_modules):
> Exec format error
> Ensure kernel debuginfo is installed
> [...]

More modern versions give a more precise error message.

Your elfutils is also rather aged.  If you rebuild with a newer
systemtap (perhaps a cvs snapshot), consider also fetching a copy
of elfutils from http://sources.redhat.com/systemtap/ftp/elfutils
and using the "--with-elfutils=" bundling method.

>[...]
> # ls -l /boot/vmlinux-$(uname -r)
> -rwxr-xr-x 1 root root 43252479 2008-01-30 16:21 /boot/vmlinux-2.6.20-oprofile

That looks big enough to have all the dwarf data we could possibly want,
so you should not have to rebuild that nor reboot (if you're already running it).

- FChE