Semantic error on probe module("foo").function("bar")

Semantic error on probe module("foo").function("bar")

[Christian Pössinger]

Hello *,

I'm quiet new to systemtap and trying to understand how everything works
out. I want to connect a probe to a kernel module (mplex-stap) and access
a function within that module.

probe module("mplex-stap").function("mplex_fop_ioctl").return {...}

When I compile the module and load it (either as a out of tree module, or
throuth CONFIG_SAMPLES with the kernel build system) the module loads just
fine, but calling STAP always results in:

semantic error: missing i386 kernel/module debuginfo under
'/lib/modules/2.6.32.9-lttng-0.198/build' while resolving probe point
module("mplex-stap").function("mplex_fop_ioctl").return

Working with probes that tap into syscall.* work like a charm. Am I
missing something in my build system for my own module?

Best Regards,
Christian

Re: Semantic error on probe module("foo").function("bar")

[Christian Pössinger]

After a small discussion on IRC I found the cause of my problem.

My module registers as a character device driver with the name
"mplex-stap". But the module will be displayed as "mplex_stap" on lsmod.
After changing my proble line from:

  probe module("mplex-stap").function("mplex_fop_ioctl").return {...}

to

  probe module("mplex_stap").function("mplex_fop_ioctl").return {...}

everything worked out.


Best Regards,
Christian

On So, 12.09.2010, 14:56, Christian Pössinger sagte:
> Hello *,
>
> I'm quiet new to systemtap and trying to understand how everything works
> out. I want to connect a probe to a kernel module (mplex-stap) and access
> a function within that module.
>
> probe module("mplex-stap").function("mplex_fop_ioctl").return {...}
>
> When I compile the module and load it (either as a out of tree module, or
> throuth CONFIG_SAMPLES with the kernel build system) the module loads just
> fine, but calling STAP always results in:
>
> semantic error: missing i386 kernel/module debuginfo under
> '/lib/modules/2.6.32.9-lttng-0.198/build' while resolving probe point
> module("mplex-stap").function("mplex_fop_ioctl").return
>
> Working with probes that tap into syscall.* work like a charm. Am I
> missing something in my build system for my own module?
>
> Best Regards,
> Christian