Cannot access local variables using systemtap

Cannot access local variables using systemtap



I am just getting started using systemtap. On my 64bit Ubuntu 13.04

system, I installed systemtap and dependencies + systemtap-doc and

elfutils then added the ddep repository to my apt/sources.list and

installed the dbgsym package for my kernel (3.8.0-29.42).

I then tried running the examples in

/usr/share/doc/systemtap-doc/examples/general (e.g., key.stp), but I got

semantic error: not accessible at this address [man error::dwarf] ...

identifier '$event_type' at key.stp:8:7

I then ran the "Work around broken dbgsym file layount..."-script as

described at wiki.ubuntu.com/Kernel/Systemtap

Still the same error and similar errors occur running the other scripts

whenever a local variable is accessed.

So I wrote a little script following section "Determine local variables at

probe point" on the same page to give me a list of local variables in

kbd_event.

probe begin {

printf ("probe installed")

}

probe kernel.function("kbd_event") {

printf ("%s locals [%s]\n", probefunc(), $$locals)

exit()

}

which gives me

probe installed

kbd_event locals []

So it looks like stap doesn't see any local variables and this is where I

am stuck.

Any ideas what I am missing or what I could try next?

Thanks!