assigned_user_credentials = pr_stapdev

[Henrik /KaarPoSoft <henrik at kaarposoft dot dk>]

Dear all,

Systemtap version 2.1.

I have created a small systemtap script and compiled with "stap 
--privilege=stapsys".
As root, I can "staprun" the script just fine.

As root I have installed the script in "/lib/modules/`uname -r`/systemtap".

If I try "staprun" as a user in groups staprun and stapsys (but NOT 
stapdev), I get this error message:
ERROR: Your privilege credentials (stapdev) are insufficient to run this 
module (stapsys required).

I find this a bit strange, as the user is NOT a member of stapdev as 
claimed, but the user IS a member of stapsys as required.

The above scenario was working way back with systemtap version 1.8, but 
is now failing with 2.1.

I looked at commit 429a4963, which introduced this around line 756 in 
staprun/staprun_funcs.c:
  if (assigned_user_credentials)
    assigned_user_credentials = pr_stapdev;

If I change this to
    assigned_user_credentials |= pr_stapdev;
the above scenario works like a charm.

As I have very limited knowledge of systemtap, I would appreciate your 
comments on this workaround.

Am I doing something wrong, and should use a different combination of 
privileges and groups?
Or is there really a problem with systemtap?
And if there IS a problem, is the above workaround the correct solution?

Any help on this would be most appreciated...

/Henrik