Re: Unresolved probes

[David Smith <dsmith at redhat dot com>]

On 03/09/2010 07:11 AM, Steve Dickson wrote:
> Hello,
> 
> I'm working the testsuite/buildok/nfs* and testsuite/buildok/rpc*
> scripts and I'm running across a somewhat familiar problem where
> certain routines are not resolvable.
> 
> Using a "normal" 2.6.34 kernel I get the following errors:
> 
> $ sudo ./run-stap -wp4 testsuite/buildok/rpc-all-probes.stp 
> semantic error: no match while resolving probe point module("sunrpc").function("rpc_new_client").return
> semantic error: no match while resolving probe point sunrpc.clnt.create_client.return
> semantic error: no match while resolving probe point module("sunrpc").function("rpc_release_task").return
> semantic error: no match while resolving probe point sunrpc.sched.release_task.return
> Pass 2: analysis failed.  Try again with another '--vp 01' option.
> 
> Now when I use a 2.6.34 kernel compiled with the '-fno-inline-functions-called-once'
> flag (which turns off inline-ing when routines are called from only one place)
> the run-tap does not fail. And sure enough, both rpc_new_client() and
> rpc_release_task() are only called from one place. 
> 
> So is there a work-around for this or should I just post the minor
> changes I have and move on?

I started looking into the same thing the other day.  I wondered: since
those functions are only called from one place, why not just probe the
caller?  In the case of 'rpc_new_client', the caller is 'rpc_create' (in
2.6.34) or 'rpc_create_client' (in 2.6.18).

The answer is probably just that the rpc tapset hasn't seen much work
since 2007.

If you'd like to take a stab at fixing the rpc tapset, go ahead.  If
not, I may take a deeper look later.

-- 
David Smith
dsmith@redhat.com
Red Hat
http://www.redhat.com
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