systemtap for ixgbe driver on Fedora

[Carol Liu - Sun Microsystems - Beijing China]

Hi :
I  tried to trace some function the driver/net ixgbe by systemtap, but 
it always fails with following errors:
[root@petpig demo]# lsmod|grep ixgbe
ixgbe                 106084  1
dca                     5152  1 ixgbe
mdio                    3772  1 ixgbe

[root@petpig demo]# cat ixgbe.stp
probe kernel.function("ixgbe_fcoe_ddp_put") { log ("enter") }
probe kernel.function("ixgbe_fcoe_ddp_put").return { log ("exit") }

[root@petpig demo]# stap -v ixgbe.stp
Pass 1: parsed user script and 59 library script(s) in 
150usr/10sys/166real ms.
semantic error: no match while resolving probe point 
kernel.function("ixgbe_fcoe_ddp_put")
semantic error: no match while resolving probe point 
kernel.function("ixgbe_fcoe_ddp_put").return
Pass 2: analyzed script: 0 probe(s), 0 function(s), 0 embed(s), 0 
global(s) in 420usr/30sys/458real ms.
Pass 2: analysis failed.  Try again with another '--vp 01' option.

root@petpig demo]# stap -V
SystemTap translator/driver (version 0.9.9/0.141 non-git sources)
Copyright (C) 2005-2009 Red Hat, Inc. and others
This is free software; see the source for copying conditions.

The self-build kernel version is 2.6.31.

Anyone give me some hint ?  really really appreciate that. :)

/Carol