Re: Semantic error while accessing a function parameter with linux 2.6.29 ppc64

[Sridhar Samudrala <samudrala dot sridhar at gmail dot com>]

On Thu, Mar 26, 2009 at 5:06 PM, Frank Ch. Eigler <fche@redhat.com> wrote:
>
> Sridhar Samudrala <samudrala.sridhar@gmail.com> writes:
>
>> The following simple one line script is failing with a semantic error
>> on linux 2.6.29 ppc64 .
>> The same script works fine on linux 2.6.28.
>> Is there any new config option that needs to be enabled with 2.6.29?
>>
>> stap -e 'probe kernel.function("tcp_transmit_skb") { printf("skb:%p \n",$sk=
>> b) }'
>>
>> semantic error: not accessible at this address: identifier '$skb' [...]
>
> http://sources.redhat.com/systemtap/wiki/TipContextVariables has
> some advice about this general problem.

That link seems to be referring to bugs that are seen when probing
inline functions.
I am seeing this problem even with non-inline functions and only when
i moved to linux 2.6.29.
The same scripts run fine with linux 2.6.28 with the same level of gcc
$ gcc --version
gcc (GCC) 4.1.2 20080704 (Red Hat 4.1.2-44)

Thanks
Sridhar