Re: Stap is translating to functions in __exit sections...and later module load fails

[Keshavamurthy Anil S <anil dot s dot keshavamurthy at intel dot com>]

On Fri, Oct 13, 2006 at 02:26:44PM -0700, Stone, Joshua I wrote:
> On Friday, October 13, 2006 1:51 PM, Keshavamurthy, Anil S wrote:
> > On Fri, Oct 13, 2006 at 02:02:39PM -0700, Stone, Joshua I wrote:
> >> The translator blacklist tries to avoid such functions by checking
> >> the section name -- anything within a section beginning with
> >> '.exit.' (e.g., .exit.text) is blacklisted, and thus won't match a
> >> function("*"). 
> > Exactly, I expected that the translator blacklists' and does not
> > elaborate such functions. But looks like this is not happening.
> > 
> > See here....
> > #stap -p2 -e 'probe kernel.function("*") {}' | sort | uniq |grep
> > exit_pfm_fs
> > kernel.function("exit_pfm_fs@arch/ia64/kernel/perfmon.c:1507"), 
> 
> Yes, I believe you that the translator is producing a hit for
> exit_pfm_fs.  The question is *why*.  Can you use objdump on your
> vmlinux to find out what section that function is actually in?
> 
> $ objdump -t <...>/vmlinux | grep exit_pfm_fs
> 
> On x86 and x86_64, functions decorated with __exit end up in
> '.exit.text'.  If this isn't the case for IA64, then we'll need a
> different mechanism for detecting such functions from the translator.

Looks like this is in .exit.text section
[root@csdor-tiger1 linux-2.6.19-rc1]# objdump -t arch/ia64/kernel/perfmon.o |grep exit_pfm_fs
0000000000000000 l     F .exit.text     0000000000000070 exit_pfm_fs

However "objdump -t vmlinux| grep exit_pfm_fs" did not show any thing.

-thanks,
Anil Keshavamurthy




> 
> 
> Josh