dwarfless failures on ppc64

[Srinivasa DS]

Jim Keniston wrote:
>>
>> [root@llm27lp1 src]# grep "sys_pipe" /proc/kallsyms
>> c0000000000fc410 W .sys_pipe2
>> c0000000000fc490 W .sys_pipe
>>
> 
> Oy.  You see this problem with --kmap, but not with --kelf, right?

Yes, I dont see this problem with --kelf option.

> 
> The problem with 'W' entries in nm listings is that some of them refer
> to "real" functions and some don't.  What I see during a little research
> today is... if multiple 'W' entries have the same address, none of them
> refer to symbols that stap considers probeable.  If it's the only 'W'
> entry with that address, stap will probe it.  I'm not sure why that is,
> but could you check this out on your system?  Something like...
> 
> awk '$2=="W" {print $3}' /proc/kallsyms > weak.stp
> 
> Then edit weak.stp so you have a
> 	kernel.function("funcname") ?,
> line for each weak function, with the result of
> probe
> 	kernel.function("f1") ?,
> 	kernel.function("f2") ?,
> 	...
> 	kernel.function("fN") ?
> {
> 	log(pp())
> }
> Then do
> 	stap -vv -p2 weak.stp > weak.p2 2>&1
> and see which functions get probed.
> 
> Maybe send me weak.stp, weak.p2, and a copy of /proc/kallsyms?

o.k, I will send it.

Thanks
  Srinivasa DS