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Re: Why can't I access 'kill_something_info' probes?


Wenji Huang wrote:
Om wrote:
Hi,
Eliding unused function stp_print_binary
semantic error: failed to retrieve location attribute for local 'info' (dieoffset: 0x334d03): identifier '$info' at ./killtrace.stp:10:32
semantic error: failed to retrieve location attribute for local 'info' (dieoffset: 0x334d03): identifier '$info' at ./killtrace.stp:11:32
Pass 2: analyzed script: 3 probe(s), 4 function(s), 0 embed(s), 0 global(s) in 580usr/150sys/732real ms.

Seems this function is implicitly inlined. To access parameters of
How do we know that? What should I look for?
inline functions is still pending problem for systemtap/gcc. But you can
try marker to get the inline function parameter information.

For your case, I found kill_something_info is just called in sys_kill
and always info.si_signo = sig; info.si_errno = 0 in kill_something_info
entry. So no necessary to do another probe. just sys_kill is enough.
Yeah.. I was curious why I could not probe.

BTW: probe kernel.function("sys_kill").return could be the reference to the result of signal dispatch.
Thanks for the suggestion. I am just poking the kernel. I know the values of info->*, but when I got the error, I wanted to know if I was doing something wrong. and that gave a little more knowledge :-D

Thanks,
Om.


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