Re: Re: [PATCH -tip v3 13/23] x86/trap: Use NOKPROBE_SYMBOL macro in trap.c

(2013/11/23 6:21), Andi Kleen wrote:

On Wed, Nov 20, 2013 at 04:22:21AM +0000, Masami Hiramatsu wrote:

quoted

Use NOKPROBE_SYMBOL macro to protect functions from kprobes
instead of __kprobes annotation in trap.c.
This also applies __always_inline annotation for some cases,
because NOKPROBE_SYMBOL() will inhibit inlining by referring
the symbol address.

NOKPROBE_SYMBOL seems to add a reference from some variable to the function?

With LTO we can optimize away unused functions, but not
when there are references to the symbol. So this would likely
prevent optimizations with LTO.

Hmm, indeed. I think I can remove the function reference if
the function name is unique, because the macro also stores the
name.
In that case, even if the function itself is optimized out and
there is no entry in kallsyms, we can just ignore it when init
the blacklist.

Thank you,

-- 
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com