Re: [PATCH -tip RFC v2 01/22] kprobes: Prohibit probing on.entry.text code

[Geert Uytterhoeven]

On Fri, Nov 15, 2013 at 5:43 PM, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> On Fri, 15 Nov 2013 04:53:18 +0000
> Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx> wrote:
>
>> .entry.text is a code area which is used for interrupt/syscall
>> entries, and there are many sensitive codes.
>> Thus, it is better to prohibit probing on all of such codes
>> instead of a part of that.
>> Since some symbols are already registered on kprobe blacklist,
>> this also removes them from the blacklist.
>
> This change only works with x86. On other archs, I get this:
>
> kernel/built-in.o: In function `register_kprobe':
> (.kprobes.text+0x9f4): undefined reference to `__entry_text_start'
> kernel/built-in.o: In function `register_kprobe':
> (.kprobes.text+0x9f8): undefined reference to `__entry_text_end'
> make[1]: *** [vmlinux] Error 1
> make: *** [sub-make] Error 2

X86 is the sole architecture that has ENTRY_TEXT in its
arch/*/kernel/vmlinux.lds.S.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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