From mboxrd@z Thu Jan  1 00:00:00 1970
From: Geert Uytterhoeven <geert@linux-m68k.org>
Subject: Re: [PATCH -tip RFC v2 01/22] kprobes: Prohibit probing on
 .entry.text code
Date: Fri, 15 Nov 2013 18:46:40 +0100
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To: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>, Ingo Molnar <mingo@kernel.org>, Linux-Arch <linux-arch@vger.kernel.org>, Ananth N Mavinakayanahalli <ananth@in.ibm.com>, Peter Zijlstra <peterz@infradead.org>, Frederic Weisbecker <fweisbec@gmail.com>, the arch/x86 maintainers <x86@kernel.org>, lkml <linux-kernel@vger.kernel.org>, virtualization@lists.linux-foundation.org, Ingo Molnar <mingo@redhat.com>, Al Viro <viro@zeniv.linux.org.uk>, "H. Peter Anvin" <hpa@zytor.com>, Thomas Gleixner <tglx@linutronix.de>, Seiji Aguchi <seiji.aguchi@hds.com>, "David S. Miller" <davem@davemloft.net>

On Fri, Nov 15, 2013 at 5:43 PM, Steven Rostedt <rostedt@goodmis.org> wrote:
> On Fri, 15 Nov 2013 04:53:18 +0000
> Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> 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@linux-m68k.org

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