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

[Masami Hiramatsu]

(2013/11/16 2:46), Geert Uytterhoeven wrote:
> 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.

Ah, thanks! I'll fix that.
BTW, should I add CONFIG_HAVE_ENTRY_TEXT for x86 and use it
or just use CONFIG_X86 to detect it?

Thank you,

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


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