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Re: Re: [PATCH -tip v8 10/26] kprobes/x86: Allow probe on some kprobe preparation functions


(2014/03/25 4:35), Steven Rostedt wrote:
> On Wed, 05 Mar 2014 20:59:53 +0900
> Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> wrote:
> 
>> There is no need to prohibit probing on the functions
>> used in preparation phase. Those are safely probed because
>> those are not invoked from breakpoint/fault/debug handlers,
>> there is no chance to cause recursive exceptions.
>>
>> Following functions are now removed from the kprobes blacklist.
>>  can_boost
>>  can_probe
>>  can_optimize
>>  is_IF_modifier
>>  __copy_instruction
>>  copy_optimized_instructions
>>  arch_copy_kprobe
>>  arch_prepare_kprobe
>>  arch_arm_kprobe
>>  arch_disarm_kprobe
>>  arch_remove_kprobe
> 
> Is there any possibility that the arm and disarm could cause issues if
> we have a probe in the middle of setting it?
> 
> I guess not, but I just wanted to ask, as your test only tested the
> start of function and not the middle of it.

OK, I've tested it by attached script which adds probes on every address
of the target function and run a testcase(register/unregister other probes),
and found no problem. :)

Thank you,


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



Attachment: kprobes_test.sh
Description: Text document


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