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Date: Mon, 24 Mar 2014 15:35:56 -0400
From: Steven Rostedt <rostedt@goodmis.org>
To: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
        Andi Kleen <andi@firstfloor.org>,
        Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
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        "H. Peter Anvin" <hpa@zytor.com>, Thomas Gleixner <tglx@linutronix.de>,
        Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH -tip v8 10/26] kprobes/x86: Allow probe on some kprobe
 preparation functions
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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.

-- Steve


>  arch_trampoline_kprobe
>  arch_prepare_kprobe_ftrace
>  arch_prepare_optimized_kprobe
>  arch_check_optimized_kprobe
>  arch_within_optimized_kprobe
>  __arch_remove_optimized_kprobe
>  arch_remove_optimized_kprobe
>  arch_optimize_kprobes
>  arch_unoptimize_kprobe
>