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Re: [PATCH v3 -tip] [BUGFIX] x86/kprobes: Fix to recover instructions on optimized path
(2012/02/28 18:59), Ingo Molnar wrote:
>
> * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> wrote:
>
>> (2012/02/28 17:48), Ingo Molnar wrote:
>>>
>>> * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> wrote:
>>>
>>>> (2012/02/27 18:34), Ingo Molnar wrote:
>>>>>
>>>>> * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> wrote:
>>>>>
>>>>>> +
>>>>>> +#ifdef CONFIG_OPTPROBES
>>>>>> +static unsigned long __recover_optprobed_insn(struct kprobe *kp,
>>>>>> + kprobe_opcode_t *buf,
>>>>>> + unsigned long addr)
>>>>>> +{
>>>>>> + long offs = addr - (unsigned long)kp->addr - 1;
>>>>>> + struct optimized_kprobe *op = container_of(kp, struct optimized_kprobe, kp);
>>>>>> +
>>>>>> + /*
>>>>>> + * If the kprobe can be optimized, original bytes which can be
>>>>>> + * overwritten by jump destination address. In this case, original
>>>>>> + * bytes must be recovered from op->optinsn.copied_insn buffer.
>>>>>> + */
>>>>>> + memcpy(buf, (void *)addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
>>>>>> + if (addr == (unsigned long)kp->addr) {
>>>>>> + buf[0] = kp->opcode;
>>>>>> + memcpy(buf + 1, op->optinsn.copied_insn, RELATIVE_ADDR_SIZE);
>>>>>> + } else
>>>>>> + memcpy(buf, op->optinsn.copied_insn + offs, RELATIVE_ADDR_SIZE - offs);
>>>>>> +
>>>>>> + return (unsigned long)buf;
>>>>>> +}
>>>>>> +#endif
>>>>>
>>>>> Why not stick this into a new kprobes-opt.c file?
>>>>
>>>> Would you mean that I should split all optprobe stuffs into
>>>> new file?
>>>
>>> Yeah, that would be sensible I think - and it might help avoid
>>> similar complications in the future.
>>>
>>> Could (and probably should) be done in a separate patch - to
>>> keep the bits that you already fixed and tested intact.
>>
>> OK, I'll make a separate patch.
>
> Could be done on top of your existing patch, to keep things
> simpler for you - a split-up patch done before your fix would
> create a lot of conflicts in the fix patch.
I see. And in the previous patch, I've just find a small
racing bug. I'll update it too.
Thank you,
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com