Re: [PATCH -tip v4 0/6] kprobes: introduce NOKPROBE_SYMBOL() and fixes crash bugs

[Sandeepa Prabhu <sandeepa dot prabhu at linaro dot org>]

On 4 December 2013 13:09, Masami Hiramatsu
<masami.hiramatsu.pt@hitachi.com> wrote:
> (2013/12/04 11:54), Sandeepa Prabhu wrote:
>> On 4 December 2013 06:58, Masami Hiramatsu
>> <masami.hiramatsu.pt@hitachi.com> wrote:
>>> Hi,
>>> Here is the version 4 of NOKPORBE_SYMBOL series.
>>>
>>> In this version, I removed the cleanup patches and
>>> add bugfixes I've found, since those bugs will be
>>> critical.
>>> Rest of the cleanup and visible blacklists will be
>>> proposed later in another series.
>>>
>>> Oh, just one new thing, I added a new RFC patch which
>>> removes the dependency of notify_die() from kprobes
>>> miss-hit/recovery path. Since the notify_die() involves
>>> locking and lockdep code which invokes a lot of heavy
>>> printk functions etc. This helped me to minimize the
>>> blacklist and provides more stability for kprobes.
>>> Actually, most of int3 handlers are already called
>>> from do_int3 directly, I think this change is acceptable
>>> too.
>>>
>>> Here is the updates about NOKPROBE_SYMBOL().
>>>  - Now _ASM_NOKPROBE() macro is introduced for assembly
>>>    symbols on x86.
>>>  - Rename kprobe_blackpoint to kprobe_blacklist_entry
>>>    and simplify it. Also NOKPROBE_SYMBOL() macro just
>>>    saves the address of non-probe-able symbols.
>>>
>>> ---
>>>
>>> Masami Hiramatsu (6):
>>
>>>       kprobes: Prohibit probing on .entry.text code
>>>       kprobes: Introduce NOKPROBE_SYMBOL() macro for blacklist
>> Hi Masami,
>> Is it good idea to split  "arch/x86" code from generic kernel changes?
>> Then we just need to take above two patches for verifying it on arm64
>> or other platforms.
>
> Yeah, it can be.
> However I think you can apply it without any problem on arm64 tree too,
> since it "just adds" an asm macro in arch/x86/include/asm/asm.h.
> It should not have any effect for other arch. Could you try it? :)
Hmm, for the second patch, git am failed with: "error: patch failed:
kernel/sched/core.c:2662",
manually patched to resolve it.  aarch64 tree is right now at Linux 3.13-rc2.

Anyways, no conflicts for x86 arch files.

Thanks,
Sandeepa

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