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Re: [PATCH -tip v3 0/2] kprobes/x86: Another way to make insn buffer RO and cleanup

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  Re: [PATCH -tip v3 0/2] kprobes/x86: Another way to make insn  buffer RO and cleanup Masami Hiramatsu <mhiramat@kernel.org> - 2017-08-28 04:30 +0200

#1720976 — Re: [PATCH -tip v3 0/2] kprobes/x86: Another way to make insn buffer RO and cleanup

Hi Ingo,

What would you think about fixing this way?
This makes the instruction buffer always RO and
poke it via text_poke.

Thank you,

On Fri, 18 Aug 2017 17:22:54 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:

> Hi,
> 
> This series modifies how to handle RO insn buffer and
> cleans up addressof operators.
> 
> The 1st patch changes the RO insn buffer handling: instead
> of using set_memory_ro/rw to modify the buffer, it prepares
> new instructions in another buffer and write it with
> text_poke() as suggested by Ingo Molnar (Thanks!).
> Since the text_poke() is safely modifying code by
> mapping alias pages, it can write RO pages.
> This also override alloc_insn_page() so that it returns
> ROX page directly.
> 
> The 2nd one is not changed. It is a cleanup patch
> to remove addressof operators ("&") since
> it is meaningless anymore.
> 
> V3 has just a following update:
>  - [1/2] Not to just add set_memory_ro(), introduce new
>    patch to change the way to handle RO pages.
> 
> Thanks,
> 
> ---
> 
> Masami Hiramatsu (2):
>       kprobes/x86: Make insn buffer always ROX and use text_poke
>       kprobes/x86: Remove addressof operators
> 
> 
>  arch/x86/include/asm/kprobes.h   |    4 +-
>  arch/x86/kernel/kprobes/common.h |    6 ++-
>  arch/x86/kernel/kprobes/core.c   |   61 +++++++++++++++++++++------------
>  arch/x86/kernel/kprobes/opt.c    |   71 +++++++++++++++++++++-----------------
>  kernel/kprobes.c                 |    2 +
>  5 files changed, 86 insertions(+), 58 deletions(-)
> 
> --
> Masami Hiramatsu <mhiramat@kernel.org>


-- 
Masami Hiramatsu <mhiramat@kernel.org>

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