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

[Sandeepa Prabhu <sandeepa.prabhu@linaro.org>]

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.

Thanks,
Sandeepa
>       [BUGFIX] kprobes/x86: Prohibit probing on debug_stack_*
>       [BUGFIX] x86: Prohibit probing on native_set_debugreg
>       [BUGFIX] x86: Prohibit probing on thunk functions and restore
>       [RFC] kprobes/x86: Call exception handlers directly from do_int3/do_debug
>
>
>  Documentation/kprobes.txt         |   16 +++++
>  arch/x86/include/asm/asm.h        |    7 ++
>  arch/x86/include/asm/kprobes.h    |    2 +
>  arch/x86/kernel/cpu/common.c      |    4 +
>  arch/x86/kernel/entry_32.S        |   33 -----------
>  arch/x86/kernel/entry_64.S        |   20 -------
>  arch/x86/kernel/kprobes/core.c    |   32 ++++------
>  arch/x86/kernel/paravirt.c        |    5 ++
>  arch/x86/kernel/traps.c           |   10 +++
>  arch/x86/lib/thunk_32.S           |    3 +
>  arch/x86/lib/thunk_64.S           |    3 +
>  include/asm-generic/vmlinux.lds.h |    9 +++
>  include/linux/kprobes.h           |   21 ++++++-
>  kernel/kprobes.c                  |  113 ++++++++++++++++++++-----------------
>  kernel/sched/core.c               |    1
>  15 files changed, 147 insertions(+), 132 deletions(-)
>
> --
> Masami HIRAMATSU
> IT Management Research Dept. Linux Technology Center
> Hitachi, Ltd., Yokohama Research Laboratory
> E-mail: masami.hiramatsu.pt@hitachi.com
>