This is the mail archive of the
systemtap@sourceware.org
mailing list for the systemtap project.
Re: Re: [PATCH -tip v4 0/6] kprobes: introduce NOKPROBE_SYMBOL() and fixes crash bugs
- From: Masami Hiramatsu <masami dot hiramatsu dot pt at hitachi dot com>
- To: Sandeepa Prabhu <sandeepa dot prabhu at linaro dot org>
- Cc: Ingo Molnar <mingo at kernel dot org>, Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, x86 at kernel dot org, lkml <linux-kernel at vger dot kernel dot org>, "Steven Rostedt (Red Hat)" <rostedt at goodmis dot org>, systemtap at sourceware dot org, "David S. Miller" <davem at davemloft dot net>
- Date: Thu, 05 Dec 2013 08:32:13 +0900
- Subject: Re: Re: [PATCH -tip v4 0/6] kprobes: introduce NOKPROBE_SYMBOL() and fixes crash bugs
- Authentication-results: sourceware.org; auth=none
- References: <20131204012841 dot 22118 dot 82992 dot stgit at kbuild-fedora dot novalocal> <CA+b37P3R7r6DoJCX7GQD+BREGsb+s2WBc71c03TVFCPi6=-mkw at mail dot gmail dot com> <529EDC14 dot 5070700 at hitachi dot com> <CA+b37P1msx3fSEe_UG=oR458fOoryv=Y_kv5Hg+HzofzgT8KZg at mail dot gmail dot com>
(2013/12/04 17:46), Sandeepa Prabhu wrote:
> 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.
Ah I see, that must be changed because it is the change related to introducing
new blacklist itself. It is not solved by splitting arch/x86 change.
Thank you,
--
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com