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Date: Wed, 25 Dec 2013 00:58:02 +0900
From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Organization: Hitachi, Ltd., Japan
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To: Jovi Zhangwei <jovi.zhangwei@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>, linux-arch@vger.kernel.org,
        Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
        Sandeepa Prabhu <sandeepa.prabhu@linaro.org>, x86@kernel.org,
        lkml <linux-kernel@vger.kernel.org>,
        "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>,
        Ingo Molnar <mingo@redhat.com>, systemtap@sourceware.org,
        "H. Peter Anvin" <hpa@zytor.com>, Thomas Gleixner <tglx@linutronix.de>,
        "David S. Miller" <davem@davemloft.net>
Subject: Re: [PATCH -tip v6 06/22] [BUGFIX] x86: Prohibit probing on memcpy/memset
References: <20131219090353.14309.15496.stgit@kbuild-fedora.novalocal> <20131219090409.14309.25677.stgit@kbuild-fedora.novalocal> <CAGdX0WFKYHqXrVQ6LBw0YgH_H6cP=LZVCBe1iOvEXsHQPD8Zmg@mail.gmail.com> <52B3AD7D.2020104@hitachi.com> <CAGdX0WENxTPhFDtcEW6LFhk1SNZc6mEK+JsCDOJmfK8_PS1rxg@mail.gmail.com> <52B3CABE.1080903@hitachi.com> <CAGdX0WEev84sOyu-uzkDOmQFi_=mza7cPzyC0VkRZe0fD_1+jQ@mail.gmail.com> <52B40C00.2060401@hitachi.com> <CAGdX0WECaJBSX29-+fC=0XLJfAh0JvFyLTW2V8yM616L45iCQQ@mail.gmail.com> <52B8178F.5020607@hitachi.com> <CAGdX0WEZue1fBtHw058HAmuCktkM+jyKdPfn0ZM2=fNAPfcJwA@mail.gmail.com> <52B9468D.4060201@hitachi.com> <CAGdX0WH=QvXMUfSL7-eXHWLM7VLPDus2=jFGCyJcK6Px-t0bng@mail.gmail.com>
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(2013/12/24 18:53), Jovi Zhangwei wrote:
>>> Still no crash, use your kernel config.
>>> memcpy and __memcpy have same address in /proc/kallsyms.
>>>
>>> Looks like a interesting problem.
>>
>> Agreed. In my case, those have same address, but only probing
>> __memcpy caused a kernel crash. I'm not sure why, but it is
>> safe to disable probing on it.
>>
> Shall we need dig further to address the root cause? IMO, the kprobe
> should act same behavior when given same probe address, but it's look
> so weird in your box. :)

Hmm, right now, I tried it again and found the bug disappeared...

I'm using the latest tip kernel for the test;
3ab838d7723e9fbfd49b2d395752bd68e1ef4b71

Should I remove this patch until it happens again?

Thank you,


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