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Re: [PATCH -tip v6 06/22] [BUGFIX] x86: Prohibit probing on memcpy/memset
- From: Masami Hiramatsu <masami dot hiramatsu dot pt at hitachi dot com>
- To: Jovi Zhangwei <jovi dot zhangwei at gmail dot com>
- Cc: Ingo Molnar <mingo at kernel dot org>, linux-arch at vger dot kernel dot org, Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, Sandeepa Prabhu <sandeepa dot prabhu at linaro dot org>, x86 at kernel dot org, lkml <linux-kernel at vger dot kernel dot org>, "Steven Rostedt (Red Hat)" <rostedt at goodmis dot org>, Ingo Molnar <mingo at redhat dot com>, systemtap at sourceware dot org, "H. Peter Anvin" <hpa at zytor dot com>, Thomas Gleixner <tglx at linutronix dot de>, "David S. Miller" <davem at davemloft dot net>
- Date: Wed, 25 Dec 2013 00:58:02 +0900
- Subject: Re: [PATCH -tip v6 06/22] [BUGFIX] x86: Prohibit probing on memcpy/memset
- Authentication-results: sourceware.org; auth=none
- References: <20131219090353 dot 14309 dot 15496 dot stgit at kbuild-fedora dot novalocal> <20131219090409 dot 14309 dot 25677 dot stgit at kbuild-fedora dot novalocal> <CAGdX0WFKYHqXrVQ6LBw0YgH_H6cP=LZVCBe1iOvEXsHQPD8Zmg at mail dot gmail dot com> <52B3AD7D dot 2020104 at hitachi dot com> <CAGdX0WENxTPhFDtcEW6LFhk1SNZc6mEK+JsCDOJmfK8_PS1rxg at mail dot gmail dot com> <52B3CABE dot 1080903 at hitachi dot com> <CAGdX0WEev84sOyu-uzkDOmQFi_=mza7cPzyC0VkRZe0fD_1+jQ at mail dot gmail dot com> <52B40C00 dot 2060401 at hitachi dot com> <CAGdX0WECaJBSX29-+fC=0XLJfAh0JvFyLTW2V8yM616L45iCQQ at mail dot gmail dot com> <52B8178F dot 5020607 at hitachi dot com> <CAGdX0WEZue1fBtHw058HAmuCktkM+jyKdPfn0ZM2=fNAPfcJwA at mail dot gmail dot com> <52B9468D dot 4060201 at hitachi dot com> <CAGdX0WH=QvXMUfSL7-eXHWLM7VLPDus2=jFGCyJcK6Px-t0bng at mail dot gmail dot com>
(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