Message-ID: <52E76997.40303@nod.at>
Date: Tue, 28 Jan 2014 09:25:59 +0100
From: Richard Weinberger <richard@nod.at>
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To: Ingo Molnar <mingo@kernel.org>, Kees Cook <keescook@chromium.org>
CC: "H. Peter Anvin" <hpa@linux.intel.com>, "H. Peter Anvin" <hpa@zytor.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Cong Ding <dinggnu@gmail.com>, Ingo Molnar <mingo@elte.hu>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Mathias Krause <minipli@googlemail.com>,
        Michael Davidson <md@google.com>, Thomas Gleixner <tglx@linutronix.de>,
        Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Subject: Re: [GIT PULL] x86/kaslr for v3.14
References: <201401201647.s0KGlZdh004167@tazenda.hos.anvin.org> <CAFLxGvxO1MPDDjEh3FU5Gv2-eb6zBJxYtTnKdABDTTpbMxxYAw@mail.gmail.com> <52E5EFAF.3060609@linux.intel.com> <CAFLxGvxJ0A6hZ52RWffkg_zXXScyPn10P4HcKvdAXfE43h32Eg@mail.gmail.com> <CAGXu5jLcy9R_N_FQHMFheVTYSB9uobd-Orh7spEmpMaMXDtwEQ@mail.gmail.com> <52E6954F.2060303@nod.at> <CAGXu5jKXqUhTdhX_n8xSe+d3sPmZ0SK-aTQh2jCXWL6TgA5o=w@mail.gmail.com> <20140128062806.GA20750@gmail.com>
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Am 28.01.2014 07:28, schrieb Ingo Molnar:
> 
> * Kees Cook <keescook@chromium.org> wrote:
> 
>> On Mon, Jan 27, 2014 at 9:20 AM, Richard Weinberger <richard@nod.at> wrote:
>>> Am 27.01.2014 18:05, schrieb Kees Cook:
>>>> I would argue that decoding a non-panic oops on a running system is
>>>> entirely possible as-is, since the offset can be found from
>>>> /proc/kallsyms as root. It was the dead system that needed the offset
>>>> exported: via text in the panic, or via an ELF note in a core.
>>>
>>> The problem is that you have to pickup information from two sources.
>>> As a kernel developer users/customers often show you a backtrace (oops or panic)
>>> and want you do find the problem.
>>> They barley manage it copy&paste the topmost full trace from dmesg or /var/log/messages.
>>> If I have to ask them a bit later to tell me the offset from /proc/kallsyms or something else
>>> I'm lost. Mostly because they have already rebooted the box...
>>
>> As long as I can turn it off, I'd be happy. :)
>> /proc/sys/kernel/kaslr_in_oops or something?

Would be nice to have! :)

> Yeah, as long as it decodes by default.

Yep.
I like Ingo's idea (capital letters as indicators).
Are we all fine with that?

Thanks,
//richard
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