Subject: Re: [x86-tip] RSDP changes converted i4790 box SMP -> UP
To: Gabriel C <nix.or.die@gmail.com>, Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>,
        Mike Galbraith <mgalbraith@suse.de>,
        LKML <linux-kernel@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Peter Zijlstra <peterz@infradead.org>
References: <20180111133723.d7x3sekanz5jhut2@gmail.com>
 <1515682631.16805.3.camel@suse.de>
 <20180111150331.7zzkd7awdxele54b@gmail.com>
 <20180111151044.GC6176@hirez.programming.kicks-ass.net>
 <1515694412.7054.10.camel@suse.de> <1515731128.10188.32.camel@suse.de>
 <20180112131144.bkopj2ooslwdyvoz@gmail.com>
 <0af5f083-b659-6c67-1ceb-a2bf9108c879@suse.com>
 <20180115145615.m54ewqg7vmvp4akj@pd.tnic>
 <b2a941a3-ff75-d57a-6dac-9a91fb0f4c31@suse.com>
 <20180115153243.3wst57a2fqin2h37@gmail.com>
 <c4b9a536-d889-4429-76a5-a9fdd5f6234b@suse.com>
 <f810f818-7eed-5856-c9db-9ae6f68f6586@gmail.com>
 <ff0d07e9-282e-f6f4-a7c6-8b61012d3f4f@suse.com>
 <3e29151d-0afc-c874-3e5e-557403ad10d3@gmail.com>
From: Juergen Gross <jgross@suse.com>
Message-ID: <22bf2090-4319-080c-504d-8e38a9b67af1@suse.com>
Date: Mon, 15 Jan 2018 18:04:36 +0100
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On 15/01/18 17:56, Gabriel C wrote:
> On 15.01.2018 17:42, Juergen Gross wrote:
>> On 15/01/18 17:29, Gabriel C wrote:
>>> On 15.01.2018 16:40, Juergen Gross wrote:
>>>> On 15/01/18 16:32, Ingo Molnar wrote:
>>>>>
>>>
>>> Hi Juergen,
>>>
>>>>> * Juergen Gross <jgross@suse.com> wrote:
>>>>>
>>>>>> On 15/01/18 15:56, Borislav Petkov wrote:
>>>>>>> On Mon, Jan 15, 2018 at 03:52:25PM +0100, Juergen Gross wrote:
>>>>>>>> Ingo, with my finding that above boot failure is related to a
>>>>>>>> bug in
>>>>>>>> openSUSE's grub2 (I've verified it soesn't exist in upstream
>>>>>>>> grub2),
>>>>>>>
>>>>>>> The box I'm seeing this on has SLES12-SP2 grub:
>>>>>>>
>>>>>>> Version        : 2.02~beta2-115.9.1
>>>>>>>
>>>>>>> Does it have the same bug?
>>>>>>
>>>>>> The patch introducing this problem is from 2012. So I guess: yes.
>>>>>
>>>>> I suspect this makes it a widespread, unintended ABI. Can we detect
>>>>> and somehow avoid it?
>>>>>
>>>>> The boot protocol ABI sucks if it's fragile against such mistakes.
>>>>
>>>> Well, copying sizeof(setup_header) into grub2 and then coyping back
>>>> just
>>>> 1024 bytes is plain wrong. It is a miracle nothing broke up to now.
>>>>
>>>
>>> I'm not on SUSE and hit that too on an H11DSi-NT.
>>> See: https://marc.info/?l=linux-kernel&m=151579540320553&w=2
>>
>> Where does your grub come from?
> 
> https://github.com/frugalware/frugalware-current/tree/master/source/base/grub2
> 
> 
> 

See line 409 of:

https://github.com/frugalware/frugalware-current/blob/master/source/base/grub2/0019-Add-support-for-linuxefi.patch

There you can see the memcpy with the wrong size back to the to be
booted kernel...


Juergen