Re: [x86-tip] RSDP changes converted i4790 box SMP -> UP

[Juergen Gross]

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@xxxxxxxx> 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:
>>>>>>>
>>>>>>> VersionÂÂÂÂÂÂÂ : 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