Bootfs got overwritten

[Mai, Haohui]

Hi,

I probably should include the full logs here. You can see that it
breaks the code because the module lists are not sorted by grub.

  moving module 16 { 2835000-296ac76 } -> { 3803000-3938c76 }
  moving module 15 { 2470000-2835000 } -> { 343e000-3803000 }
  moving module 14 { 1c70000-2470000 } -> { 2c3e000-343e000 }
  moving module 13 { 187c000-1c6f98a } -> { 284a000-2c3d98a }
  moving module 12 { 187b000-187b618 } -> { 2849000-2849618 }
  moving module 11 { 29d000-29d3b7 } -> { 126b000-126b3b7 }
  moving module 10 { 2cf000-2cfaa4 } -> { 129d000-129daa4 }
  moving module 09 { 1708000-187aa94 } -> { 26d6000-2848a94 }
  moving module 08 { 135c000-1707411 } -> { 232a000-26d5411 }
  moving module 07 { 1259000-135b7b8 } -> { 2227000-23297b8 }
  moving module 06 { 85c000-1258bde } -> { 182a000-2226bde }
  moving module 05 { 629000-85b826 } -> { 15f7000-1829826 }
  moving module 04 { 503000-628310 } -> { 14d1000-15f6310 }
  moving module 03 { 2e2000-5029b4 } -> { 12b0000-14d09b4 }
  moving module 02 { 193000-1e69f5 } -> { 1161000-11b49f5 }
  moving module 01 { 132000-192880 } -> { 1100000-1160880 }

~Haohui

On Thu, Apr 19, 2012 at 5:58 PM, Mai, Haohui <haohui.mai at gmail.com> wrote:
> It turns out that bootstrap overwrites the memory during relocation.
> Here are the logs:
>
>  moving module 11 { 29d000-29d3b7 } -> { 126b000-126b3b7 }
> ...
>  moving module 07 { 1259000-135b7b8 } -> { 2227000-23297b8 }
> ...
>
> Module 07 is the rtc module, which is the module has been overwritten.
> As you can see that module 11 overwrite the page 0x126b000 before
> moving module 07, which causes the corruption.
>
> The detection in bootstrap doesn't seem to be sufficient since it only
> detects whether the new region is overlapped to roottask and sigma0.
>
> What would be the best way of fixing it?
>
> ~Haohui
>
> On Thu, Apr 19, 2012 at 1:46 PM, Haohui Mai <haohui.mai at gmail.com> wrote:
>> What is more interesting is that only that page is overwritten: The page before and after it stays the same.
>>
>> ~Haohui
>>
>> On Apr 19, 2012, at 1:40 PM, Haohui Mai wrote:
>>
>>> Hi,
>>>
>>> I'm encountering a problem where the memory region of BOOTFS of L4Re got overwritten. Interestingly, the page is overwritten by things in the bootfs.
>>>
>>> Here are the physical memory mapping set up by BOOTFS:
>>>
>>> ...
>>>  BOOTFS: [2227000-23297b8] [C:506000] rtc
>>>  BOOTFS: [232a000-26d5411] [C:507000] mag
>>>  BOOTFS: [26d6000-2848a94] [C:508000] fb-drv
>>>  BOOTFS: [129d000-129daa4] [C:509000] vandroid-x86.cfg
>>>  BOOTFS: [126b000-126b3b7] [C:50a000] x86-legacy.devs
>>> …
>>>
>>> The page 0x2239000 (which belongs to rtc) is magically overwritten by the first page of x86-legacy.devs. I confirmed it with both JDB and QEMU monitor.
>>>
>>> I'm running the newest snapshot of L4Re / L4Android on top of the UP version L4.Fiasco kernel.
>>>
>>> What would be the best approach to debug the problem? is it there a way to mark the whole BOOTFS as read-only so that I can figure out what's going on?
>>>
>>> Thanks!
>>>
>>> ~Haohui
>>