Re: [PATCH 1/1] ACPI: fix acpi table use after free

David Hildenbrand
2021-03-10T19:11:46Z

>>> Memory gets allocated and used in a different order, which seems to have
>>> exposed (yet another) latent BUG.
>>
>> Well, you can call it that, or you can say that things worked under
>> certain assumptions regarding the memory allocation order which are
>> not met any more.
>>
>>> The same could be reproduced via zone shuffling with a little luck.
>>
>> But nobody does that in practice.
>>

Dan will most certainly object. And I don't know what makes you speak in
absolute words here.

>> This would be relatively straightforward to address if ACPICA was not
>> involved in it, but unfortunately that's not the case.
>>
>> Changing this part of ACPICA is risky, because such changes may affect
>> other OSes using it, so that requires some serious consideration.
>> Alternatively, the previous memory allocation order in Linux could be
>> restored.
>
> Of course, long-term this needs to be addressed in the ACPI
> initialization code, because it clearly is not robust enough, but in
> the meantime there's practical breakage observable in the field, so
> what can be done about that?

*joke* enable zone shuffling.

No seriously, fix the latent BUG. What again is problematic about
excluding these pages from the page allcoator, for example, via
memblock_reserve()?

@Mike?

--
Thanks,

David / dhildenb