Re: [PATCH] Revert "mm: fix MAX_FOLIO_ORDER on powerpc configs with hugetlb"

["David Hildenbrand (Red Hat)" <david@kernel.org>]

>> 39231e8d6ba7 simply shuffles ifdefs and Kconfig items, so I assume it
>> exposed a pre-existing bug.
>>
>> Reverting 39231e8d6ba7 will re-hide that bug.
> 
> Shuah confirmed that the bugs were on v6.18-rc6 and they were fixed in
> 6.18 [1].
> 
> I verified that reverting 39231e8d6ba7 from v6.18-rc6 does not solve
> anything, but applying 5bebe8de19264 does [2].
> 

Thanks!

> So reverting 39231e8d6ba7 does not change anything and there is no bug it
> hides. The bug was introduced by adfb6609c680 ("mm/huge_memory: initialise
> the tags of the huge zero folio"), was fixed by 5bebe8de1926
> ("mm/huge_memory: Fix initialization of huge zero folio") ...
> 
>> And that isn't a bad thing.  If we re-hide the bug in 6.18.x and in
>> mainline then that relieves the people who are hitting this and it
>> takes the pressure off David, Mike and yourself to get the underlying
>> bug fixed in a hurry.
>>
>> So I think I'll queue this as a hotfix, plan to send it Linuswards in a
>> couple of days.
>>
>> Or Linus may choose to apply it directly or to do a local revert of
>> 39231e8d6ba7.  But I don't see how a local revert will get communicated
>> to the 6.18.x maintainers.
>>
>> David, Linus, opinions please?
>>
>>> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
>>
>> Let's have a cc:stable here, just to be sure.
> 
> ... and we can skip all this hassle.

Yes.

Thinking about reverting arbitrary commits after Shuah clearly tested 
something wrong is completely unreasonable.

-- 
Cheers

David