Re: [PATCH v6] mm/hugetlb: ignore hugepage kernel args if hugepages are unsupported

David Hildenbrand (Red Hat)
2025-12-22T10:28:51Z

On 12/22/25 06:57, Sourabh Jain wrote:
>
>
> On 22/12/25 08:42, Ritesh Harjani (IBM) wrote:
>> "David Hildenbrand (Red Hat)" <david@kernel.org> writes:
>>
>>>> Coming back to the fixes tag. I did mention a bit of a history [2] of
>>>> whatever I could find while reviewing this patch. I am not sure whether
>>>> you have looked into the links shared in that email or not. Here [2]:
>>>>
>>>> [2]: https://lore.kernel.org/linuxppc-dev/875xa3ksz9.ritesh.list@gmail.com/
>>>>
>>>> Where I am coming from is.. The current patch is acutally a partial
>>>> revert of the patch mentioned in the fixes tag. That means if this patch
>>>> gets applied to the older stable kernels, it would end up bringing the
>>>> same problem back, which the "Fixes" tagged patch is fixing in the 1st
>>>> place, isnt' it? See this discussion [3]...
>>>>
>>>> [3]: https://lore.kernel.org/all/b1f04f9f-fa46-c2a0-7693-4a0679d2a1ee@oracle.com/T/#m0eee87b458d93559426b8b0e78dc6ebcd26ad3ae
>>>>
>>>> ... So, IMO - the right fixes tag, if we have to add, it should be the
>>>> patch which moved the hpage_shift initialization to happen early i.e. in
>>>> mmu_early_init_devtree. That would be this patch [4]:
>>>>
>>>> [4]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2354ad252b66695be02f4acd18e37bf6264f0464
>>>>
>>>> Now, it's not really that the patch [4] had any issue as such. But it
>>>> seems like, that the current fix can only be applied after patch [4] is
>>>> taken.
>>>>
>>>> Do we agree?
>>> I think we should document all that in the cover letter, an describe
>>> that this partial revert is only possible after [4],
>> Yes, I agree. Let's add the above details in the commit msg.
>>
>>> and that that must
>>> be considered when attempting any kind of stable backports.
>> Sure. I would prefer if we change the Fixes tag to the one which I
>> pointed in above [4] (with explaination in the commit msg). However I am
>> still ok if we would like to retain the existing fixes tag and show [4]
>> as a dependency.
>
> I think we should keep the current Fixes tag with an explanation for
> dependency
> on [1] in the commit message.
>
> Would anyone have a different view?

Whatever introduced the issue should be called out in the Fixes tag; if
there are dependencies for the fix through other patches that were
already merged, that can be documented in the patch description
(relevant for stable or distro backports only).

--
Cheers

David