Re: [PATCH] mm/page_vma_mapped: guard check_pmd() with CONFIG_TRANSPARENT_HUGEPAGE

[Balbir Singh]

On 6/25/26 16:41, Wei Yang wrote:
> +cc Balbir
> 
> On Wed, Jun 24, 2026 at 09:59:43PM -0700, Andrew Morton wrote:
>> On Thu, 25 Jun 2026 03:46:29 +0000 Wei Yang <richard.weiyang@xxxxxxxxx> wrote:
>>
>>>> Sashiko had an off-topic complaint about the surrounding code:
>>>> 	https://lore.kernel.org/oe-kbuild-all/202606240042.ffPsEXVc-lkp@xxxxxxxxx/
>>>
>>> I see this robot reply, but not see the Sashiko comment.
>>>
>>> How can I view Sashiko's commnet?
>>
>> oop sorry.
>>
>> You can go to https://sashiko.dev/ and search for the email subject. 
>>
>> Or append your Message-ID to "https://sashiko.dev/#/patchset":
>>
>> 	https://sashiko.dev/#/patchset/20260624082359.2869-1-richard.weiyang@xxxxxxxxx
>>
> 
> Got it, thansk
> 
> This one mentioned two things:
> 
>   a. page_vma_mapped_walk() return without check
>   b. whether __split_huge_pmd_locked() would split device-private pmd
> 
> For a., it is being fixing at [1].
> 
> For b., to be honest I am not 100% for sure. If a device-private pmd could be
> file backed, then this looks like a bug.
> 
> Balbir,
> 
> Would you mind taking a look at the second comment raised by Sashiko?
> 
> [1]: https://lore.kernel.org/linux-mm/20260624065353.1622-1-richard.weiyang@xxxxxxxxx/
> 

device-private pmd's are not file backed

Balbir