Re: [PATCH v4 6/6] mm/mm_init: add zone mismatch warning during page init

[Muchun Song]

> On Oct 10, 2026, at 17:58, Mike Rapoport <rppt@xxxxxxxxxx> wrote:
> 
> On Sat, Oct 10, 2026 at 05:32:59PM +0800, Muchun Song wrote:
>> 
>> 
>>> On Oct 10, 2026, at 15:57, Muchun Song <songmuchun@xxxxxxxxxxxxx> wrote:
>>> 
>>> For vmemmap-optimized sections, tail struct pages may be backed by
>>> shared vmemmap pages. Those shared pages must carry the same page zone
>>> ID as the struct pages initialized for the section.
>>> 
>>> Warn in __init_single_page() if the shared tail page has a different
>>> page_zone_id(), which would indicate inconsistent initialization.
>> 
>> Please ignore Sashiko's report [1], both are false positive. It didn't
>> realize that shared vmemmap pages are initialized early before __init_single_page().
> 
> I didn't realize it too when I read this first :)
> 
> How about a short comment above vmemmap_optimization_verify_zone()?

Good point. A short comment there would be helpful.

Thanks,
Muchun

> 
>> [1] https://sashiko.dev/#/patchset/20261010075755.83339-1-songmuchun%40bytedance.com?part=6
>> 
>> Thanks.
> 
> -- 
> Sincerely yours,
> Mike.