Re: [PATCH v2 RESEND] mm/sparsemem: pfn_to_page is not valid yet on SPARSEMEM

[Dan Williams]

On Tue, Feb 18, 2020 at 7:05 PM Baoquan He <bhe@xxxxxxxxxx> wrote:
>
> From: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
>
> When we use SPARSEMEM instead of SPARSEMEM_VMEMMAP, pfn_to_page()
> doesn't work before sparse_init_one_section() is called. This leads to a
> crash when hotplug memory:

I'd also add:

"On x86 the impact is limited to x86_32 builds, or x86_64
configurations that override the default setting for
SPARSEMEM_VMEMMAP".

Other than that:

Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx>