Re: compaction: VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn))

[Mike Rapoport]

Hi,

On Thu, Apr 23, 2020 at 05:25:56PM -0400, Qian Cai wrote:
> Compaction starts to crash below on linux-next today. The faulty page belongs to Node 0 DMA32 zone.
> Iâll continue to narrow it down, but just want to give a headup in case someone could beat me to it.
> 
> Debug output from free_area_init_core()
> [    0.000000] KK start page = ffffea0000000040, end page = ffffea0000040000, nid = 0 DMA
> [    0.000000] KK start page = ffffea0000040000, end page = ffffea0004000000, nid = 0 DMA32
> [    0.000000] KK start page = ffffea0004000000, end page = ffffea0012000000, nid = 0 NORMAL
> [    0.000000] KK start page = ffffea0012000000, end page = ffffea0021fc0000, nid = 4 NORMAL
> 
> I donât understand how it could end up in such a situation. There are several recent patches look
> more related than some others.

Can you please add "mminit_loglevel=4 memblock=debug" to the kernel
command line?

> - mm: rework free_area_init*() funcitons
> https://lore.kernel.org/linux-mm/20200412194859.12663-1-rppt@xxxxxxxxxx/
> Could this somehow allow an invalid pfn to escape into the page allocator?
> Especially, is it related to skip the checks in memmap_init_zone()?
> https://lore.kernel.org/linux-mm/20200412194859.12663-16-rppt@xxxxxxxxxx


-- 
Sincerely yours,
Mike.