Arm64 crash while reading memory sysfs

[Catalin Marinas]

On Wed, May 26, 2021 at 12:09:14PM +0000, Qian Cai (QUIC) wrote:
> [    0.000000] Early memory node ranges
> [    0.000000]   node   0: [mem 0x0000000090000000-0x0000000091ffffff]

Maybe de-selecting HOLES_IN_ZONE is not correct for arm64 in all
circumstances. In a configuration with 64K pages, MAX_ORDER is 14,
MAX_ORDER_NR_PAGES is 8192, so a 2^29 address range. However, the above
range starts on 2^28 boundary.

SECTION_SIZE_BITS is 29 in this configuration but the corresponding
mem_map[] in the first half of the first section is probably not marked
as reserved as we'd do for NOMAP.

-- 
Catalin