On Mon, Jun 28, 2021 at 05:11:05PM +0800, zhanglianjie wrote:

The cause of the problem is as follows:
1. when cat /sys/devices/system/memory/memory0/valid_zones,
   test_pages_in_a_zone() will be called.
2. test_pages_in_a_zone() finds the zone according to stat_pfn = 0.
   The smallest pfn of the numa node in the mips architecture is 128,
   and the page corresponding to the previous 0~127 pfn is not
   initialized (page->flags is 0xFFFFFFFF)
3. The nid and zonenum obtained using page_zone(pfn_to_page(0)) are out
   of bounds in the corresponding array,
   &NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)],
   access to the out-of-bounds zone member variables appear abnormal,
   resulting in Oops.
Therefore, it is necessary to keep the page between 0 and the minimum
pfn to prevent Oops from appearing.

Signed-off-by: zhanglianjie <redacted>
---
 arch/mips/loongson64/numa.c | 3 +++
 1 file changed, 3 insertions(+)

applied to mips-next (with subject changed to reflect what patch does).

Thomas.

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