HI all,
I think there is a bug in function move_freepages_block.
981 int move_freepages_block(struct zone *zone, struct page *page,
...
987 start_pfn = page_to_pfn(page);
988 start_pfn = start_pfn & ~(pageblock_nr_pages-1);
989 start_page = pfn_to_page(start_pfn);
990 end_page = start_page + pageblock_nr_pages - 1;
991 end_pfn = start_pfn + pageblock_nr_pages - 1;
992
993 /* Do not cross zone boundaries */
994 if (!zone_spans_pfn(zone, start_pfn))
995 start_page = page;
The line 988 will align start_pfn with pageblock_nr_pages,
thus after line988, start_pfn maybe less than zone->pageblock_nr_pages,
in the worst case, start_pfn maybe outof the range of zone->node pfn.
and becomes a invalid pfn.
in this case, line 989 will be wrong.
so I think the check for start_pfn should be done before line 989, just like:
start_pfn = start_pfn & ~(pageblock_nr_pages-1); <== line 988
if (!zone_spans_pfn(zone, start_pfn))
start_pfn = page_to_pfn(page);
Regards,
Martin