The __add_zone() maybe call sleep-able init_currently_empty_zone() to init wait_table, But this function also modifies the zone_start_pfn without any lock. It is bugy. So we move this modification out, and we ensure the modification of zone_start_pfn is only done with zone_span_writelock() held or in booting. Since zone_start_pfn is not modified by init_currently_empty_zone() grow_zone_span() needs to check zone_start_pfn before update it. CC: Mel Gorman <mel@xxxxxxxxx> Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxx> Reported-by: Yasuaki ISIMATU <isimatu.yasuaki@xxxxxxxxxxxxxx> Tested-by: Wen Congyang <wency@xxxxxxxxxxxxxx> --- mm/memory_hotplug.c | 2 +- mm/page_alloc.c | 3 +-- 2 files changed, 2 insertions(+), 3 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index b62d429b..790561f 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -205,7 +205,7 @@ static void grow_zone_span(struct zone *zone, unsigned long start_pfn, zone_span_writelock(zone); old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages; - if (start_pfn < zone->zone_start_pfn) + if (!zone->zone_start_pfn || start_pfn < zone->zone_start_pfn) zone->zone_start_pfn = start_pfn; zone->spanned_pages = max(old_zone_end_pfn, end_pfn) - diff --git a/mm/page_alloc.c b/mm/page_alloc.c index c13ea75..2545013 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3997,8 +3997,6 @@ int __meminit init_currently_empty_zone(struct zone *zone, return ret; pgdat->nr_zones = zone_idx(zone) + 1; - zone->zone_start_pfn = zone_start_pfn; - mminit_dprintk(MMINIT_TRACE, "memmap_init", "Initialising map node %d zone %lu pfns %lu -> %lu\n", pgdat->node_id, @@ -4465,6 +4463,7 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat, ret = init_currently_empty_zone(zone, zone_start_pfn, size, MEMMAP_EARLY); BUG_ON(ret); + zone->zone_start_pfn = zone_start_pfn; memmap_init(size, nid, j, zone_start_pfn); zone_start_pfn += size; } -- 1.7.4.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>