The size of struct per_cpu_zonestat can be 0 on !SMP && !NUMA. In that
case, zone->per_cpu_zonestats will always equal to boot_zonestats. But
in zone_pcp_reset(), zone->per_cpu_zonestats is freed via free_percpu()
directly without checking against boot_zonestats first. boot_zonestats
will be released by free_percpu() unexpectedly.
Fixes: 28f836b6777b ("mm/page_alloc: split per cpu page lists and zone stats")
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>
---
mm/page_alloc.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 27ef763bb59f..cad235770948 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -9505,9 +9505,11 @@ void zone_pcp_reset(struct zone *zone)
drain_zonestat(zone, pzstats);
}
free_percpu(zone->per_cpu_pageset);
- free_percpu(zone->per_cpu_zonestats);
zone->per_cpu_pageset = &boot_pageset;
- zone->per_cpu_zonestats = &boot_zonestats;
+ if (zone->per_cpu_zonestats != &boot_zonestats) {
+ free_percpu(zone->per_cpu_zonestats);
+ zone->per_cpu_zonestats = &boot_zonestats;
+ }
}
}
--
2.23.0
