[lvc-project] [PATCH 6.1] mm/memory_hotplug: prevent accessing by index=-1

[Mikhail Lobanov]

From: Anastasia Belova <abelova at astralinux.ru>

commit 5958d35917e1296f46dfc8b8c959732efd6d8d5d upstream.

nid may be equal to NUMA_NO_NODE=-1.  Prevent accessing node_data array by
invalid index with check for nid.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: e83a437faa62 ("mm/memory_hotplug: introduce "auto-movable" online policy")
Signed-off-by: Anastasia Belova <abelova at astralinux.ru>
Acked-by: David Hildenbrand <david at redhat.com>
Acked-by: Oscar Salvador <osalvador at suse.de>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
Signed-off-by: Mikhail Lobanov <m.lobanov at rosalinux.ru>
---
 mm/memory_hotplug.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index dc17618bad8b..90f0cc9a298a 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -783,7 +783,6 @@ static bool auto_movable_can_online_movable(int nid, struct memory_group *group,
 	unsigned long kernel_early_pages, movable_pages;
 	struct auto_movable_group_stats group_stats = {};
 	struct auto_movable_stats stats = {};
-	pg_data_t *pgdat = NODE_DATA(nid);
 	struct zone *zone;
 	int i;
 
@@ -794,6 +793,8 @@ static bool auto_movable_can_online_movable(int nid, struct memory_group *group,
 			auto_movable_stats_account_zone(&stats, zone);
 	} else {
 		for (i = 0; i < MAX_NR_ZONES; i++) {
+			pg_data_t *pgdat = NODE_DATA(nid);
+
 			zone = pgdat->node_zones + i;
 			if (populated_zone(zone))
 				auto_movable_stats_account_zone(&stats, zone);
-- 
2.43.0