Re: [PATCH v2] mm/memory_hotplug: prevent accessing by index=-1

[David Hildenbrand]

On 06.06.24 10:06, Anastasia Belova wrote:
> 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@xxxxxxxxxxxxx>
> ---
>   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 431b1f6753c0..db78d1b725fc 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -846,7 +846,6 @@ 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;
>   
> @@ -857,6 +856,8 @@ 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);

Acked-by: David Hildenbrand <david@xxxxxxxxxx>

Thanks!

--
Cheers,

David / dhildenb