Re: [PATCH v1] mnt_idmapping: Use kmemdup_array instead of kmemdup for multiple allocation

[Christian Brauner]

On Wed, Aug 21, 2024 at 05:15:07PM GMT, Yu Jiaoliang wrote:
> Let the kememdup_array() take care about multiplication and possible
> overflows.
> 
> Signed-off-by: Yu Jiaoliang <yujiaoliang@xxxxxxxx>
> ---
>  fs/mnt_idmapping.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/mnt_idmapping.c b/fs/mnt_idmapping.c
> index 3c60f1eaca61..fea0244a87ce 100644
> --- a/fs/mnt_idmapping.c
> +++ b/fs/mnt_idmapping.c
> @@ -228,9 +228,9 @@ static int copy_mnt_idmap(struct uid_gid_map *map_from,
>  		return 0;
>  	}
>  
> -	forward = kmemdup(map_from->forward,
> -			  nr_extents * sizeof(struct uid_gid_extent),
> -			  GFP_KERNEL_ACCOUNT);
> +	forward = kmemdup_array(map_from->forward, nr_extents,
> +				sizeof(struct uid_gid_extent),
> +				GFP_KERNEL_ACCOUNT);

Why did you only convert the forward array and not the reverse array?