Re: [PATCH] net/mlx5e: Add missing check for xa_load

[Paolo Abeni]

On Mon, 2023-09-04 at 08:12 +0000, Chen Ni wrote:
> Add check for xa_load() in order to avoid NULL pointer
> dereference.
> 
> Fixes: b7c9400cbc48 ("net/mlx5e: Implement MACsec Rx data path using MACsec skb_metadata_dst")
> Signed-off-by: Chen Ni <nichen@xxxxxxxxxxx>
> ---
>  .../net/ethernet/mellanox/mlx5/core/en_accel/macsec.c  | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/macsec.c b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/macsec.c
> index c9c1db971652..d2467c0bc3c8 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/macsec.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/macsec.c
> @@ -1673,10 +1673,12 @@ void mlx5e_macsec_offload_handle_rx_skb(struct net_device *netdev,
>  
>  	rcu_read_lock();
>  	sc_xarray_element = xa_load(&macsec->sc_xarray, fs_id);
> -	rx_sc = sc_xarray_element->rx_sc;
> -	if (rx_sc) {
> -		dst_hold(&rx_sc->md_dst->dst);
> -		skb_dst_set(skb, &rx_sc->md_dst->dst);
> +	if (sc_xarray_element) {
> +		rx_sc = sc_xarray_element->rx_sc;
> +		if (rx_sc) {
> +			dst_hold(&rx_sc->md_dst->dst);
> +			skb_dst_set(skb, &rx_sc->md_dst->dst);
> +		}
>  	}
>  
>  	rcu_read_unlock();

@Saeed: I assume this will first go through your tree and then we will
get back via a later PR, right?

In any case Pavan's comment looks reasonable to me, @Chen: please
address it.

Cheers,

Paolo