Re: [PATCH] net: ethernet/mellanox: fix dereference before null check

[Greg KH <gregkh@linuxfoundation.org>]

On Fri, Sep 30, 2022 at 05:13:35PM +0530, Praghadeesh T K S wrote:
> net: ethernet/mellanox: fix dereference before null check
> macsec dereferenced before null check
> bug identified by coverity's linux-next weekly scan
> Coverity CID No: 1525317
> 
> Signed-off-by: Praghadeesh T K S <praghadeeshthevendria@gmail.com>
> ---
>  drivers/net/ethernet/mellanox/mlx5/core/en_accel/macsec.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> 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 5da746d..e822c2a 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/macsec.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/macsec.c
> @@ -1846,11 +1846,11 @@ int mlx5e_macsec_init(struct mlx5e_priv *priv)
>  void mlx5e_macsec_cleanup(struct mlx5e_priv *priv)
>  {
>  	struct mlx5e_macsec *macsec = priv->macsec;
> -	struct mlx5_core_dev *mdev = macsec->mdev;
>  
>  	if (!macsec)
>  		return;
>  
> +	struct mlx5_core_dev *mdev = macsec->mdev;
>  	mlx5_notifier_unregister(mdev, &macsec->nb);
>  
>  	mlx5e_macsec_fs_cleanup(macsec->macsec_fs);

Always test-build your changes before you get a grumpy maintainer asking
why you didn't test-build your changes...

Also, the original code is just fine, Coverity is wrong here, don't you
think?  Look at the output of what the code is doing please...

thanks,

greg k-h