[PATCH] net/mlx5: fix destroying empty matchers list

[Tal Shnaiderman]

> Subject: [PATCH] net/mlx5: fix destroying empty matchers list
> 
> The table remove callback function is trying to destroy the matchers list
> associated with table entries without checking if the list is valid, which causes
> nullptr dereference.
> Fixed by validating the matchers list before destroying it.
> 
> Issue can be reproduced with testpmd on Windows, when you run:
> port close all
> 
> Fixes: 1872635570be ("net/mlx5: make matcher list thread safe")
> Cc: stable at dpdk.org
> 
> Signed-off-by: Adham Masarwah <adham at nvidia.com>
> Acked-by: Viacheslav Ovsiienko <viacheslavo at nvidia.com>
> ---
>  drivers/net/mlx5/mlx5_flow_dv.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/mlx5/mlx5_flow_dv.c
> b/drivers/net/mlx5/mlx5_flow_dv.c index ef9c66eddf..baef252a7a 100644
> --- a/drivers/net/mlx5/mlx5_flow_dv.c
> +++ b/drivers/net/mlx5/mlx5_flow_dv.c
> @@ -10503,7 +10503,8 @@ flow_dv_tbl_remove_cb(void *tool_ctx, struct
> mlx5_list_entry *entry)
>  			tbl_data->tunnel->tunnel_id : 0,
>  			tbl_data->group_id);
>  	}
> -	mlx5_list_destroy(tbl_data->matchers);
> +	if (tbl_data->matchers)
> +		mlx5_list_destroy(tbl_data->matchers);
>  	mlx5_ipool_free(sh->ipool[MLX5_IPOOL_JUMP], tbl_data->idx);  }
> 
> --
> 2.16.1.windows.4

Acked-by: Tal Shnaiderman <talshn at nvidia.com>