net/mlx5: fix the empty flow error structure

  The output flow error parameter is used to indicate the detailed
reason of the failure when calling a rte_flow_* interface. Even
though sometimes the application will not check it or use it, the PMD
must fill it in the failure branch before returning. Or else, some
dirty value in the stack, heap will be accessed as a pointer and then
cause a crash.
In this case, when a port is stopped, it is not allowed to insert a
flow from application. The detailed error information should be
filled. If the application needs to check the detailed error reason,
it will get the information but not result in any crash.

Fixes: 6ec024870715 ("net/mlx5: check device stat before creating flow")

Signed-off-by: Bing Zhao <bingz@mellanox.com>
Acked-by: Ori Kam <orika@mellanox.com>
---
 drivers/net/mlx5/mlx5_flow.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
  

Hi,

> -----Original Message-----
> From: Bing Zhao <bingz@mellanox.com>
> Sent: Friday, April 17, 2020 10:31 AM
> To: Ori Kam <orika@mellanox.com>; Slava Ovsiienko
> <viacheslavo@mellanox.com>; Raslan Darawsheh <rasland@mellanox.com>
> Cc: Matan Azrad <matan@mellanox.com>; dev@dpdk.org
> Subject: [PATCH] net/mlx5: fix the empty flow error structure
> 
> The output flow error parameter is used to indicate the detailed
> reason of the failure when calling a rte_flow_* interface. Even
> though sometimes the application will not check it or use it, the PMD
> must fill it in the failure branch before returning. Or else, some
> dirty value in the stack, heap will be accessed as a pointer and then
> cause a crash.
> In this case, when a port is stopped, it is not allowed to insert a
> flow from application. The detailed error information should be
> filled. If the application needs to check the detailed error reason,
> it will get the information but not result in any crash.
> 
> Fixes: 6ec024870715 ("net/mlx5: check device stat before creating flow")
Fixed Fixes line sha
> 
> Signed-off-by: Bing Zhao <bingz@mellanox.com>
> Acked-by: Ori Kam <orika@mellanox.com>
> ---
>  drivers/net/mlx5/mlx5_flow.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/mlx5/mlx5_flow.c b/drivers/net/mlx5/mlx5_flow.c
> index c529aa3..6a5522c 100644
> --- a/drivers/net/mlx5/mlx5_flow.c
> +++ b/drivers/net/mlx5/mlx5_flow.c
> @@ -4490,9 +4490,12 @@ struct rte_flow *
>  	 * are not affected.
>  	 */
>  	if (unlikely(!dev->data->dev_started)) {
> -		rte_errno = ENODEV;
>  		DRV_LOG(DEBUG, "port %u is not started when "
>  			"inserting a flow", dev->data->port_id);
> +		rte_flow_error_set(error, ENODEV,
> +				   RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
> +				   NULL,
> +				   "port not started");
>  		return NULL;
>  	}
>  	return (void *)(uintptr_t)flow_list_create(dev, &priv->flows,
> --
> 1.8.3.1

Patch applied to next-net-mlx,

Kindest regards,
Raslan Darawsheh