net/mlx5: fix xstats reset reinitialization

  The mlx5_xstats_reset clears the device extended statistics.
In this function the driver may reinitialize the structures
that are used to read device counters.

In case of reinitialization, the number of counters may
change, which wouldn't be taken into account by the
reset API callback and can cause a segmentation fault.

This issue is fixed by allocating the counters size after
the reinitialization.

Fixes: a4193ae3bc4f ("net/mlx5: support extended statistics")
Cc: stable@dpdk.org

Signed-off-by: Shiri Kuzin <shirik@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>
---
 drivers/net/mlx5/mlx5_stats.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)
  

> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of Shiri Kuzin
> Sent: Monday, October 19, 2020 9:37 AM
> To: dev@dpdk.org
> Cc: matan@mellanox.com; rasland@mellanox.com;
> viacheslavo@mellanox.com; stable@dpdk.org
> Subject: [dpdk-dev] [PATCH] net/mlx5: fix xstats reset reinitialization
> 
> The mlx5_xstats_reset clears the device extended statistics.
> In this function the driver may reinitialize the structures that are used to read
> device counters.
> 
> In case of reinitialization, the number of counters may change, which
> wouldn't be taken into account by the reset API callback and can cause a
> segmentation fault.
> 
> This issue is fixed by allocating the counters size after the reinitialization.
> 
> Fixes: a4193ae3bc4f ("net/mlx5: support extended statistics")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Shiri Kuzin <shirik@nvidia.com>
> Acked-by: Matan Azrad <matan@nvidia.com>
Reported-by: Ralf Hoffmann <ralf.hoffmann@allegro-packets.com>
> ---
>  drivers/net/mlx5/mlx5_stats.c | 18 +++++++++++++++---
>  1 file changed, 15 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/mlx5/mlx5_stats.c b/drivers/net/mlx5/mlx5_stats.c
> index e30542e..82d4d4a 100644
> --- a/drivers/net/mlx5/mlx5_stats.c
> +++ b/drivers/net/mlx5/mlx5_stats.c
> @@ -17,6 +17,7 @@
>  #include "mlx5_defs.h"
>  #include "mlx5.h"
>  #include "mlx5_rxtx.h"
> +#include "mlx5_malloc.h"
> 
>  /**
>   * DPDK callback to get extended device statistics.
> @@ -216,8 +217,7 @@
>  	struct mlx5_xstats_ctrl *xstats_ctrl = &priv->xstats_ctrl;
>  	int stats_n;
>  	unsigned int i;
> -	unsigned int n = xstats_ctrl->mlx5_stats_n;
> -	uint64_t counters[n];
> +	uint64_t *counters;
>  	int ret;
> 
>  	stats_n = mlx5_os_get_stats_n(dev);
> @@ -228,17 +228,29 @@
>  	}
>  	if (xstats_ctrl->stats_n != stats_n)
>  		mlx5_os_stats_init(dev);
> +	counters =  mlx5_malloc(MLX5_MEM_SYS, sizeof(*counters) *
> +			xstats_ctrl->mlx5_stats_n, 0,
> +			SOCKET_ID_ANY);
> +	if (!counters) {
> +		DRV_LOG(WARNING, "port %u unable to allocate memory
> for xstats "
> +				"counters",
> +		     dev->data->port_id);
> +		rte_errno = ENOMEM;
> +		return -rte_errno;
> +	}
>  	ret = mlx5_os_read_dev_counters(dev, counters);
>  	if (ret) {
>  		DRV_LOG(ERR, "port %u cannot read device counters: %s",
>  			dev->data->port_id, strerror(rte_errno));
> +		mlx5_free(counters);
>  		return ret;
>  	}
> -	for (i = 0; i != n; ++i) {
> +	for (i = 0; i != xstats_ctrl->mlx5_stats_n; ++i) {
>  		xstats_ctrl->base[i] = counters[i];
>  		xstats_ctrl->hw_stats[i] = 0;
>  	}
>  	mlx5_txpp_xstats_reset(dev);
> +	mlx5_free(counters);
>  	return 0;
>  }
> 
> --
> 1.8.3.1
  

Hi,

> -----Original Message-----
> From: Shiri Kuzin <shirik@nvidia.com>
> Sent: Monday, October 19, 2020 9:37 AM
> To: dev@dpdk.org
> Cc: matan@mellanox.com; rasland@mellanox.com;
> viacheslavo@mellanox.com; stable@dpdk.org
> Subject: [PATCH] net/mlx5: fix xstats reset reinitialization
> 
> The mlx5_xstats_reset clears the device extended statistics.
> In this function the driver may reinitialize the structures
> that are used to read device counters.
> 
> In case of reinitialization, the number of counters may
> change, which wouldn't be taken into account by the
> reset API callback and can cause a segmentation fault.
> 
> This issue is fixed by allocating the counters size after
> the reinitialization.
> 
> Fixes: a4193ae3bc4f ("net/mlx5: support extended statistics")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Shiri Kuzin <shirik@nvidia.com>
> Acked-by: Matan Azrad <matan@nvidia.com>
> ---
>  drivers/net/mlx5/mlx5_stats.c | 18 +++++++++++++++---
>  1 file changed, 15 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/mlx5/mlx5_stats.c b/drivers/net/mlx5/mlx5_stats.c
> index e30542e..82d4d4a 100644
> --- a/drivers/net/mlx5/mlx5_stats.c
> +++ b/drivers/net/mlx5/mlx5_stats.c
> @@ -17,6 +17,7 @@
>  #include "mlx5_defs.h"
>  #include "mlx5.h"
>  #include "mlx5_rxtx.h"
> +#include "mlx5_malloc.h"
> 
>  /**
>   * DPDK callback to get extended device statistics.
> @@ -216,8 +217,7 @@
>  	struct mlx5_xstats_ctrl *xstats_ctrl = &priv->xstats_ctrl;
>  	int stats_n;
>  	unsigned int i;
> -	unsigned int n = xstats_ctrl->mlx5_stats_n;
> -	uint64_t counters[n];
> +	uint64_t *counters;
>  	int ret;
> 
>  	stats_n = mlx5_os_get_stats_n(dev);
> @@ -228,17 +228,29 @@
>  	}
>  	if (xstats_ctrl->stats_n != stats_n)
>  		mlx5_os_stats_init(dev);
> +	counters =  mlx5_malloc(MLX5_MEM_SYS, sizeof(*counters) *
> +			xstats_ctrl->mlx5_stats_n, 0,
> +			SOCKET_ID_ANY);
> +	if (!counters) {
> +		DRV_LOG(WARNING, "port %u unable to allocate memory
> for xstats "
> +				"counters",
> +		     dev->data->port_id);
> +		rte_errno = ENOMEM;
> +		return -rte_errno;
> +	}
>  	ret = mlx5_os_read_dev_counters(dev, counters);
>  	if (ret) {
>  		DRV_LOG(ERR, "port %u cannot read device counters: %s",
>  			dev->data->port_id, strerror(rte_errno));
> +		mlx5_free(counters);
>  		return ret;
>  	}
> -	for (i = 0; i != n; ++i) {
> +	for (i = 0; i != xstats_ctrl->mlx5_stats_n; ++i) {
>  		xstats_ctrl->base[i] = counters[i];
>  		xstats_ctrl->hw_stats[i] = 0;
>  	}
>  	mlx5_txpp_xstats_reset(dev);
> +	mlx5_free(counters);
>  	return 0;
>  }
> 
> --
> 1.8.3.1

Patch applied to next-net-mlx,

Kindest regards,
Raslan Darawsheh