Re: [PATCH 2/3] net/virtio: fix crash when close virtio dev twice

[Yuanhan Liu <yuanhan.liu@linux.intel.com>]

On Mon, Feb 20, 2017 at 10:04:46PM +0800, hanxueluo@126.com wrote:
> From: Huanle Han <hanxueluo@gmail.com>
> 
> This commit fixs segment fault when rte_eth_dev_close()
> is called on a virtio dev more than once.
> Assigning zero after free to avoids freed memory to
> be accessed again.

Thanks for the fix! And here are few more minor nits you might want be
awre of:

- a fix patch needs a fixline (check http://dpdk.org/dev for howto just
  in case you don't know)

- if it fixes a fatal bug (like this one), it should also be picked (or
  backported) to a specific stable release. In this case, you should add
     Cc: stable@dpdk.org

  just before your SoB (Signed-off-by).

	--yliu
> 
> Signed-off-by: Huanle Han <hanxueluo@gmail.com>
> ---
>  drivers/net/virtio/virtio_ethdev.c | 5 +++++
>  lib/librte_ether/rte_ethdev.c      | 2 ++
>  2 files changed, 7 insertions(+)
> 
> diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
> index 8465e1a..b9565db 100644
> --- a/drivers/net/virtio/virtio_ethdev.c
> +++ b/drivers/net/virtio/virtio_ethdev.c
> @@ -545,6 +545,9 @@ virtio_free_queues(struct virtio_hw *hw)
>  	int queue_type;
>  	uint16_t i;
>  
> +	if (hw->vqs == NULL)
> +		return;
> +
>  	for (i = 0; i < nr_vq; i++) {
>  		vq = hw->vqs[i];
>  		if (!vq)
> @@ -563,9 +566,11 @@ virtio_free_queues(struct virtio_hw *hw)
>  		}
>  
>  		rte_free(vq);
> +		hw->vqs[i] = NULL;
>  	}
>  
>  	rte_free(hw->vqs);
> +	hw->vqs = NULL;
>  }
>  
>  static int
> diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
> index eb0a94a..24f82dc 100644
> --- a/lib/librte_ether/rte_ethdev.c
> +++ b/lib/librte_ether/rte_ethdev.c
> @@ -1074,8 +1074,10 @@ rte_eth_dev_close(uint8_t port_id)
>  	dev->data->dev_started = 0;
>  	(*dev->dev_ops->dev_close)(dev);
>  
> +	dev->data->nb_rx_queues = 0;
>  	rte_free(dev->data->rx_queues);
>  	dev->data->rx_queues = NULL;
> +	dev->data->nb_tx_queues = 0;
>  	rte_free(dev->data->tx_queues);
>  	dev->data->tx_queues = NULL;
>  }
> -- 
> 2.7.4
>