Re: [PATCH v5 1/3] vdpa: Fix error logic in vdpa_nl_cmd_dev_get_doit

[Si-Wei Liu <si-wei.liu@oracle.com>]

On 5/10/2022 4:27 AM, Eli Cohen wrote:
> In vdpa_nl_cmd_dev_get_doit(), if the call to genlmsg_reply() fails we
> must not call nlmsg_free() since this is done inside genlmsg_reply().
>
> Fix it.
>
> Fixes: bc0d90ee021f ("vdpa: Enable user to query vdpa device info")
> Acked-by: Jason Wang <jasowang@redhat.com>
> Signed-off-by: Eli Cohen <elic@nvidia.com>
Reviewed-by: Si-Wei Liu <si-wei.liu@oracle.com>
> ---
>   drivers/vdpa/vdpa.c | 13 +++++++++----
>   1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
> index 2b75c00b1005..fac89a0d8178 100644
> --- a/drivers/vdpa/vdpa.c
> +++ b/drivers/vdpa/vdpa.c
> @@ -756,14 +756,19 @@ static int vdpa_nl_cmd_dev_get_doit(struct sk_buff *skb, struct genl_info *info)
>   		goto mdev_err;
>   	}
>   	err = vdpa_dev_fill(vdev, msg, info->snd_portid, info->snd_seq, 0, info->extack);
> -	if (!err)
> -		err = genlmsg_reply(msg, info);
> +	if (err)
> +		goto mdev_err;
> +
> +	err = genlmsg_reply(msg, info);
> +	put_device(dev);
> +	mutex_unlock(&vdpa_dev_mutex);
> +	return err;
> +
>   mdev_err:
>   	put_device(dev);
>   err:
>   	mutex_unlock(&vdpa_dev_mutex);
> -	if (err)
> -		nlmsg_free(msg);
> +	nlmsg_free(msg);
>   	return err;
>   }
>