Re: [dpdk-dev] [PATCH 1/2] net/vhost: fix Vhost setup error path

[David Marchand <david.marchand@redhat.com>]

On Tue, Feb 18, 2020 at 3:35 PM Maxime Coquelin
<maxime.coquelin@redhat.com> wrote:
>
> If for some reason vhost_driver_setup() fails, the list
> element for the device may be freed without being removed
> from the internal list of devices.
>
> This patch fixes all the error paths, by unregistering the
> device from Vhost library it has been registered, remove
> the device from the list, reset device vring_state pointer
> from the global table and only free vring state if it had
> been allocated.
>
> Fixes: 3d01b759d267 ("net/vhost: delay driver setup")
>
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>  drivers/net/vhost/rte_eth_vhost.c | 21 ++++++++++++++-------
>  1 file changed, 14 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/net/vhost/rte_eth_vhost.c b/drivers/net/vhost/rte_eth_vhost.c
> index 90263ae77c..c0056bc8bf 100644
> --- a/drivers/net/vhost/rte_eth_vhost.c
> +++ b/drivers/net/vhost/rte_eth_vhost.c
> @@ -878,12 +878,12 @@ vhost_driver_setup(struct rte_eth_dev *eth_dev)
>
>         list = rte_zmalloc_socket(name, sizeof(*list), 0, numa_node);
>         if (list == NULL)
> -               goto error;
> +               return -1;
>
>         vring_state = rte_zmalloc_socket(name, sizeof(*vring_state),
>                                          0, numa_node);
>         if (vring_state == NULL)
> -               goto error;
> +               goto free_list;
>
>         list->eth_dev = eth_dev;
>         pthread_mutex_lock(&internal_list_lock);
> @@ -894,30 +894,37 @@ vhost_driver_setup(struct rte_eth_dev *eth_dev)
>         vring_states[eth_dev->data->port_id] = vring_state;
>
>         if (rte_vhost_driver_register(internal->iface_name, internal->flags))
> -               goto error;
> +               goto list_remove;
>
>         if (internal->disable_flags) {
>                 if (rte_vhost_driver_disable_features(internal->iface_name,
>                                                       internal->disable_flags))
> -                       goto error;
> +                       goto drv_unreg;
>         }
>
>         if (rte_vhost_driver_callback_register(internal->iface_name,
>                                                &vhost_ops) < 0) {
>                 VHOST_LOG(ERR, "Can't register callbacks\n");
> -               goto error;
> +               goto drv_unreg;
>         }
>
>         if (rte_vhost_driver_start(internal->iface_name) < 0) {
>                 VHOST_LOG(ERR, "Failed to start driver for %s\n",
>                           internal->iface_name);
> -               goto error;
> +               goto drv_unreg;
>         }
>
>         return 0;
>
> -error:
> +drv_unreg:
> +       rte_vhost_driver_unregister(internal->iface_name);
> +list_remove:
> +       pthread_mutex_lock(&internal_list_lock);
> +       TAILQ_REMOVE(&internal_list, list, next);
> +       pthread_mutex_unlock(&internal_list_lock);
> +       vring_states[eth_dev->data->port_id] = NULL;

We allocate/store in vring_states after inserting list in &internal_list.
Probably nitpicking but I would expect the opposite order on cleanup.


>         rte_free(vring_state);
> +free_list:
>         rte_free(list);
>
>         return -1;
> --
> 2.24.1
>

In any case,
Reviewed-by: David Marchand <david.marchand@redhat.com>



--
David Marchand