On Tue, 17 Sep 2019 23:40:08 +0800, xiangxia.m....@gmail.com wrote:
> From: Tonghao Zhang <xiangxia.m....@gmail.com>
>
> If we register a net device which name is not valid
> (dev_get_valid_name), register_netdevice will return err
> codes and will not run dev->priv_destructor. The memory
> will leak. This patch adds check in ovs_vport_free and
> set the vport NULL.
>
> Fixes: 309b66970ee2 ("net: openvswitch: do not free vport if
> register_netdevice() is failed.")
> Cc: Taehee Yoo <ap420...@gmail.com>
> Signed-off-by: Tonghao Zhang <xiangxia.m....@gmail.com>
Thanks for the patch, I see what you're trying to do, but..
> diff --git a/net/openvswitch/vport-internal_dev.c
> b/net/openvswitch/vport-internal_dev.c
> index d2437b5..074c43f 100644
> --- a/net/openvswitch/vport-internal_dev.c
> +++ b/net/openvswitch/vport-internal_dev.c
> @@ -159,7 +159,6 @@ static struct vport *internal_dev_create(const struct
> vport_parms *parms)
> struct internal_dev *internal_dev;
> struct net_device *dev;
> int err;
> - bool free_vport = true;
>
> vport = ovs_vport_alloc(0, &ovs_internal_vport_ops, parms);
> if (IS_ERR(vport)) {
> @@ -190,10 +189,8 @@ static struct vport *internal_dev_create(const struct
> vport_parms *parms)
>
> rtnl_lock();
> err = register_netdevice(vport->dev);
> - if (err) {
> - free_vport = false;
> + if (err)
> goto error_unlock;
> - }
>
> dev_set_promiscuity(vport->dev, 1);
> rtnl_unlock();
> @@ -207,8 +204,7 @@ static struct vport *internal_dev_create(const struct
> vport_parms *parms)
> error_free_netdev:
> free_netdev(dev);
> error_free_vport:
> - if (free_vport)
> - ovs_vport_free(vport);
> + ovs_vport_free(vport);
> error:
> return ERR_PTR(err);
> }
> diff --git a/net/openvswitch/vport.c b/net/openvswitch/vport.c
> index 3fc38d1..281259a 100644
> --- a/net/openvswitch/vport.c
> +++ b/net/openvswitch/vport.c
> @@ -157,11 +157,20 @@ struct vport *ovs_vport_alloc(int priv_size, const
> struct vport_ops *ops,
> */
> void ovs_vport_free(struct vport *vport)
> {
> + /* We should check whether vport is NULL.
> + * We may free it again, for example in internal_dev_create
> + * if register_netdevice fails, vport may have been freed via
> + * internal_dev_destructor.
> + */
> + if (unlikely(!vport))
> + return;
> +
> /* vport is freed from RCU callback or error path, Therefore
> * it is safe to use raw dereference.
> */
> kfree(rcu_dereference_raw(vport->upcall_portids));
> kfree(vport);
> + vport = NULL;
vport here is a function argument, seems like setting it to NULL
right before the function ends will do nothing. Should we rather
set internal_dev->vport to NULL somehow?
Perhaps someone more familiar with OvS can chime in and review..
> }
> EXPORT_SYMBOL_GPL(ovs_vport_free);
>
