From: David Ahern <dsa@cumulusnetworks•com>
To: Nikolay Aleksandrov <nikolay@cumulusnetworks•com>,
netdev@vger•kernel.org
Cc: shm@cumulusnetworks•com, roopa@cumulusnetworks•com,
gospo@cumulusnetworks•com, jtoppins@cumulusnetworks•com,
ddutt@cumulusnetworks•com, hannes@stressinduktion•org,
nicolas.dichtel@6wind•com, stephen@networkplumber•org,
hadi@mojatatu•com, ebiederm@xmission•com, davem@davemloft•net
Subject: Re: [RFC net-next 3/6] net: Introduce VRF device driver - v2
Date: Mon, 06 Jul 2015 10:46:59 -0600 [thread overview]
Message-ID: <559AB103.1070603@cumulusnetworks.com> (raw)
In-Reply-To: <559AAEE1.2050105@cumulusnetworks.com>
On 7/6/15 10:37 AM, Nikolay Aleksandrov wrote:
>> +static int vrf_add_slave(struct net_device *dev,
>> + struct net_device *port_dev)
>> +{
>> + if (!dev || !port_dev || dev_net(dev) != dev_net(port_dev))
>> + return -ENODEV;
>> +
>> + if (!vrf_is_master(port_dev) && !vrf_is_slave(port_dev)) {
>> + struct slave *s = kzalloc(sizeof(*s), GFP_KERNEL);
>> + struct net_vrf *vrf = netdev_priv(dev);
>> + struct slave_queue *queue = &vrf->queue;
>> + bool is_running = netif_running(port_dev);
>> + unsigned int flags = port_dev->flags;
>> + int ret;
>> +
>> + if (!s)
>> + return -ENOMEM;
>> +
>> + s->dev = port_dev;
>> +
>> + spin_lock_bh(&queue->lock);
>> + __vrf_insert_slave(queue, s, dev);
>> + spin_unlock_bh(&queue->lock);
>> +
>> + port_dev->vrf_ptr = kmalloc(sizeof(*port_dev->vrf_ptr),
>> + GFP_KERNEL);
>> + if (!port_dev->vrf_ptr)
>> + return -ENOMEM;
> ^^^^^^^^^
> I believe you'll have a slave in the list with inconsistent state which could
> even lead to null ptr derefernce if vrf_ptr is used, also __vrf_insert_slave
> does dev_hold so the dev refcnt will be incorrect as well.
Right. Good catch, will fix.
>
>> +
>> + port_dev->vrf_ptr->ifindex = dev->ifindex;
>> + port_dev->vrf_ptr->tb_id = vrf->tb_id;
>> +
>> + /* register the packet handler for slave ports */
>> + ret = netdev_rx_handler_register(port_dev, vrf_handle_frame,
>> + (void *)dev);
>> + if (ret) {
>> + netdev_err(port_dev,
>> + "Device %s failed to register rx_handler\n",
>> + port_dev->name);
>> + kfree(port_dev->vrf_ptr);
>> + kfree(s);
>> + return ret;
> ^^^^^^^^^^
> The slave is being freed while on the list here, device's refcnt will be wrong etc.
ack. Will fix.
>
>> + }
>> +
>> + if (is_running) {
>> + ret = dev_change_flags(port_dev, flags & ~IFF_UP);
>> + if (ret < 0)
>> + goto out_fail;
>> + }
>> +
>> + ret = netdev_master_upper_dev_link(port_dev, dev);
>> + if (ret < 0)
>> + goto out_fail;
>> +
>> + if (is_running) {
>> + ret = dev_change_flags(port_dev, flags);
>> + if (ret < 0)
>> + goto out_fail;
>> + }
>> +
>> + port_dev->flags |= IFF_SLAVE;
>> +
>> + return 0;
>> +
>> +out_fail:
>> + spin_lock_bh(&queue->lock);
>> + __vrf_kill_slave(queue, s);
>> + spin_unlock_bh(&queue->lock);
>
> __vrf_kill_slave() doesn't do upper device unlink and the device can be linked
> if we fail in the dev_change_flags above.
will fix.
>
>> +
>> + return ret;
>> + }
>> +
>> + return -EINVAL;
>> +}
> ^^^^
> In my opinion the structure of the above function should change to something more
> straightforward with proper exit labels and cleanup upon failure, also a level of
> indentation can be avoided.
Sure. The indentation comes after the pointer checks so locals can be
intialized when declared. Will work on the clean up/simplification for
next rev.
>
>> +
>> +static int vrf_del_slave(struct net_device *dev,
>> + struct net_device *port_dev)
>> +{
>> + struct net_vrf *vrf = netdev_priv(dev);
>> + struct slave_queue *queue = &vrf->queue;
>> + struct slave *slave = __vrf_find_slave_dev(queue, port_dev);
>> + bool is_running = netif_running(port_dev);
>> + unsigned int flags = port_dev->flags;
>> + int ret = 0;
>
> ret seems unused/unchecked in this function
It is used but not checked. I struggled with what to do on the error
path. Do we want netdev_err() on a failure?
>
>> +
>> + if (!slave)
>> + return -EINVAL;
>> +
>> + if (is_running)
>> + ret = dev_change_flags(port_dev, flags & ~IFF_UP);
>> +
>> + spin_lock_bh(&queue->lock);
>> + __vrf_kill_slave(queue, slave);
>> + spin_unlock_bh(&queue->lock);
>> +
>> + netdev_upper_dev_unlink(port_dev, dev);
>> +
>> + if (is_running)
>> + ret = dev_change_flags(port_dev, flags);
>> +
>> + return 0;
>> +}
>> +
>> +static int vrf_dev_init(struct net_device *dev)
>> +{
>> + struct net_vrf *vrf = netdev_priv(dev);
>> +
>> + spin_lock_init(&vrf->queue.lock);
>> + INIT_LIST_HEAD(&vrf->queue.all_slaves);
>> + vrf->queue.master_dev = dev;
>> +
>> + dev->dstats = netdev_alloc_pcpu_stats(struct pcpu_dstats);
>> + dev->flags = IFF_MASTER | IFF_NOARP;
>> + if (!dev->dstats)
>> + return -ENOMEM;
> ^^^^^
> nit: I'd suggest moving the check after the allocation
agreed.
David
next prev parent reply other threads:[~2015-07-06 16:47 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-06 15:03 [RFC net-next 0/6] Proposal for VRF-lite - v2 David Ahern
2015-07-06 15:03 ` [RFC net-next 1/6] fib: export symbols David Ahern
2015-07-06 15:03 ` [RFC net-next 2/6] net: Preparation for vrf device David Ahern
2015-07-08 8:37 ` Nicolas Dichtel
2015-07-08 8:40 ` Nicolas Dichtel
2015-07-08 16:10 ` David Ahern
2015-07-06 15:03 ` [RFC net-next 3/6] net: Introduce VRF device driver - v2 David Ahern
2015-07-06 15:42 ` Nicolas Dichtel
2015-07-06 16:37 ` Nikolay Aleksandrov
2015-07-06 16:46 ` David Ahern [this message]
2015-07-08 9:27 ` Nicolas Dichtel
2015-07-08 16:38 ` David Ahern
2015-07-08 18:34 ` Sowmini Varadhan
2015-07-09 17:19 ` David Ahern
2015-07-09 17:28 ` Sowmini Varadhan
2015-07-10 1:36 ` Eric W. Biederman
2015-07-10 2:12 ` David Ahern
2015-07-10 3:55 ` Eric W. Biederman
2015-07-10 4:20 ` David Ahern
2015-07-10 4:56 ` Eric W. Biederman
2015-07-10 18:42 ` David Ahern
2015-07-10 2:39 ` David Ahern
2015-07-10 3:28 ` Sowmini Varadhan
2015-07-10 3:44 ` David Ahern
2015-07-06 15:03 ` [RFC net-next 4/6] net: Modifications to ipv4 stack for VRF devices David Ahern
2015-07-06 15:03 ` [RFC net-next 5/6] net: Add sk_bind_dev_if to task_struct David Ahern
2015-07-06 15:03 ` [RFC net-next 6/6] net: Add chvrf command David Ahern
2015-07-06 15:03 ` [RFC PATCH] iproute2: Add support for VRF device David Ahern
2015-07-06 15:40 ` [RFC net-next 0/6] Proposal for VRF-lite - v2 Nicolas Dichtel
2015-07-06 17:53 ` Shrijeet Mukherjee
2015-07-08 9:30 ` Nicolas Dichtel
2015-07-10 5:14 ` Scott Feldman
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