On 10/23/2023 5:52 PM, Alexandru Matei wrote:
> On 10/23/2023 5:29 PM, Stefano Garzarella wrote:
>> On Mon, Oct 23, 2023 at 05:08:33PM +0300, Alexandru Matei wrote:
>>> Once VQs are filled with empty buffers and we kick the host,
>>> it can send connection requests. If 'the_virtio_vsock' is not
>>> initialized before, replies are silently dropped and do not reach the host.
>>>
>>> Fixes: 0deab087b16a ("vsock/virtio: use RCU to avoid use-after-free on the_virtio_vsock")
>>> Signed-off-by: Alexandru Matei <alexandru.matei@xxxxxxxxxx>
>>> ---
>>> v2:
>>> - split virtio_vsock_vqs_init in vqs_init and vqs_fill and moved
>>> the_virtio_vsock initialization after vqs_init
>>>
>>> net/vmw_vsock/virtio_transport.c | 9 +++++++--
>>> 1 file changed, 7 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
>>> index e95df847176b..92738d1697c1 100644
>>> --- a/net/vmw_vsock/virtio_transport.c
>>> +++ b/net/vmw_vsock/virtio_transport.c
>>> @@ -559,6 +559,11 @@ static int virtio_vsock_vqs_init(struct virtio_vsock *vsock)
>>> vsock->tx_run = true;
>>> mutex_unlock(&vsock->tx_lock);
>>>
>>> + return 0;
>>> +}
>>> +
>>> +static void virtio_vsock_vqs_fill(struct virtio_vsock *vsock)
>>
>> What about renaming this function in virtio_vsock_vqs_start() and move also the setting of `tx_run` here?
>
> It works but in this case we also need to move rcu_assign_pointer in virtio_vsock_vqs_start(),
> the assignment needs to be right after setting tx_run to true and before filling the VQs.
>
And if we move rcu_assign_pointer then there is no need to split the function in two,
We can move rcu_assign_pointer() directly inside virtio_vsock_vqs_init() after setting tx_run.
>>
>> Thanks,
>> Stefano
>>
>>> +{
>>> mutex_lock(&vsock->rx_lock);
>>> virtio_vsock_rx_fill(vsock);
>>> vsock->rx_run = true;
>>> @@ -568,8 +573,6 @@ static int virtio_vsock_vqs_init(struct virtio_vsock *vsock)
>>> virtio_vsock_event_fill(vsock);
>>> vsock->event_run = true;
>>> mutex_unlock(&vsock->event_lock);
>>> -
>>> - return 0;
>>> }
>>>
>>> static void virtio_vsock_vqs_del(struct virtio_vsock *vsock)
>>> @@ -664,6 +667,7 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
>>> goto out;
>>>
>>> rcu_assign_pointer(the_virtio_vsock, vsock);
>>> + virtio_vsock_vqs_fill(vsock);
>>>
>>> mutex_unlock(&the_virtio_vsock_mutex);
>>>
>>> @@ -736,6 +740,7 @@ static int virtio_vsock_restore(struct virtio_device *vdev)
>>> goto out;
>>>
>>> rcu_assign_pointer(the_virtio_vsock, vsock);
>>> + virtio_vsock_vqs_fill(vsock);
>>>
>>> out:
>>> mutex_unlock(&the_virtio_vsock_mutex);
>>> --
>>> 2.34.1
>>>
>>
