Subject: Re: [1/1] connector/CBUS: new messaging subsystem. Revision number next.

From: Dmitry Torokhov <[email-masked]>
Date: Tue, 26 Apr 2005 10:57:55 -0500

Hi Evgeniy,

On 4/11/05, Evgeniy Polyakov <[email-masked]> wrote:
> /*****************************************/
> Kernel Connector.
> /*****************************************/
...
> +static int cn_call_callback(struct cn_msg *msg, void (*destruct_data) (void *), void *data)
> +{
> +       struct cn_callback_entry *__cbq;
> +       struct cn_dev *dev = &cdev;
> +       int found = 0;
> +
> +       spin_lock_bh(&dev->cbdev->queue_lock);
> +       list_for_each_entry(__cbq, &dev->cbdev->queue_list, callback_entry) {
> +               if (cn_cb_equal(&__cbq->cb->id, &msg->id)) {
> +                       __cbq->cb->priv = msg;
> +
> +                       __cbq->ddata = data;
> +                       __cbq->destruct_data = destruct_data;
> +
> +                       queue_work(dev->cbdev->cn_queue, &__cbq->work);

It looks like there is a problem with the code. As far as I can see
there is only one cn_callback_entry associated with each callback. So,
if someone sends netlink messages with the same id at a high enough
rate (so cbdev's work queue does not get a chance to get scheduled and
process pending requests) ddata and the destructor will be overwritten
which can lead to memory leaks and non-delivery of some messages.

Am I missing something?

-- 
Dmitry