struct usb_device *usb_dev = interface_to_usbdev(intf);
        struct usbatm_data *instance;
        char *buf;
+       size_t instance_size = sizeof(*instance) + sizeof(struct urb *) * (num_rcv_urbs + num_snd_urbs);
        int error = -ENOMEM;
        int i, length;
        int need_heavy;
                        intf->altsetting->desc.bInterfaceNumber);
 
        /* instance init */
-       instance = kmalloc(sizeof(*instance) + sizeof(struct urb *) * (num_rcv_urbs + num_snd_urbs),
-                          GFP_KERNEL);
+       instance = kmalloc(instance_size, GFP_KERNEL);
        if (!instance) {
                dev_dbg(dev, "%s: no memory for instance data!\n", __func__);
                return -ENOMEM;
        }
 
-       memset(instance, 0, sizeof(*instance));
+       memset(instance, 0, instance_size);
 
        /* public fields */
 
                        goto fail_unbind;
                }
 
+               instance->urbs[i] = urb;
+
                buffer = kmalloc(channel->buf_size, GFP_KERNEL);
                if (!buffer) {
                        dev_dbg(dev, "%s: no memory for buffer %d!\n", __func__, i);
 
                vdbg("%s: alloced buffer 0x%p buf size %u urb 0x%p",
                     __func__, urb->transfer_buffer, urb->transfer_buffer_length, urb);
-               instance->urbs[i] = urb;
        }
 
        if (need_heavy && driver->heavy_init) {