Q: Given the following code slice:
```
1 void vmbus_free_ring(struct vmbus_channel *channel)
2 {
3 	hv_ringbuffer_cleanup(&channel->outbound);
4 	hv_ringbuffer_cleanup(&channel->inbound);
5 
6 	if (channel->ringbuffer_page) {
7 		__free_pages(channel->ringbuffer_page,
8 			     get_order(channel->ringbuffer_pagecount
9 				       << PAGE_SHIFT));
10 		channel->ringbuffer_page = NULL;
11 	}
12 }
```
which has a vulnerability among CWE-401,CWE-476 and among lines:
```
7 		__free_pages(channel->ringbuffer_page,
8 			     get_order(channel->ringbuffer_pagecount
```
Please generate five possible patches for the vulnerability.