num = min(num, ARRAY_SIZE(vb->pfns));
mutex_lock(&vb->balloon_lock);
+ /* We can't release more pages than taken */
+ num = min(num, (size_t)vb->num_pages);
for (vb->num_pfns = 0; vb->num_pfns < num;
vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) {
page = balloon_page_dequeue(vb_dev_info);