static int ion_debug_heap_show(struct seq_file *s, void *unused)
{
	struct ion_heap *heap = s->private;
	struct ion_device *dev = heap->dev;
	struct rb_node *n;
	size_t total_size = 0;
	size_t total_orphaned_size = 0;

	seq_printf(s, "%16s %16s %16s\n", "client", "pid", "size");
	seq_puts(s, "----------------------------------------------------\n");

	mutex_lock(&debugfs_mutex);
	for (n = rb_first(&dev->clients); n; n = rb_next(n)) {
		struct ion_client *client = rb_entry(n, struct ion_client,
						     node);
		size_t size = ion_debug_heap_total(client, heap->id);

		if (!size)
			continue;
		if (client->task) {
			char task_comm[TASK_COMM_LEN];

			get_task_comm(task_comm, client->task);
			seq_printf(s, "%16s %16u %16zu\n", task_comm,
				   client->pid, size);
		} else {
			seq_printf(s, "%16s %16u %16zu\n", client->name,
				   client->pid, size);
		}
	}
	mutex_unlock(&debugfs_mutex);

	seq_puts(s, "----------------------------------------------------\n");
	seq_puts(s, "orphaned allocations (info is from last known client):\n");
	mutex_lock(&dev->buffer_lock);
	for (n = rb_first(&dev->buffers); n; n = rb_next(n)) {
		struct ion_buffer *buffer = rb_entry(n, struct ion_buffer,
						     node);
		if (buffer->heap->id != heap->id)
			continue;
		total_size += buffer->size;
		if (!buffer->handle_count) {
			seq_printf(s, "%16s %16u %16zu %d %d\n",
				   buffer->task_comm, buffer->pid,
				   buffer->size, buffer->kmap_cnt,
				   atomic_read(&buffer->ref.refcount));
			total_orphaned_size += buffer->size;
		}
	}
	mutex_unlock(&dev->buffer_lock);
	seq_puts(s, "----------------------------------------------------\n");
	seq_printf(s, "%16s %16zu\n", "total orphaned",
		   total_orphaned_size);
	seq_printf(s, "%16s %16zu\n", "total ", total_size);
	if (heap->flags & ION_HEAP_FLAG_DEFER_FREE)
		seq_printf(s, "%16s %16zu\n", "deferred free",
				heap->free_list_size);
	seq_puts(s, "----------------------------------------------------\n");

	if (heap->debug_show)
		heap->debug_show(heap, s, unused);

	return 0;
}

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.