static int snd_seq_ioctl_set_queue_client(struct snd_seq_client *client,
					  void *arg)
{
	struct snd_seq_queue_client *info = arg;
	int err;

	if (info->used >= 0) {
		err = snd_seq_queue_use(info->queue, client->number, info->used);
		if (err < 0)
			return err;
	}

	return snd_seq_ioctl_get_queue_client(client, arg);
}

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 Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.