static int snd_seq_ioctl_set_client_pool(struct snd_seq_client *client,
					 void *arg)
{
	struct snd_seq_client_pool *info = arg;
	int rc;

	if (client->number != info->client)
		return -EINVAL; /* can't change other clients */

	if (info->output_pool >= 1 && info->output_pool <= SNDRV_SEQ_MAX_EVENTS &&
	    (! snd_seq_write_pool_allocated(client) ||
	     info->output_pool != client->pool->size)) {
		if (snd_seq_write_pool_allocated(client)) {
			/* remove all existing cells */
			snd_seq_pool_mark_closing(client->pool);
			snd_seq_queue_client_leave_cells(client->number);
			snd_seq_pool_done(client->pool);
		}
		client->pool->size = info->output_pool;
		rc = snd_seq_pool_init(client->pool);
		if (rc < 0)
			return rc;
	}
	if (client->type == USER_CLIENT && client->data.user.fifo != NULL &&
	    info->input_pool >= 1 &&
	    info->input_pool <= SNDRV_SEQ_MAX_CLIENT_EVENTS &&
	    info->input_pool != client->data.user.fifo_pool_size) {
		/* change pool size */
		rc = snd_seq_fifo_resize(client->data.user.fifo, info->input_pool);
		if (rc < 0)
			return rc;
		client->data.user.fifo_pool_size = info->input_pool;
	}
	if (info->output_room >= 1 &&
	    info->output_room <= client->pool->size) {
		client->pool->room  = info->output_room;
	}

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 Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.