task_function_call(struct task_struct *p, remote_function_f func, void *info)
{
	struct remote_function_call data = {
		.p	= p,
		.func	= func,
		.info	= info,
		.ret	= -EAGAIN,
	};
	int ret;

	do {
		ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1);
		if (!ret)
			ret = data.ret;
	} while (ret == -EAGAIN);

	return ret;
}

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.