static bool kvm_get_time_and_clockread(s64 *kernel_ns, cycle_t *cycle_now)
{
	/* checked again under seqlock below */
	if (pvclock_gtod_data.clock.vclock_mode != VCLOCK_TSC)
		return false;

	return do_monotonic_boot(kernel_ns, cycle_now) == VCLOCK_TSC;
}

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.