C C-R+o-wmb-o+o+mb+o.litmus

{
}

P0(int *a, int *b)
{
	WRITE_ONCE(*a, 1);
	smp_wmb();
	WRITE_ONCE(*b, 1);
}

P1(int *a, int *b)
{
	int r1;

	WRITE_ONCE(*b, 2);
	smp_mb();
	r1 = READ_ONCE(*a);
}

exists
(b=2 /\ 1:r1=0)