Test lock-write2

C lock-write2

(* Expected result: allowed *)

{
}

P0(int *x, int *y, spinlock_t *s)
{
 int r0;

 WRITE_ONCE(*x, 1);
 smp_wmb();
 spin_lock(s);
 r0 = READ_ONCE(*y);
 spin_unlock(s);
}

P1(int *x, int *y)
{
 int r1;

 WRITE_ONCE(*y, 1);
 smp_mb();
 r1 = READ_ONCE(*x);
}

Observed
    1:r1=0; 0:r0=0;