Test SB-unlock-lock

C SB-unlock-lock

{}

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

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

P1(int *x, int *y, spinlock_t *v)
{
 int r0;

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

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