1C Z6.0+pooncelock+poonceLock+pombonce
2
3(*
4 * Result: Never
5 *
6 * This litmus test demonstrates how smp_mb__after_spinlock() may be
7 * used to ensure that accesses in different critical sections for a
8 * given lock running on different CPUs are nevertheless seen in order
9 * by CPUs not holding that lock.
10 *)
11
12{
13	spinlock_t mylock;
14	int x;
15	int y;
16	int z;
17}
18
19P0(int *x, int *y, spinlock_t *mylock)
20{
21	spin_lock(mylock);
22	WRITE_ONCE(*x, 1);
23	WRITE_ONCE(*y, 1);
24	spin_unlock(mylock);
25}
26
27P1(int *y, int *z, spinlock_t *mylock)
28{
29	int r0;
30
31	spin_lock(mylock);
32	smp_mb__after_spinlock();
33	r0 = READ_ONCE(*y);
34	WRITE_ONCE(*z, 1);
35	spin_unlock(mylock);
36}
37
38P2(int *x, int *z)
39{
40	int r1;
41
42	WRITE_ONCE(*z, 2);
43	smp_mb();
44	r1 = READ_ONCE(*x);
45}
46
47exists (1:r0=1 /\ z=2 /\ 2:r1=0)
48