1C Z6.0+pooncelock+pooncelock+pombonce
 2
 3(*
 4 * Result: Sometimes
 5 *
 6 * This example demonstrates that a pair of accesses made by different
 7 * processes each while holding a given lock will not necessarily be
 8 * seen as ordered by a third process not holding that lock.
 9 *)
10
11{}
12
13P0(int *x, int *y, spinlock_t *mylock)
14{
15	spin_lock(mylock);
16	WRITE_ONCE(*x, 1);
17	WRITE_ONCE(*y, 1);
18	spin_unlock(mylock);
19}
20
21P1(int *y, int *z, spinlock_t *mylock)
22{
23	int r0;
24
25	spin_lock(mylock);
26	r0 = READ_ONCE(*y);
27	WRITE_ONCE(*z, 1);
28	spin_unlock(mylock);
29}
30
31P2(int *x, int *z)
32{
33	int r1;
34
35	WRITE_ONCE(*z, 2);
36	smp_mb();
37	r1 = READ_ONCE(*x);
38}
39
40exists (1:r0=1 /\ z=2 /\ 2:r1=0)