1C SB+fencembonceonces
2
3(*
4 * Result: Never
5 *
6 * This litmus test demonstrates that full memory barriers suffice to
7 * order the store-buffering pattern, where each process writes to the
8 * variable that the preceding process reads.  (Locking and RCU can also
9 * suffice, but not much else.)
10 *)
11
12{
13	int x;
14	int y;
15}
16
17P0(int *x, int *y)
18{
19	int r0;
20
21	WRITE_ONCE(*x, 1);
22	smp_mb();
23	r0 = READ_ONCE(*y);
24}
25
26P1(int *x, int *y)
27{
28	int r0;
29
30	WRITE_ONCE(*y, 1);
31	smp_mb();
32	r0 = READ_ONCE(*x);
33}
34
35exists (0:r0=0 /\ 1:r0=0)
36