1C MP+polockmbonce+poacquiresilsil
 2
 3(*
 4 * Result: Never
 5 *
 6 * Do spinlocks combined with smp_mb__after_spinlock() provide order
 7 * to outside observers using spin_is_locked() to sense the lock-held
 8 * state, ordered by acquire?  Note that when the first spin_is_locked()
 9 * returns false and the second true, we know that the smp_load_acquire()
10 * executed before the lock was acquired (loosely speaking).
11 *)
12
13{}
14
15P0(spinlock_t *lo, int *x) // Producer
16{
17	spin_lock(lo);
18	smp_mb__after_spinlock();
19	WRITE_ONCE(*x, 1);
20	spin_unlock(lo);
21}
22
23P1(spinlock_t *lo, int *x) // Consumer
24{
25	int r1;
26	int r2;
27	int r3;
28
29	r1 = smp_load_acquire(x);
30	r2 = spin_is_locked(lo);
31	r3 = spin_is_locked(lo);
32}
33
34exists (1:r1=1 /\ 1:r2=0 /\ 1:r3=1) (* Bad outcome. *)

 1C MP+polockmbonce+poacquiresilsil
 2
 3(*
 4 * Result: Never
 5 *
 6 * Do spinlocks combined with smp_mb__after_spinlock() provide order
 7 * to outside observers using spin_is_locked() to sense the lock-held
 8 * state, ordered by acquire?  Note that when the first spin_is_locked()
 9 * returns false and the second true, we know that the smp_load_acquire()
10 * executed before the lock was acquired (loosely speaking).
11 *)
12
13{}
14
15P0(spinlock_t *lo, int *x) // Producer
16{
17	spin_lock(lo);
18	smp_mb__after_spinlock();
19	WRITE_ONCE(*x, 1);
20	spin_unlock(lo);
21}
22
23P1(spinlock_t *lo, int *x) // Consumer
24{
25	int r1;
26	int r2;
27	int r3;
28
29	r1 = smp_load_acquire(x);
30	r2 = spin_is_locked(lo);
31	r3 = spin_is_locked(lo);
32}
33
34exists (1:r1=1 /\ 1:r2=0 /\ 1:r3=1) (* Bad outcome. *)