linux-arkmicro/linux/tools/memory-model/litmus-tests/ISA2+pooncelock+pooncelock+pombonce.litmus

C ISA2+pooncelock+pooncelock+pombonce

(*
 * Result: Sometimes
 *
 * This test shows that the ordering provided by a lock-protected S
 * litmus test (P0() and P1()) are not visible to external process P2().
 * This is likely to change soon.
 *)

{}

P0(int *x, int *y, spinlock_t *mylock)
{
	spin_lock(mylock);
	WRITE_ONCE(*x, 1);
	WRITE_ONCE(*y, 1);
	spin_unlock(mylock);
}

P1(int *y, int *z, spinlock_t *mylock)
{
	int r0;

	spin_lock(mylock);
	r0 = READ_ONCE(*y);
	WRITE_ONCE(*z, 1);
	spin_unlock(mylock);
}

P2(int *x, int *z)
{
	int r1;
	int r2;

	r2 = READ_ONCE(*z);
	smp_mb();
	r1 = READ_ONCE(*x);
}

exists (1:r0=1 /\ 2:r2=1 /\ 2:r1=0)