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C SB+mbonceonces
(*
* Result: Never
*
* This litmus test demonstrates that full memory barriers suffice to
* order the store-buffering pattern, where each process writes to the
* variable that the preceding process reads. (Locking and RCU can also
* suffice, but not much else.)
*)
{}
P0(int *x, int *y)
{
int r0;
WRITE_ONCE(*x, 1);
smp_mb();
r0 = READ_ONCE(*y);
}
P1(int *x, int *y)
{
int r0;
WRITE_ONCE(*y, 1);
smp_mb();
r0 = READ_ONCE(*x);
}
exists (0:r0=0 /\ 1:r0=0)
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