Test Weak-RCU-Readers-With-Grace

LISA Weak-RCU-Readers-With-Grace (*Paul says allowed since mid June*)
{
x = 0; y = 0; z = 0;
}
 P0                 | P1           | P2                 ;
 f[rcu_read_lock]   |              | f[rcu_read_lock]   ;
 r[once] r1 y       | r[once] r2 x | r[once] r3 z       ;
                    | f[sync]      |                    ;
 w[once] x 1        | w[once] z 1  | w[once] y 1        ;
 f[rcu_read_unlock] |              | f[rcu_read_unlock] ;
Observed
    2:r3=1; 1:r2=1; 0:r1=1;