LISA LISA2R1G (* * Result: Sometimes * * One RCU grace period with a pair of RCU read-side critical sections. * These critical sections can therefore overlap. Cycle allowed. *) { x0 = 0; x1 = 0; x2 = 0; } P0 | P1 | P2 ; f[rcu_read_lock] | r[once] r1 x1 | f[rcu_read_lock] ; r[once] r2 x0 | f[sync] | r[once] r2 x2 ; w[once] x1 1 | w[once] x2 1 | w[once] x0 1 ; f[rcu_read_unlock] | | f[rcu_read_unlock] ; Observed 2:r2=1; 1:r1=1; 0:r2=1;