LISA auto/RW-Rs+RW-RD+RW-R (* * Result: Sometimes * * Process 0 starts (t=198996). * * P0 advances slightly (t=198997). * * P1 advances slightly (t=198999). * * P2 goes back a bit less than one grace period (t=100000). * * Process 0 start at t=198996, process 3 end at t=100000: Cycle allowed. *) { 0:r3=x2; x1=y2; 1:r4=y2; } P0 | P1 | P2 ; f[rcu_read_lock] | f[rcu_read_lock] | f[rcu_read_lock] ; r[once] r1 x0 | r[deref] r1 x1 | r[once] r1 x2 ; w[assign] x1 r3 | w[once] r1 1 | w[once] x0 1 ; f[rcu_read_unlock] | f[rcu_read_unlock] | f[rcu_read_unlock] ; Observed 2:r1=1; 1:r1=x2; 0:r1=1;