LISA auto/RW-G+RW-R1+RW-G+RW-R1 (* * Result: Maybe * * Process 0 starts (t=100000). * * P0 advances one grace period (t=200000). * * P1 -maybe- goes back a bit less than one grace period (t=101001). * * P2 advances one grace period (t=201002). * * P3 -maybe- goes back a bit less than one grace period (t=102003). * * Process 0 start at t=100000, process 4 end at t=102003: Cycle forbidden. *) { } P0 | P1 | P2 | P3 ; r[once] r1 x0 | f[rcu_read_lock] | r[once] r1 x2 | f[rcu_read_lock] ; f[sync] | r[once] r1 x1 | f[sync] | r[once] r1 x3 ; w[once] x1 1 | f[rcu_read_unlock] | w[once] x3 1 | f[rcu_read_unlock] ; | w[once] x2 1 | | w[once] x0 1 ; Observed 3:r1=1; 2:r1=0; 1:r1=1; 0:r1=1;