LISA auto/WR-GH+WR-R+WR-R+WR-R (* * Result: Never * * Process 0 starts (t=100000). * * P0 advances three grace periods (t=400000). * * P1 goes back a bit less than one grace period (t=301001). * * P2 goes back a bit less than one grace period (t=202002). * * P3 goes back a bit less than one grace period (t=103003). * * Process 0 start at t=100000, process 4 end at t=103003: Cycle forbidden. *) { } P0 | P1 | P2 | P3 ; w[once] x0 2 | f[rcu_read_lock] | f[rcu_read_lock] | f[rcu_read_lock] ; f[sync] | w[once] x1 2 | w[once] x2 2 | w[once] x3 2 ; f[sync] | r[once] r2 x2 | r[once] r2 x3 | r[once] r2 x0 ; f[sync] | f[rcu_read_unlock] | f[rcu_read_unlock] | f[rcu_read_unlock] ; r[once] r2 x1 | | | ; Observed 3:r2=0; 2:r2=2; 1:r2=0; 0:r2=0;