LISA auto/WW-G+WW-B+WW-G+WW-R (* * Result: Never * * Process 0 starts (t=100000). * * P0 advances one grace period (t=200000). * * P1 advances slightly (t=200002). * * P2 advances one grace period (t=300003). * * P3 goes back a bit less than one grace period (t=201004). * * Process 0 start at t=100000, process 4 end at t=201004: Cycle forbidden. *) { } P0 | P1 | P2 | P3 ; w[once] x0 2 | w[once] x1 2 | w[once] x2 2 | f[rcu_read_lock] ; f[sync] | f[mb] | f[sync] | w[once] x3 2 ; w[once] x1 1 | w[once] x2 1 | w[once] x3 1 | w[once] x0 1 ; | | | f[rcu_read_unlock] ; Observed x3=2; x2=1; x1=2; x0=2;