LISA auto/WR-G+WR-R+WR-R+WR-R (* * Result: Sometimes * * Process 0 starts (t=296997). * * P0 advances one grace period (t=396997). * * P1 goes back a bit less than one grace period (t=297998). * * P2 goes back a bit less than one grace period (t=198999). * * P3 goes back a bit less than one grace period (t=100000). * * Process 0 start at t=296997, process 4 end at t=100000: Cycle allowed. *) { } 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 ; r[once] r2 x1 | r[once] r2 x2 | r[once] r2 x3 | r[once] r2 x0 ; | f[rcu_read_unlock] | f[rcu_read_unlock] | f[rcu_read_unlock] ; Observed 3:r2=0; 2:r2=0; 1:r2=0; 0:r2=0;