LISA LISAStern.2016.02.24a (* * Result: Sometimes * * Alan Stern test with code preceding an RCU read-side critical section * and a one-sided grace period. *) { x0 = 0; x1 = 0; x3 = 0; } P0 | P1 | P2 ; w[once] x0 1 | f[sync] | r[once] r2 x1 ; f[rcu_read_lock] | w[once] x2 1 | f[rmb] ; w[once] x1 1 | | r[once] r3 x0 ; r[once] r1 x2 | | ; f[rcu_read_unlock] | | ; Observed 2:r3=0; 2:r2=1; 0:r1=1;