LISA auto/WW-G+WW-R+WW-G+WW-R
(*
* Result: Never
*
* Process 0 starts (t=100000).
*
* P0 advances one grace period (t=200000).
*
* P1 goes back a bit less than one grace period (t=101001).
*
* P2 advances one grace period (t=201002).
*
* P3 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 ;
w[once] x0 2 | f[rcu_read_lock] | w[once] x2 2 | f[rcu_read_lock] ;
f[sync] | w[once] x1 2 | 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] | | f[rcu_read_unlock] ;
Observed
x3=2; x2=1; x1=2; x0=2;