LISA auto/WR-G+WR-R+WR-G+WR-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 ;
r[once] r2 x1 | r[once] r2 x2 | r[once] r2 x3 | r[once] r2 x0 ;
| f[rcu_read_unlock] | | f[rcu_read_unlock] ;
Observed
3:r2=0; 2:r2=0; 1:r2=2; 0:r2=0;