init
idle p0 started
t2 p4 called 1 time
enter lock s4 0
t3 p4 exit
idle enter lock s3 0
idle pend t0
idle pend t1
idle pend t2
t2 p4 called 2 times
enter lock s4 1
t3 p4 exit
idle still in lock s3 0
t1 p3 called 1 time
t1 enter lock s4 2
t1 pend t0
t1 pend t2
t1 still in lock s4 2
t2 p4 called 3 times
enter lock s4 2
t3 p4 exit
t1 p3 exit
t0 p2 called 1 time
t0 p2 exit

back in idle
enter lock s2 0
idle pend t0
idle pend t1
t1 p3 called 2 times
t1 enter lock s4 3
t1 pend t0
t1 pend t2
t1 still in lock s4 3
t2 p4 called 4 times
enter lock s4 3
t3 p4 exit
t1 p3 exit
idle pend t2
t2 p4 called 5 times
enter lock s4 4
t3 p4 exit
idle still in lock s2 0
t0 p2 called 2 times
t0 p2 exit

idle exit