/
Locks2.tla
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Locks2.tla
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------------------------------- MODULE Locks2 -------------------------------
EXTENDS Naturals, TLC
(* --algorithm DeadlockEmpire
variables mutex = 0; mutex2 = 0;
mutexOwner = 0; mutex2Owner = 0;
process Left = 1
begin
L1: await (mutex = 0 \/ mutexOwner = 1); \* Monitor.Enter(mutex);
mutex := mutex + 1;
mutexOwner := 1;
L2: await (mutex2 = 0 \/ mutex2Owner = 1); \* Monitor.Enter(mutex2);
mutex2 := mutex2 + 1;
mutex2Owner := 1;
L3: skip;
L4: mutex := mutex - 1; \* Monitor.Exit(mutex);
if (mutex = 0) then mutexOwner := 0; end if;
L5: mutex2 := mutex2 - 1; \* Monitor.Exit(mutex2);
if (mutex2 = 0) then mutex2Owner := 0; end if;
end process;
process Right = 2
begin
R1: await (mutex2 = 0 \/ mutex2Owner = 2); \* Monitor.Enter(mutex2);
mutex2 := mutex2 + 1;
mutex2Owner := 2;
R2: await (mutex = 0 \/ mutexOwner = 2); \* Monitor.Enter(mutex);
mutex := mutex + 1;
mutexOwner := 2;
R3: skip;
R4: await (mutex2 = 0 \/ mutex2Owner = 2); \* Monitor.Enter(mutex2);
mutex2 := mutex2 + 1;
mutex2Owner := 2;
R5: mutex:= mutex - 1; \* Monitor.Exit(mutex);
if (mutex = 0) then mutexOwner := 0; end if;
end process;
end algorithm *)
\* BEGIN TRANSLATION
VARIABLES mutex, mutex2, mutexOwner, mutex2Owner, pc
vars == << mutex, mutex2, mutexOwner, mutex2Owner, pc >>
ProcSet == {1} \cup {2}
Init == (* Global variables *)
/\ mutex = 0
/\ mutex2 = 0
/\ mutexOwner = 0
/\ mutex2Owner = 0
/\ pc = [self \in ProcSet |-> CASE self = 1 -> "L1"
[] self = 2 -> "R1"]
L1 == /\ pc[1] = "L1"
/\ (mutex = 0 \/ mutexOwner = 1)
/\ mutex' = mutex + 1
/\ mutexOwner' = 1
/\ pc' = [pc EXCEPT ![1] = "L2"]
/\ UNCHANGED << mutex2, mutex2Owner >>
L2 == /\ pc[1] = "L2"
/\ (mutex2 = 0 \/ mutex2Owner = 1)
/\ mutex2' = mutex2 + 1
/\ mutex2Owner' = 1
/\ pc' = [pc EXCEPT ![1] = "L3"]
/\ UNCHANGED << mutex, mutexOwner >>
L3 == /\ pc[1] = "L3"
/\ TRUE
/\ pc' = [pc EXCEPT ![1] = "L4"]
/\ UNCHANGED << mutex, mutex2, mutexOwner, mutex2Owner >>
L4 == /\ pc[1] = "L4"
/\ mutex' = mutex - 1
/\ IF (mutex' = 0)
THEN /\ mutexOwner' = 0
ELSE /\ TRUE
/\ UNCHANGED mutexOwner
/\ pc' = [pc EXCEPT ![1] = "L5"]
/\ UNCHANGED << mutex2, mutex2Owner >>
L5 == /\ pc[1] = "L5"
/\ mutex2' = mutex2 - 1
/\ IF (mutex2' = 0)
THEN /\ mutex2Owner' = 0
ELSE /\ TRUE
/\ UNCHANGED mutex2Owner
/\ pc' = [pc EXCEPT ![1] = "Done"]
/\ UNCHANGED << mutex, mutexOwner >>
Left == L1 \/ L2 \/ L3 \/ L4 \/ L5
R1 == /\ pc[2] = "R1"
/\ (mutex2 = 0 \/ mutex2Owner = 2)
/\ mutex2' = mutex2 + 1
/\ mutex2Owner' = 2
/\ pc' = [pc EXCEPT ![2] = "R2"]
/\ UNCHANGED << mutex, mutexOwner >>
R2 == /\ pc[2] = "R2"
/\ (mutex = 0 \/ mutexOwner = 2)
/\ mutex' = mutex + 1
/\ mutexOwner' = 2
/\ pc' = [pc EXCEPT ![2] = "R3"]
/\ UNCHANGED << mutex2, mutex2Owner >>
R3 == /\ pc[2] = "R3"
/\ TRUE
/\ pc' = [pc EXCEPT ![2] = "R4"]
/\ UNCHANGED << mutex, mutex2, mutexOwner, mutex2Owner >>
R4 == /\ pc[2] = "R4"
/\ (mutex2 = 0 \/ mutex2Owner = 2)
/\ mutex2' = mutex2 + 1
/\ mutex2Owner' = 2
/\ pc' = [pc EXCEPT ![2] = "R5"]
/\ UNCHANGED << mutex, mutexOwner >>
R5 == /\ pc[2] = "R5"
/\ mutex' = mutex - 1
/\ IF (mutex' = 0)
THEN /\ mutexOwner' = 0
ELSE /\ TRUE
/\ UNCHANGED mutexOwner
/\ pc' = [pc EXCEPT ![2] = "Done"]
/\ UNCHANGED << mutex2, mutex2Owner >>
Right == R1 \/ R2 \/ R3 \/ R4 \/ R5
Next == Left \/ Right
\/ (* Disjunct to prevent deadlock on termination *)
((\A self \in ProcSet: pc[self] = "Done") /\ UNCHANGED vars)
Spec == Init /\ [][Next]_vars
Termination == <>(\A self \in ProcSet: pc[self] = "Done")
\* END TRANSLATION
Assertions == mutex >= 0 /\ mutex2 >= 0
CriticalSections == {pc[1],pc[2]} /= {"L3", "R3"}
=============================================================================
\* Modification History
\* Last modified Tue Apr 02 01:13:13 PDT 2019 by ejacobus
\* Created Mon Apr 01 01:15:27 PDT 2019 by ejacobus