Multithreading

Question

How to fix the code so that there is no deadlock?

process INIT; common boolean C1. C2; common integer N; common real T1, T2;
begin С1:=false; С2:=false;
T1:= random; T2:= random;
N:=1;
start(P1); start(P2);
end;
process P1;
Begin while true do
begin BEFORE1;
C1:=true;
while C2 and (N<>1) do delay(T1);
CS1;
C1:=false; N:=2;
AFTER1;
end
end;
process P2;
Begin while true do
begin BEFORE2;
C2:=true;
while C1 and (N<>2) do delay(T2);
CS2;
C2:=false; N:=1;
AFTER2;
end
end;

Answer 1

In principle, I think both subprocesses should release all resources if they cannot immediately allocate all resources. Or at least release them after a limited number of attempts.