Simple example that Relacy cannot fails to find error(assert)

[klba...@gmail.com]

Hi. Why assertion passed but it must fail?
I wrote execution order in comments in which the assertion must fail.

struct data_race_test : rl::test_suite<data_race_test, 2>{
    rl::atomic<int> ff;
    rl::atomic<int> nexec;

    void before(){
        nexec($) = 0;
        ff($) = 0;
    }

    void thread(unsigned id){
        if(id == 0){
            // Thread 0
            if(ff($)==0){       // 1.           7.
                ff($)++;        // 2 ff=1.      8 ff=1.
                nexec($)++;     // 3 nexec=1.   9 nexec=2.
                assertions1();  // 4.           10 must fail but dont!
            }else{
                ff($)++;
            }
        }else if(id == 1){
            // Thread 1
            if(nexec($)>0){     // 5.
                ff($)--;        // 6 ff=0.
                if(ff($)==0){
                    nexec($)--;
                    assertions1();
                }
            }
        }
    }

    void assertions1(){
        int ex = nexec($);
        RL_ASSERT(ex >= 0 && ex<=1);
    }
};

int main(){
    rl::test_params p;
    p.search_type = rl::sched_full;
    //p.iteration_count = 1000000;

    rl::simulate<data_race_test>(p);
}

[Dmitry Vyukov]

Hello,

You create only 2 threads, but seem to assume that 3 threads are running.

You need to create 3 threads:

struct data_race_test : rl::test_suite<data_race_test, 3>{

And then execute first part of code by 2 threads:

if(id == 0 || id == 2){

Note the test executed multiple times, but each run starts from clean
slate. No state is accumulated between runs.


--
Dmitry Vyukov

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