having memory crash while multiple dequeue

[femady]

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <pthread.h>
#include <assert.h>
#include <sys/time.h>
#include <stdio.h>
#include "lfq.h"

void one_enq_and_multi_deq(pthread_t *threads);
void*  worker_s(void *);
void*  worker_c(void *);

struct timeval  tv1, tv2;
#define total_put 50000
int nthreads = 4; //sysconf(_SC_NPROCESSORS_ONLN); // Linux
int one_thread = 1;
int nthreads_exited = 0;
//lfqueue_t *myq;
struct lfq_ctx *myq;

void*  worker_c(void *arg) {
    int i = 0;
    int *int_data;
    int total_loop = total_put * (*(int*)arg);
    while (i++ < total_loop) {
        /*Dequeue*/
        while ((int_data = lfq_dequeue(myq)) == 0) {

        }
        //  printf("%d\n", *int_data);

        free(int_data);
    }
    __sync_add_and_fetch(&nthreads_exited, 1);
    return 0;
}

/** Worker Keep Sending at the same time, do not try instensively **/
void*  worker_s(void *arg)
{
    int i = 0, *int_data;
    int total_loop = total_put * (*(int*)arg);
    while (i++ < total_loop) {
        int_data = (int*)malloc(sizeof(int));
        assert(int_data != NULL);
        *int_data = i;
        /*Enqueue*/

        while (lfq_enqueue(myq, int_data)) {
            // printf("ENQ FULL?\n");
        }
    }
    // __sync_add_and_fetch(&nthreads_exited, 1);
    return 0;
}

#define detach_thread_and_loop \
for (i = 0; i < nthreads; i++)\
pthread_detach(threads[i]);\
while ( nthreads_exited < nthreads ) \
    usleep(2000);\
if(myq->count != 0){\
usleep(2000);\
printf("current size= %d\n", myq->count);\
}

void one_enq_and_multi_deq(pthread_t *threads) {
    printf("-----------%s---------------\n", "one_enq_and_multi_deq");
    int i;
    for (i = 0; i < nthreads; i++)
        pthread_create(threads + i, NULL, worker_c, &one_thread);

    worker_s(&nthreads);

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wimplicit-function-declaration"
    detach_thread_and_loop;
#pragma GCC diagnostic pop
}

int main(void)
{
    int n;

    myq = malloc(sizeof (struct lfq_ctx));
    lfq_init(myq, 4);

    for (n = 0; n < 1000; n++) {
        printf("Current running at =%d, ", n);
        nthreads_exited = 0;

        /* Spawn threads. */
        pthread_t threads[nthreads];
        printf("Using %d thread%s.\n", nthreads, nthreads == 1 ? "" : "s");
        printf("Total requests %d \n", total_put);
        gettimeofday(&tv1, NULL);

        one_enq_and_multi_deq(threads);
        //one_deq_and_multi_enq(threads);
        // multi_enq_deq(threads);

        gettimeofday(&tv2, NULL);
        printf ("Total time = %f seconds\n",
                (double) (tv2.tv_usec - tv1.tv_usec) / 1000000 +
                (double) (tv2.tv_sec - tv1.tv_sec));

        //getchar();
        usleep(1000);
        assert ( 0 == myq->count && "Error, all queue should be consumed but not");
    }
    lfq_clean(myq);
    free(myq);
    return 0;
}

[darkautism]

Thanks for your report. @pcordes 's code seems resolved this bug.

[femady]

Issue still existed. By the time you hazard pointer not found the pointer and going to free, at the same time the pointer has put into your hazard pointer.

[darkautism]

Your screenshot not like new code.

Newest lfq_dequeue_tid:

void * lfq_dequeue_tid(struct lfq_ctx *ctx, int tid ) {
    //int cn_runtimes = 0;
    volatile struct lfq_node *old_head, *new_head;
#if 1  // HP[tid] stuff is necessary for deallocation.  (but it's still not safe).
    do {

I still run this test code on latest code, but still no hit crash. Only crash on old test script. https://github.com/darkautism/lfqueue/pull/7#issuecomment-419326061

Did you mind put this testing code into this repository?

[femady]

Thanks for mentioned, i re-clone your newest project and run it. Issue Solved.