valgrind问题：“地址0x5203d4c在分配大小为0的块之前是4个字节”

Question

我是新来的，有一个问题要问你。由于uni中的分配，我遇到了内存问题。 我对eurovision系统进行编程，并使用structs方法。 我在这里复制了有问题的函数，包括valgrind输出。 我想要一些帮助， 谢谢。

eurovisionRunGetFriendlyStates function:

}

    if(eurovision == NULL){
        return NULL;
    }

    int *stateScoresId = malloc(eurovision->stateSize*sizeof(int));
    if(stateScoresId == NULL){
        return NULL;
    }

    int *stateScores = malloc(eurovision->stateSize*sizeof(int));
    if(stateScores == NULL){
        free(stateScoresId);
        return NULL;
    }

    int *statesCompareId = malloc(eurovision->stateSize*sizeof(int));
    if(statesCompareId == NULL){
        free(stateScores);
        free(stateScoresId);
        return NULL;
    }

    getSameStates(eurovision, stateScoresId, stateScores, statesCompareId);

    char** stateNames = malloc(sizeof(char*)*eurovision->stateSize);
    if(stateNames == NULL){
        free(statesCompareId);
        free(stateScores);
        free(stateScoresId);
        return NULL;
    }
    if(fillNames(eurovision, stateNames) == -1){
        free(stateNames);
        free(statesCompareId);
        free(stateScores);
        free(stateScoresId);
        return NULL;
    }

    sortByName(eurovision, statesCompareId, stateScoresId,
            eurovision->stateSize, stateNames);
    return makeFriendlyList(eurovision, statesCompareId, stateScoresId);

}sortByName function:

    if (n == 1) {
        return;
    }
    int i_max = indexOfMaxChar(names, n);
    int j_max = findState(eurovision, statesId, names, i_max);
    swap(&statesCompareId[n-1], &statesCompareId[j_max]);
    swap(&statesId[n-1], &statesId[j_max]);
    swapString(&names[n-1], &names[i_max]);
    sortByName(eurovision, statesCompareId, statesId, n-1, names);
}swap function:

    int tmp = *p;
    *p = *q;
    *q = tmp;
}
the valgrind output:
{

    ==28086== Invalid read of size 4
    ==28086==    at 0x401C94: swap (eurovision.c:599)
    ==28086==    by 0x402023: sortByName (eurovision.c:688)
    ==28086==    by 0x402077: sortByName (eurovision.c:690)
    ==28086==    by 0x402077: sortByName (eurovision.c:690)
     ==28086==    by 0x4016C0: eurovisionRunGetFriendlyStates     (eurovision.c:476)
     ==28086==    by 0x4048AB: testRunGetFriendlyStates (eurovisionTests.c:341)
        ==28086==    by 0x404C73: main (eurovisionTestsMain.c:23)
     ==28086==  Address 0x5203cc4 is 12 bytes before a block of size 0 alloc'd
     ==28086==    at 0x4C29BC3: malloc (vg_replace_malloc.c:299)
     ==28086==    by 0x401560: eurovisionRunGetFriendlyStates (eurovision.c:441)
     ==28086==    by 0x4048AB: testRunGetFriendlyStates (eurovisionTests.c:341)
     ==28086==    by 0x404C73: main (eurovisionTestsMain.c:23)

}