当C中存在冲突（使用单独的链接）时，无法释放哈希表中的节点

好的，我有一个我在C中制作的哈希表 . 我使用单独的链接（链表）来解决冲突 . 我注意到如果没有碰撞并且每个项目都散列到它自己的索引，我可以释放整个表 . 但是如果存在冲突且我在索引处有多个值，则它只能释放该索引中的第一个值而不是剩余值 . 当程序尝试释放该索引处的其他程序时崩溃 . 我尝试调试它，我意识到那些其他值已经设置为NULL，我不知道为什么，因为当我将它们插入到表中时我正在使用malloc . 我知道我错过了什么 . 如果有人可以提供帮助那就太棒了，因为我一直试图解决这个问题几个小时：/

这是代码：

int symTabSearch(struct hashTable * h, char * label);
int insertToSymTab(struct hashTable * h, char * label, int locctr);

struct listNode
{
    char * label;
    int address;
    struct listNode * next;
};

struct hashTableNode
{
    int blockCount;         //number of elements in a block
    struct listNode * firstNode;
};

struct hashTable
{
    int tableSize;
    int count;              //number of elements in the table
    struct hashTableNode * table;
};

struct hashTable * createHashTable(int size)
{
    struct hashTable * ht;
    ht = (struct hashTable*)malloc(sizeof(struct hashTable));

    if (!ht)
        return NULL;

    ht->tableSize = size;
    ht->count = 0;
    ht->table = (struct hashTableNode *)malloc(sizeof(struct hashTableNode) * ht->tableSize);

    if (!ht->table)
    {
        printf("Memory error\n");
        return NULL;
    }

    int i;
    for (i = 0; i < ht->tableSize; i++)
    {
        ht->table[i].blockCount = 0;
        ht->table[i].firstNode = NULL;
    }

    return ht;
}

/*hash function: adds up the ascii values of each
character, multiplies by a prime number (37) and mods the sum wih the table size*/
int hash(char * label, int tableSize)
{
    int hashVal = 0;
    size_t i;

    for (i = 0; i < strlen(label); i++)
        hashVal = 37 * hashVal + label[i];

    hashVal %= tableSize;
    if (hashVal < 0)
        hashVal += tableSize;

    return hashVal;
}

int symTabSearch(struct hashTable * h, char * label)
{
    struct listNode * temp;
    temp = h->table[hash(label, h->tableSize)].firstNode; //temp points to the first listNode in table[hashedIndex]

    while (temp)
    {
        if (strcmp(temp->label, label) == 0)
            return 1;   //found

        temp = temp->next;      //go to next link
    }
    return 0;   //not found
}

int insertToSymTab(struct hashTable * h, char * label, int locctr)
{
    int index;
    struct listNode * currentNode, *newNode;

    index = hash(label, h->tableSize);
    currentNode = h->table[index].firstNode;

    newNode = (struct listNode *)malloc(sizeof(struct listNode));
    newNode->label = (char *)malloc(sizeof(char) * 7);  //allocates 7 chars to store label up to 6 chars long (0-5), last one is for the '\0'

    if (!newNode)   //if new node is null
    {
        printf("Error creating new node\n");
        return 0;
    }

    strcpy(newNode->label, label);
    newNode->address = locctr;

    if (h->table[index].firstNode == NULL)      //if first node at table index is empty
    {
        h->table[index].firstNode = newNode;
        h->table[index].firstNode->next = NULL;
    }
    else
    {                                           //firstNode was not empty, so chain newNode to the next empty node
        while (currentNode != NULL)             //go to next available node
            currentNode = currentNode->next;

        currentNode = newNode;
        currentNode->next = NULL;
    }

    h->table[index].blockCount++;
    h->count++;
    return 1;
}

void freeHashTable(struct hashTable * h)        //might not free memory properly, might crash too, test later
{
    int i, j;
    struct listNode * current, *temp;
    char * tempStr;

    if (!h)     //make sure table even has memory to be freed
        return;

    for (i = 0; i < h->tableSize; i++)
    {
        current = h->table[i].firstNode;
        for (j = 0; j < h->table[i].blockCount; j++)
        {
            temp = current;
            tempStr = current->label;
            current = current->next;
            free(temp);
            free(tempStr);
            temp = NULL;
            tempStr = NULL;
        }
    }

    free(h->table);
    h->table = NULL;
    free(h);
    h = NULL;
}