Valgrind 告诉我我有与 mallocs 相同数量的 free，但仍然给我错误

Question

当我运行 valgrind 检查内存泄漏时，我得到了一些错误，尽管它说我调用 malloc 的次数与 free 相同，这应该意味着我释放了所有内存。

// Implements a dictionary's functionality
#include <ctype.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "dictionary.h"

// Represents a node in a hash table
typedef struct node
{
    char word[LENGTH + 1];
    struct node *next;
}
node;

// TODO: Choose number of buckets in hash table
const unsigned int N = 26;
int count = 0;

// Hash table
node *table[N];

// Returns true if word is in dictionary, else false
bool check(const char *word)
{
    node *cursor = malloc(sizeof(node));
    cursor->next = table[hash(word)]->next;
    while(cursor->next != NULL)
    {
        if(strcmp(cursor->word, word) == 0)
        {
            free(cursor);
            return true;
        }
        else
        {
            cursor = cursor->next;
        }
    }
    // TODO
    free(cursor);
    return false;
}

// Hashes word to a number
unsigned int hash(const char *word)
{
    // TODO: Improve this hash function
    char c = toupper(word[0]) - 65;
    return c;
}

// Loads dictionary into memory, returning true if successful, else false
bool load(const char *dictionary)
{

    for(int i = 0; i <= 25; i++)
    {
        table[i] = malloc(sizeof(node));
    }
    char word[LENGTH];
    FILE *file = fopen(dictionary, "r");
    if (file == NULL)
    {
        fclose(file);
        return false;
    }
    while(fscanf(file, "%s", word) != EOF)
    {
        fscanf(file, "%s", word);
        count++;
        if(table[hash(word)] == NULL)
        {
            node *n = malloc(sizeof(node));
            n->next = NULL;
            table[hash(word)]->next = *&n;
            strcpy(n->word, word);
        }
        else
        {
            node *n = malloc(sizeof(node));
            n->next = table[hash(word)]->next;
            table[hash(word)]->next = *&n;
            strcpy(n->word, word);
        }
    }
    fclose(file);


    // TODO
    return true;
}

// Returns number of words in dictionary if loaded, else 0 if not yet loaded
unsigned int size(void)
{
    // TODO
    return count;
}

// Unloads dictionary from memory, returning true if successful, else false
bool unload(void)
{
    node *cursor = malloc(sizeof(node));
    node *cursor2 = malloc(sizeof(node));
    for(int i = 0; i <= 25; i++)
    {
        cursor->next = table[i]->next;
        do
        {
            cursor2->next = cursor->next->next;
            if(cursor2->next == NULL)
            {
                free(cursor->next);
                break;
            }
            free(cursor->next);
            cursor->next = cursor2->next;
        }
        while(true);
    }
    free(cursor);
    free(cursor2);
    for(int i = 0; i <= 25; i++)
    {
        free(table[i]);
    }
    return true;

    // TODO
}

到目前为止，我尝试将表数组中的所有节点设置为空，这给了我一个分段错误，所以我改为在表数组中的每个节点上调用 malloc(sizeof(node)) 。我试过这个，因为我注意到它提到了未初始化的值。 Valgrind 还提到了一些关于无效的 free() 的事情，我不太明白。我对编码和制作数据结构还是很陌生，这也是我在蚂蚁编码论坛上发表的第一篇寻求任何形式帮助的帖子，因为此时我完全卡住了，所以我很抱歉这篇帖子（可能）格式错误，建议受欢迎的。谢谢。