我仍然无法理解为什么这里仍然存在内存泄漏，因为strdup（这是错误的说法），我确保在删除节点之前释放了strdup的所有分配的内存，并在程序结束时释放了所有节点。我错过了什么？
下面是我写的代码：

struct background_processes *head = NULL;

struct background_processes {
    int pid;
    char *cmd_name;
    struct background_processes *next;
};

// Add a background process to the Background processes LinkedList
void add_background_process(int pid, char *name) {
    if (head == NULL) {
        head = malloc(sizeof(struct background_processes));
        if (head == NULL) {
            exit(EXIT_FAILURE);
        }
        head->pid = pid;
        head->cmd_name = strdup(name);
        head->next = NULL;
    } else {
        struct background_processes *current = head;
        while (current->next != NULL) {
            current = current->next;
        }
        current->next = malloc(sizeof(struct background_processes));
        if (current->next == NULL)
            exit(EXIT_FAILURE);
        current->next->pid = pid;
        current->next->cmd_name = strdup(name);
        current->next->next = NULL;
    }
}

// Remove a background process from the Background processes LinkedList
void remove_background_process(int pid) {
    struct background_processes *current = head;
    struct background_processes *prev = NULL;
    while (current != NULL) {
        /* If the process is running */
        if (pid == current->pid) {
            if (current == head) {
                head = head->next;
                free(current->cmd_name);
                free(current);
                current = head;
            } else {
                prev->next = current->next;
                free(current->cmd_name);
                free(current);
                current = prev->next;
            }
        } else {
            prev = current;
            current = current->next;
        }
    }
}

void free_linkedlist() {
    struct background_processes *current = head;
    struct background_processes *after;

    while (current != NULL) {
        after = current->next;
        free(current->cmd_name);
        free(current);
        current = after;
    }
}

int main() {
    // Some code 

    while (1) {
        // Some other code
        
        execute_pipeline(l);
    }
    // Freeing all allocated memory
    free_linkedlist();
}

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我很感激你的帮助。谢谢！