在C中创建链表，获取分段错误

typedef struct Node {
    int data;
    struct Node* next;
} Node;

Node* head = NULL;

void insert(int data) {
    Node* newNode = (Node*)malloc(sizeof(Node));
    newNode->data = data;
    newNode->next = NULL;

    if (head == NULL) {
        head = newNode;
    } else {
        Node* current = head;
        while (current->next != NULL) {
            current = current->next;
        }
        current->next = newNode;
    }
}

int main() {
    insert(1);
    insert(2);
    insert(3);
    // 可以继续插入更多节点

    // 打印链表中的数据
    Node* current = head;
    while (current != NULL) {
        printf("%d ", current->data);
        current = current->next;
    }

    return 0;
}