chmod 0600 ~/.ssh/id_rsa 即可
Permissions 0644 for '/home/mengsen/.ssh/id_rsa' are too open.
It is required that your private key files are NOT accessible by others.
This private key will be ignored.
bad permissions: ignore key: /home/mengsen/.ssh/id_rsa
Permission denied (publickey).
fatal: 无法读取远程仓库。