问题: cudnn GPG error

Reading package lists... Done                                                                                                                                  
W: GPG error: file:/var/cudnn-local-repo-ubuntu2204-8.8.0.121  InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 91B24998B66125A0
E: The repository 'file:/var/cudnn-local-repo-ubuntu2204-8.8.0.121  InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

解决方案

找到 /var 目录下对应的 cudnn* 文件夹，然后执行如下命令

sudo cp /var/cudnn-local-repo-ubuntu2204-8.8.0.121/*.gpg /usr/share/keyrings/
sudo apt update
sudo apt upgrade

【参考】

W: GPG error: cudnn GPG key 错误