今天重新编译了linux内核，增加了许多网络模块，然而在执行sudo apt-get update时，出现如下报警。
root@renesas:~# sudo apt-get update
Ign:1 https://mirrors.tuna.tsinghua.edu.cn/debian stretch InRelease
Ign:2 https://mirrors.tuna.tsinghua.edu.cn/debian stretch-updates InRelease
Ign:3 https://mirrors.tuna.tsinghua.edu.cn/debian stretch-backports InRelease
Ign:4 https://mirrors.tuna.tsinghua.edu.cn/debian-security stretch/updates InRelease
Err:5 https://mirrors.tuna.tsinghua.edu.cn/debian stretch Release
server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
Err:6 https://mirrors.tuna.tsinghua.edu.cn/debian stretch-updates Release
server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
0% [Working]server certificate verification failed. CAfile: /etc/ssl/certs/ca-ceErr:7 https://mirrors.tuna.tsinghua.edu.cn/debian stretch-backports Release
server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
Err:8 https://mirrors.tuna.tsinghua.edu.cn/debian-security stretch/updates Release
server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
Reading package lists... Done
E: The repository 'https://mirrors.tuna.tsinghua.edu.cn/debian stretch Release' does no longer have a Release file.
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.
E: The repository 'https://mirrors.tuna.tsinghua.edu.cn/debian stretch-updates Release' does no longer have a Release file.
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.
E: The repository 'https://mirrors.tuna.tsinghua.edu.cn/debian stretch-backports Release' does no longer have a Release file.
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.
E: The repository 'https://mirrors.tuna.tsinghua.edu.cn/debian-security stretch/updates Release' does no longer have a Release file.
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.
root@renesas:~# server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
网上找了好多办法，最后了解到是由于网站对证书是时间敏感的，需要改系统时间。于是修改linux系统为最新时间
date -s 2020/08/05
date -s 10:24:00
最后成功update