/usr/bin/sudo must be owned by uid 0 and have the setuid bit set when solving ordinary user sudo

One: This problem is caused by the previous misoperation using the sudo chmod -R 777 /usr command to modify the owner of the usr file;

Two: It is said on the Internet that you need to enter the recovery mode, which is not required after your own test;

Three: Steps (just log in to normal mode)

1.su - root switch to root user;

2. Execute chown root:root /usr/bin/sudo

3. Execute chmod 4755 /usr/bin/sudo

4. After reboot, ordinary users can use sudo again;