Why won't MariaDB start after upgrade (NO_NEW_PRIVILEGES)

With help from #debian-next I found out the problem was probably in the digitalocean custom kernel.

Upon checking it turned out I was using a not very recent kernel – 3.2.0-4, but after selecting a more recent version from the web interface and rebooting it works OK.

I can't upgrade the kernel (this is a vps).

I have found a solution :

edit /lib/systemd/system/mariadb.service

change PrivateDevices=true to PrivateDevices=false

Run systemctl daemon-reload

and systemctl start mysql

I had this same problem with Debian 9.1 and MariaDB 10.1.26-MariaDB-0+deb9u1. Seems it was also related to the kernel version. Updating kernel from 3.2.50 to 4.9.0-3-amd64 fixed it.