After upgrading from Ubuntu 17.10 to Ubuntu 18.04, and rebooting, the GNOME Display Manager (gdm) went into a restart loop. No promised speed gains. Instead, I got an unusable desktop.
nvidia crash gdm intel ubuntu
Today we ran into a dovecot/imap crash on a Xenial box. The Dovecot in question was the patched dovecot-2.2.22.
debug dovecot crash roundcube