Since some weeks ssh asks me to Enter passphrase for key '[home directory]/.ssh/id_rsa' without any changes to the system. I may have installed updates, but I can't make a connection to a specific one, also not after going through /var/log/apt/history.log.
Invoking gpg-agent which I recall is somehow related to storing such passwords prints gpg-agent[24068]: no gpg-agent running in this session to terminal.
I'm using Unity and see the same issue when using GNOME shell.
After removing a stale ~/.gnupg/gnupg_spawn_agent_sentinel.lock I could fix and issue where I experienced a ~60 seconds freeze of the screen between login and displaying of the desktop for both Unity and GNOME shell and after every login as well as blocking of email sending in thunderbird because the add-on Enigmail was launching /usr/bin/gpg2 --charset utf-8 --display-charset utf-8 --use-agent --batch --no-tty --status-fd 2 --with-fingerprint --fixed-list-mode --with-colons --list-secret-keys which (run in a terminal) permanently printed gpg: waiting for lock (held by 28158) .... So, there might be more issues regarding stale locks.
I'm using Ubuntu 17.10.
