Comment 15 for bug 1453738

the important part in journal:

mai 27 07:44:51 user-VirtualBox systemd[1]: Starting Cryptography Setup for sda5_crypt...
mai 27 07:44:51 user-VirtualBox systemd-cryptsetup[427]: Volume sda5_crypt already active.
mai 27 07:44:51 user-VirtualBox systemd[1]: Started Cryptography Setup for sda5_crypt.
mai 27 07:44:51 user-VirtualBox systemd[1]: Found device /dev/mapper/ubuntu--vg-swap_1.
mai 27 07:44:51 user-VirtualBox systemd[1]: Found device /dev/disk/by-uuid/f636d7ef-9405-482d-a90a-5ba67026fcfb.
mai 27 07:44:51 user-VirtualBox systemd[1]: Activating swap /dev/mapper/ubuntu--vg-swap_1...
mai 27 07:44:51 user-VirtualBox kernel: Adding 1572860k swap on /dev/mapper/ubuntu--vg-swap_1. Priority:-1 extents:1 across:1572860k FS
mai 27 07:44:51 user-VirtualBox systemd[1]: Activated swap /dev/mapper/ubuntu--vg-swap_1.
...
mai 27 07:44:53 user-VirtualBox systemd[1]: Starting Cryptography Setup for cryptswap1...
mai 27 07:44:53 user-VirtualBox systemd-cryptsetup[462]: Set cipher aes, mode xts-plain64, key size 256 bits for device /dev/disk/by-uuid/f636d7ef-9405-482d-a90a-5ba67026fcfb.
mai 27 07:44:53 user-VirtualBox systemd-cryptsetup[462]: Failed to activate with key file '/dev/urandom': Device or resource busy