Home / ubuntu / Questions / 1254772
Accepted
Thijser
Asked: 2020-06-30 05:04:19 +0800 CST

cryptsetup: waiting for encrypted source device /swapfile, fstab empty

  • 772

On the bootscreen I get the message:

cryptsetup: waiting for encrypted source device /swapfile...

which then leaves me hanging for about 2 minutes followed by

Initramfs unpacking failed: Decoding failed.

I then get dropped to Initramfs.

This is on Ubuntu 20.04 with an encrypted home folder. I got the error after switching back to the nouveau driver in order to install cuda-10 (it was complaining about nvidia driver already being in use)

Other suggestions involve doing something with /etc/crypttab, but that file doesn't exist on my system. cat /etc/fstab also shows an empty file. Some reading suggests that in that case it would be using default settings but if so how does it know what disk should be used as a swapspace? Or is there something I can do with a live usb?

The output of mount is

none on / type rootfs (rw)
sysfs on /sys type sysfs (rw,nosuid, nodev, noexec, relatime)
proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)
udev on /dev type devtmpfs (rw,nosuid, noexec,relatime,size=32840428k,nr_inodes=8210107,mode=755)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
tmpfs on/run type tmpfs (rw,nosuid,nodev,noexec,relatime,size=6583428k,mode=755)

lsblk returns a non found error (this is in inframs so that might not work)

While mounting sdc1 on /mnt on a life usb I can get the following results: cat /mnt/etc/fstab looks like

# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
# / was on /dev/sdc1 during installation
UUID=5df229c0-be7c-43d7-b616-67ec15e2a6d3 /               ext4    errors=remount-ro 0       1
# /boot/efi was on /dev/nvme0n1p2 during installation
UUID=D23D-B0F6  /boot/efi       vfat    umask=0077      0       1
#/swapfile none            swap    sw              0       0
/dev/mapper/cryptswap1 none swap sw 0 0

. cat /mnt/etc/crypttab

looks like

# <target name> <source device>     <key file>  <options>
cryptswap1 /swapfile /dev/urandom swap,offset=1024,cipher=aes-xts-plain64

and lsblk -o name, type, uuid, label looks like

NAME        TYPE UUID                                 LABEL
loop0       loop                                      
loop1       loop                                      
loop2       loop                                      
loop3       loop                                      
loop4       loop                                      
loop5       loop                                      
sda         disk                                      
└─sda1      part 8C45-E3AC                            UBUNTU 20_0
sdb         disk                                      
├─sdb1      part                                      
└─sdb2      part                                      
sdc         disk                                      
└─sdc1      part 5df229c0-be7c-43d7-b616-67ec15e2a6d3 
nvme0n1     disk                                      
├─nvme0n1p1 part 60FC3C5FFC3C3220                     Recovery
├─nvme0n1p2 part D23D-B0F6                            
├─nvme0n1p3 part                                      
└─nvme0n1p4 part
encryption boot fstab cryptsetup 20.04

1 Answers

  1. Best Answer

    If I don't miss anything, everything seems fine with your configurations. However it might help to regenerate initramfs while disabling the /swap file encryption.

    Boot up the system using a live Ubuntu disk. mount these two partitions:

    $ sudo mount /dev/sdc1 /mnt
$ sudo mount /dev/nvme0n1p2 /mnt/boot/efi

    Open /mnt/etc/fstab and comment this line (add a # at the beginning):

    /dev/mapper/cryptswap1 none swap sw 0 0

    Open /mnt/etc/crypttab and comment this line (add a # at the beginning):

    cryptswap1 /swapfile /dev/urandom swap,offset=1024,cipher=aes-xts-plain64

    Now we have to chroot into system and regenerate the initramfs:

    $ sudo mount --bind /dev /mnt/dev
$ sudo chroot /mnt
# mount --type proc none /proc
# mount --type sysfs none /sys
# update-initramfs -k all -c

    It's all done. exit from chroot environment:

    # exit

    Un-mount the mounted partitions and reboot:

    $ sudo umount -R /mnt
$ sudo reboot

    Now you lost the encryption on /swap. However I think you didn't want it in the first place. You might try these instructions without editing /etc/fstab and /etc/crypttab. That might work too.

    • 2