Warning message about cryptsetup during boot

Asked by Mathieu Dubois on 2020-10-23

I have noticed that since upgrade to 20.04.1 (from 18.04), a warning message appears during boot: "cryptsetup: WARNING: Option 'size' missing in crypttab for plain dm-crypt mapping cryptswap1. Please read /usr/share/doc/cryptsetup-initramfs/README.initramfs.gz and add the correct 'size' option to your crypttab(5).".

AFAICT, there is no problem however. I use ecryptfs to encrypt my home directory but I don't think it's related (since the message are related to swap). This message used to appear during updates but I never paid attention to it.

Others have reported the problem (https://askubuntu.com/questions/1109463). It seems that before 20.04, just editing /etc/crypttab was enough but some users say that they need to manually regenerate the initramfs image after each update.

For now, I'm not sure it's a bug. Any advice ? Should I edit the /etc/crypttab ? With which value ? Do I need to regenerate the initramfs image after each update (in which cas it's probably a bug) ?

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Bernard Stafford (bernard010) said : #2

I advise filling a Bug Report. Terminal: ubuntu-bug linux
This starts Apport and will automatically generate info added to your bug report.
Did you open and read the file?
I am enclosing the Manpage for cryptsetup

It might be asking for the number of 512 bite sectors of the device. Due to it is an Open Action.

Bernard Stafford (bernard010) said : #3

Type "O" 512 byte sectors

Thanks for your answer and sorry for the long delay.

My laptop boots without problem. AFAICT the medium.com link you send describes the same workaround than https://askubuntu.com/questions/1109463 which has to be redone after every kernel upgrade.

I don't understand the end of your first comment and your second comment. I guess you suggest to read the man page and the FAQ but I don't understand most of their content.

Anyway, I have opened a bug report (see Bug #1903920).

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