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From: Milan Broz <gmazyland@gmail.com>
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Date: Thu, 18 Jul 2019 11:50:51 +0200
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Subject: Re: [dm-crypt] veritysetup forward error correction failure
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To: Tom Eccles <tom.eccles@codethink.co.uk>, dm-crypt@saout.de
Cc: richardmaw@codethink.co.uk

On 18/07/2019 11:10, Tom Eccles wrote:
> tomeccles@debian-kernel-builder:~$ uname -a
> Linux debian-kernel-builder 4.19.37-verity #6 SMP Wed Jul 17 11:47:38 BST
> 2019 x86_64 GNU/Linux
> tomeccles@debian-kernel-builder:~$ /usr/sbin/veritysetup --version
> veritysetup 2.1.0
> 
> I can also reproduce the issue using veritysetup 2.2.0-rc1.

Thanks, the best would be to create an issue for cryptsetup project
https://gitlab.com/cryptsetup/cryptsetup/issues
(if it is a kernel bug we report it there later)

I will need some images (or a script to create them) to reproduce it though.

...

> Also, I tried adding some prints to veritysetup and the kernel, and on the
> face of it, the reed-solomon state (struct rs in veritysetup) seems the
> same.

AFAIK the kernel and our code was based on the same libfec code,
so I am quite interested to find out what is the difference here.

(It can take some time though, the userspace FEC image verification was
implemented by my student that already disappeared from the project :)

Thanks,
Milan