bug#24028: Linux-libre kernel does not build deterministically

[zimoun]

Hi,

On Fri, 09 Oct 2020 at 17:17, Maxim Cournoyer <maxim.cournoyer@gmail.com> wrote:
> ludo@gnu.org (Ludovic Courtès) writes:
>
>> As of version 4.6.4, Linux-libre does not build reproducibly:
>>
>> $ guix challenge linux-libre
>> /gnu/store/wkdnd1dcgljr0jxmd3li8j0qsr2zwrci-linux-libre-4.6.4 contents 
>> differ:
>>   local hash: 1py214sd42qcq8l429m4zf4aibp8rl68kpkrzqi1nn65vnbxsx11
>>   
>> https://hydra.gnu.org/nar/wkdnd1dcgljr0jxmd3li8j0qsr2zwrci-linux-libre-4.6.4:
>> 19hsdsjy5i9nfc1g28s074znzimzhylgkdpwz435j301sn9pxxp9
>> $ wget -q -O -
>> https://hydra.gnu.org/nar/wkdnd1dcgljr0jxmd3li8j0qsr2zwrci-linux-libre-4.6.4
>> | bunzip2 | guix archive -x t
>> $ diff -ur --no-dereference 
>> /gnu/store/wkdnd1dcgljr0jxmd3li8j0qsr2zwrci-linux-libre-4.6.4 /tmp/t
>> Binary files 
>> /gnu/store/wkdnd1dcgljr0jxmd3li8j0qsr2zwrci-linux-libre-4.6.4/bzImage and 
>> /tmp/t/bzImage differ
>>
>> Apparently people are working on it:
>> <https://wiki.debian.org/SameKernel>.
>
> I just tested with linux-libre 5.8.10, and it still suffers from
> reproducibility problems, but only for one file:
>
> diff -r 
> /gnu/store/jc1dydmax5sdfljpi5mq5dhq9wdr92xy-linux-libre-5.8.10{,-check}
> Binary files 
> /gnu/store/jc1dydmax5sdfljpi5mq5dhq9wdr92xy-linux-libre-5.8.10/bzImage and 
> /gnu/store/jc1dydmax5sdfljpi5mq5dhq9wdr92xy-linux-libre-5.8.10-check/bzImage 
> differ

Still the same issue with 5.13.15.

diff -r --no-dereference 
/gnu/store/y9r7physjpa23znb7r6rg38wpmxrkp0s-linux-libre-5.13.15{,-check}
Binary files 
/gnu/store/y9r7physjpa23znb7r6rg38wpmxrkp0s-linux-libre-5.13.15/bzImage and 
/gnu/store/y9r7physjpa23znb7r6rg38wpmxrkp0s-linux-libre-5.13.15-check/bzImage 
differ


All the best,
simon