Some Centos 7 BTFs removed from the archive between September 2022 and now (July 2024)

[nelljerram]

Thanks for the btfhub archive! I've been reviewing the loss of some Centos 7 files since September 2022, namely:

/btf/centos/7/x86_64/3.10.0-123.1.2.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-123.13.1.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-123.13.2.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-123.20.1.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-123.4.2.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-123.4.4.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-123.6.3.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-123.8.1.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-123.9.2.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-123.9.3.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-123.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-229.1.2.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-229.11.1.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-229.14.1.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-229.20.1.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-229.4.2.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-229.7.2.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-229.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-327.10.1.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-327.13.1.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-327.18.2.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-327.22.2.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-327.28.2.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-327.28.3.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-327.3.1.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-327.36.1.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-327.36.2.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-327.36.3.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-327.4.4.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-327.4.5.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-327.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-514.10.2.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-514.16.1.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-514.2.2.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-514.21.1.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-514.21.2.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-514.26.1.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-514.26.2.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-514.6.1.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-514.6.2.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-514.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-693.1.1.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-693.11.1.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-693.11.6.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-693.17.1.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-693.2.1.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-693.2.2.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-693.21.1.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-693.5.2.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-693.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-862.11.6.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-862.14.4.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-862.2.3.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-862.3.2.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-862.3.3.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-862.6.3.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-862.9.1.el7.x86_64.btf
/btf/centos/7/x86_64/3.10.0-862.el7.x86_64.btf

I am not 100% sure, but I believe all of these were removed as a result of "83e61d7 * workflow: enable centos BTF updates". The commit is not very well documented, but based on the code changes it looks like:

• They were added to btfhub as "centos/7", but had actually been built from centos 8 packages.
• That commit also updates a minimum kernel version parameter from "2.10.0-957" to "3.10.0-957".

It's a bit weird because there were several corrections in that commit were the previous code had numbers that were all +/- 1 from what they should be. It's not clear if the minimum kernel version change was one of those, or for a different reason.

Would you reviewing and letting me know your thoughts on whether it was the right thing for these BTFs to be removed from the archive?

[geyslan]

@rafaeldtinoco I know it's been a while since 83e61d7, but do you remember the reasons? Cheers!

[rafaeldtinoco]

Likely due to the kernel being too old and not supporting CO-RE (so having BTFs made no sense). Also, they were likely added "by accident" because of automation during initial development IIRC. I could be wrong and yes, the btfhub commit messages were not very detailed unfortunately.

[nelljerram]

Thank you for reviewing this. Please feel free to close the issue.