Re: [PATCH] Narrow Linux symbol CRCs to 32 bits

[Dodji Seketeli <dodji@seketeli.org>]

Hello,

[...]

On Fri, 28 Oct 2022 at 16:13, Dodji Seketeli <dodji@seketeli.org> wrote:

>> The changes look good to me.  Do you want me to apply it right now, or
>> do you prefer to send a subsequent patch that addresses the new way how
>> CRCs are emitted in kernel object?

Giuliano Procida <gprocida@google.com> a écrit:

> I'm happy for the change to go in. However, the commit message text
> should be updated. I would make it:
>
> --
>
> MODVERSIONS CRCs are 32-bit hashes of strings representing C type
> elements or typed symbols. The hashes are calculated using a 32-bit CRC,
> hence the name. The kernel module loading code (implicitly) truncates
> any provided CRC value to 32 bits before comparing it with anything.
>
> When support was added to libabigail, values up to 64 bits wide were
> supported. This change narrows libabigail's concept of Linux CRC to 32
> bits. No tests are affected.
>
> --
>
> I'm not sure when we'll get around to updating the symtab reader. It'll
> probably not be done by me. As I understand things, there are
> something like 3 or 4 different encodings of CRCs depending on the
> kernel version and architecture (and that's ignoring endianness issues).
>
> Matthias has even suggested it might be better (more reliable) just reading
> CRCs from Modules.symvers instead. However, that would require more
> integration into build scripts etc.

This felt through the cracks on my end, sorry about that.

I have just applied the v2 of the patch that you've sent 5 days ago.

Thank you for that.

[...]

Cheers,

-- 
		Dodji