Re: Building old systems

[Valery Ushakov <uwe%stderr.spb.ru@localhost>]

On Wed, Apr 19, 2023 at 16:34:19 -0600, Brook Milligan wrote:

> I am trying to build an old kernel with build.sh on a recent
> (9.99.108) amd64 system.  However, compiling nbmake fails
> immediately with errors like
>
> 	/usr/bin/ld: buf.o:(.bss+0x0): multiple definition of `debug_file'; arch.o:(.bss+0x0): first defined here 
>
> Unless I am doing something silly, it clearly is not possible for a
> current system to build old tools and kernels at arbitrary points in
> time.
>
> What is the best strategy for building old kernels to, for example,
> bisect the code?

It might be better to use corresponding older tools to build older
kernels.  Modern gcc switched to -fno-common by default, so if you
want to compile an older kernel that has multiple variable definitions
you will need to arrange for -fcommon option to be used.

-uwe