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Re: Cannot compile kernel: problem with EXPORT_SYMBOL and EXPORT_SYMBOL_GPL symbols



On Sun, 2013-02-17 at 15:33 +0100, Dmitry Katsubo wrote:
> On 15.02.2013 20:40, Ben Hutchings wrote:
> >> -CONFIG_NR_CPUS=32
> >> +CONFIG_NR_CPUS=2
> > 
> > Why?
> 
> Well, it turned out that 686-pae kernel from repository does not boot on
> my PC: kernel hangs during initialization. 486 is booting OK.
> Recompilation for the native CPU was the last measure. If I am already
> playing with recompilation, why not to reduce the number of CPUs (as to
> help, that is saving 30 * 8Kb = 240Kb).
>
> > Yes, because you changed the kernel module ABI without changing
> > the binary package name.
> 
> Interesting is that I have also changed few other options:
> 
> CONFIG_X86_GENERIC=n
> CONFIG_MICROCODE_INTEL=n
> CONFIG_MICROCODE_AMD=n
> CONFIG_PREEMPT_NONE=y
> 
> and it looks like this did not change ABI. That puzzled me.

Changing CONFIG_NR_CPUS changes the size of objects in memory, which
modules may depend on, whereas the others don't.  (But turning off
CONFIG_X86_GENERIC probably ought to be considered as changing ABI.)

> > If you really think it's worth doing this (and you really want to
> > use the official package as a basic, rather than 'make deb-pkg'), you
> > have two basic options:
> > 
> > 1. Add a distinguishing string after the ABI number in
> > debian/config/defines.  Please do not just change it to 5 as this
> > could be confused with an official package name.
> >
> > 2. Define a new 'flavour' with this configuration change.  Each
> > flavour has its own ABI.  You'll need to edit
> > debian/config/i386/defines to add the flavour name and define
> > it to use an extra configuration file which overrides
> > CONFIG_NR_CPUS.
> 
> I have changed the string to "4fix" and I have overwritten the
> configuration with custom one:
> 
> $ cp ../myconfig debian/config/kernelarch-x86/config-arch-32
> 
> After that it worked smoothly. Thanks!

Please can you send the complete configuration file and the contents of
/proc/cpuinfo?

Ben.

-- 
Ben Hutchings
Experience is what causes a person to make new mistakes instead of old ones.

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