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Re: [PATCH] x86/kbuild: enable modversions for symbols exported from asm

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On Thu, Nov 24, 2016 at 06:20:26PM +1100, Nicholas Piggin wrote:
> But still, modversions is pretty complicated for what it gives us. It sends
> preprocessed C into a C parser that makes CRCs using type definitions of
> exported symbols, then turns those CRCs into a linker script which which is
> used to link the .o file with. What we get in return is a quite limited and
> symbol "versioning" system.
> 
> What if we ripped all that out and just attached an explicit version to
> each export, and incompatible changes require an increment?

How would that work for structures?  Would that be required for every
EXPORT_SYMBOL* somehow?

> Google tells me
> Linus is not a neutral bystander on the topic of symbol versioning, so I'm
> bracing for a robust response :) (actually I don't much care either way, I'm
> happy to put a couple of bandaids on it and keep it going)

There are tools that people are working on to make it more obvious where
API breaks happen by looking at the .o debug data instead of our crazy
current system (which is really better than nothing), perhaps we should
start using them instead?

See here for more details about this:
	https://kernel-recipes.org/en/2016/talks/would-an-abi-changes-visualization-tool-be-useful-to-linux-kernel-maintenance/

thanks,

greg k-h

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Re: BUG: 4.9-rc6 Still "no symbol version" on boot Philip Müller <philm@manjaro.org> - 2016-11-23 21:10 +0100
  Re: BUG: 4.9-rc6 Still "no symbol version" on boot Robert LeBlanc <robert@leblancnet.us> - 2016-11-23 21:20 +0100
    Re: BUG: 4.9-rc6 Still "no symbol version" on boot Philip Müller <philm@manjaro.org> - 2016-11-23 21:30 +0100
  Re: BUG: 4.9-rc6 Still "no symbol version" on boot Adam Borowski <kilobyte@angband.pl> - 2016-11-23 22:00 +0100
    Re: BUG: 4.9-rc6 Still "no symbol version" on boot Robert LeBlanc <robert@leblancnet.us> - 2016-11-23 22:10 +0100
    [PATCH] x86/kbuild: enable modversions for symbols exported from asm Adam Borowski <kilobyte@angband.pl> - 2016-11-23 23:10 +0100
      Re: [PATCH] x86/kbuild: enable modversions for symbols exported from  asm Philip Müller <philm@manjaro.org> - 2016-11-24 00:20 +0100
      Re: [PATCH] x86/kbuild: enable modversions for symbols exported from  asm Ingo Molnar <mingo@kernel.org> - 2016-11-24 06:10 +0100
        Re: [PATCH] x86/kbuild: enable modversions for symbols exported  from asm Nicholas Piggin <npiggin@gmail.com> - 2016-11-24 06:30 +0100
          Re: [PATCH] x86/kbuild: enable modversions for symbols exported from  asm Ingo Molnar <mingo@kernel.org> - 2016-11-24 07:10 +0100
            Re: [PATCH] x86/kbuild: enable modversions for symbols exported  from asm Nicholas Piggin <npiggin@gmail.com> - 2016-11-24 08:30 +0100
              Re: [PATCH] x86/kbuild: enable modversions for symbols exported from  asm Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-24 08:40 +0100
                Re: [PATCH] x86/kbuild: enable modversions for symbols exported  from asm Nicholas Piggin <npiggin@gmail.com> - 2016-11-24 09:00 +0100
                Re: [PATCH] x86/kbuild: enable modversions for symbols exported from  asm Michal Marek <mmarek@suse.com> - 2016-11-24 10:40 +0100
                Re: [PATCH] x86/kbuild: enable modversions for symbols exported  from asm Nicholas Piggin <npiggin@gmail.com> - 2016-11-24 11:10 +0100
                Re: [PATCH] x86/kbuild: enable modversions for symbols exported from  asm Michal Marek <mmarek@suse.com> - 2016-11-24 12:00 +0100
                Re: [PATCH] x86/kbuild: enable modversions for symbols exported from asm Arnd Bergmann <arnd@arndb.de> - 2016-11-24 10:50 +0100
                Re: [PATCH] x86/kbuild: enable modversions for symbols exported  from asm Nicholas Piggin <npiggin@gmail.com> - 2016-11-24 11:10 +0100
                Re: [PATCH] x86/kbuild: enable modversions for symbols exported from  asm Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-24 11:00 +0100
                Re: [PATCH] x86/kbuild: enable modversions for symbols exported  from asm Nicholas Piggin <npiggin@gmail.com> - 2016-11-24 11:40 +0100
                Re: [PATCH] x86/kbuild: enable modversions for symbols exported from  asm Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-11-24 16:30 +0100
                Re: [PATCH] x86/kbuild: enable modversions for symbols exported  from asm Nicholas Piggin <npiggin@gmail.com> - 2016-11-25 01:50 +0100
        Re: [PATCH] x86/kbuild: enable modversions for symbols exported from  asm Michal Marek <mmarek@suse.com> - 2016-11-24 10:30 +0100
      Regression: Re: [PATCH] x86/kbuild: enable modversions for symbols exported from asm Kalle Valo <kvalo@codeaurora.org> - 2016-11-24 12:50 +0100
    Re: BUG: 4.9-rc6 Still "no symbol version" on boot Philip Müller <philm@manjaro.org> - 2016-11-24 00:10 +0100

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