Re: [PATCH 3/39] NLKD - early/late CPU up/down notification

From: Greg KH (greg_at_kroah.com)
Date: 11/11/05

  • Next message: Paulo da Silva: "Re: Accessing file mapped data inside the kernel"
    Date:	Thu, 10 Nov 2005 15:01:26 -0800
    To: Jan Beulich <JBeulich@novell.com>
    
    

    On Thu, Nov 10, 2005 at 08:41:32AM +0100, Jan Beulich wrote:
    > >>> Greg KH <greg@kroah.com> 09.11.05 18:19:19 >>>
    > >On Wed, Nov 09, 2005 at 06:09:27PM +0100, Jan Beulich wrote:
    > >> >>> Greg KH <greg@kroah.com> 09.11.05 17:45:44 >>>
    > >> >#ifdef in the .h file is not needed. Please fix your email client
    > to
    > >> >send patches properly.
    > >>
    > >> It's not needed, sure, but by having it there I just wanted to make
    > >> clear that this is something that never can be called from a module
    > >> (after all, why should one find out at modpost time (and maybe even
    > miss
    > >> the message since there are so many past eventual symbol resolution
    > >> warnings) when one can already at compile time.
    > >
    > >If it isn't present, and you do a build, you will still get the error
    > at
    > >build time, just during a different part of it. Adding #ifdef just
    > to
    > >move the error to a different part of the build isn't needed.
    > Remember,
    > >we want to not use #ifdef at all if we can ever help it.
    >
    > I understand that. But you don't see my point, so I'll try to explain
    > the background: When discovering the reason for the kallsyms change
    > (also posted with the other NLKD patches) not functioning with
    > CONFIG_MODVERSIONS and binutils between 2.16.90 and 2.16.91.0.3 I
    > realized that the warning messages from the modpost build stage are very
    > easy to overlook (in fact, all reporters of the problem overlooked them
    > as well as I did on the first build attempting to reproduce the
    > problem).

    When you try to load the module, you will get the error again, right in
    your kernel/system log, which explicitly shows that you had a problem.

    > This basically means these messages are almost useless, and
    > detection of the problem will likely be deferred to the first attempt to
    > load an offending module (which, as in the case named, may lead to an
    > unusable kernel). Hence, at least until this build problem gets
    > addressed I continue to believe that adding the preprocessor conditional
    > is the better way of dealing with potential issues. Sure I know that
    > hundreds of other symbols possibly causing the same problem aren't
    > protected...

    Don't try to do things to fix your prior problems in your patch, with
    changes today so that you don't do it again in the future :)

    The build process properly notifies the builder of the problem, if they
    ignore it, there's really nothing more we can do about it, right?

    thanks,

    greg k-h
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  • Next message: Paulo da Silva: "Re: Accessing file mapped data inside the kernel"

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