Re: sections mismatch detection

From: Sam Ravnborg
Date: Wed Jan 06 2010 - 05:48:33 EST


On Wed, Jan 06, 2010 at 12:11:23PM +0200, Artem Bityutskiy wrote:
> Hi,
>
> I wonder is it good time to enable DEBUG_SECTION_MISMATCH by default
> now? I mean, remove the following from lib/Kconfig.debug:
>
> config DEBUG_SECTION_MISMATCH
> bool "Enable full Section mismatch analysis"
> depends on UNDEFINED
> # This option is on purpose disabled for now.
> # It will be enabled when we are down to a resonable number
> # of section mismatch warnings (< 10 for an allyesconfig build)
>
> Just spotted this, and decided to remind.

My original criteria for enabling this was that we had a warnign free build
for all*config on x86 and a few other architectures.
While focusing on this I never reached this goal as I usually ended
up with some problems related to CPU hotplug.
I dunno how close we are today at the "zero warning" target.

When people implemented CPU hotplug they started to use __cpuinit
not only for code used during init time but also for code used
solely for CPU hotplugging. That made it difficult to solve
all the corner cases.
Because __cpu* annotation was used outside the original scope
I suggested to remove them from the checks but alas got no response.
Running out of time I gave up.

But I can see a steady flow of section mismatch fixes so I think the
situation looks better these days.

As the kbuild maintainer traditionally has been a central person
in this respect (due to the functionality in modpost),
I would like Michal to support this if we decide to enable the option.

Sam
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