Re: [regression ?] kbuild: fix building bzImage with CONFIG_TRIM_UNUSED_KSYMS enabled

From: Nicolas Pitre
Date: Fri Dec 09 2016 - 13:08:07 EST


On Fri, 9 Dec 2016, Sergey Senozhatsky wrote:

> On (12/08/16 22:40), Nicolas Pitre wrote:
> > > > after 53924022d8a ("kbuild: fix building bzImage withCONFIG_TRIM_UNUSED_KSYMS
> > > > enabled") all of my build scripts build the kernel without the modules.
> > >
> > > [..]
> > > > +# For the kernel to actually contain only the needed exported symbols,
> > > > +# we have to build modules as well to determine what those symbols are.
> > > > +# (this can be evaluated only once include/config/auto.conf has been included)
> > > ^^^^^
> > >
> > > ah, the config. so the patch is wrong.
> >
> > Furthermore, the export statement exports the variable not its value.
> > Even if the value is changed afterwards, referencing the exported
> > variable will see the new value.
>
> yeah, need to investigate more. for some, unknown, reason
> modules_install gives me empty lib/modules.
>
> the build script (archlinux) builds it in 2 steps: build() and package().
> basically:
>
> build:
> make -j4 > build_log 2>&1
>
> package:
> make -j4 INSTALL_MOD_PATH="${pkgdir}" modules_install >> build_log 2>&1
>

Weird. I basically did that and I can't reproduce your problem.

> makepkg
> ls -la
> pkg/kernel-4.9.0-rc8-dbg-00085-ga37102d-dirty/lib/modules/4.9.0-rc8-dbg-00085-ga37102d-dirty/kernel/
> drwxr-xr-x 2 ss ss 4096 Dec 9 13:51 .
> drwxr-xr-x 3 ss ss 4096 Dec 9 13:51 ..
>
>
> git revert 865563924022d8
> makepkg
> ls -la pkg/kernel-4.9.0-rc8-dbg-00086-g7ea3980-dirty/lib/modules/4.9.0-rc8-dbg-00086-g7ea3980-dirty/kernel/
> drwxr-xr-x 10 ss ss 4096 Dec 9 13:55 .
> drwxr-xr-x 3 ss ss 4096 Dec 9 13:55 ..
> drwxr-xr-x 3 ss ss 4096 Dec 9 13:55 arch
> drwxr-xr-x 2 ss ss 4096 Dec 9 13:55 crypto
> drwxr-xr-x 14 ss ss 4096 Dec 9 13:55 drivers
> drwxr-xr-x 4 ss ss 4096 Dec 9 13:55 fs
> drwxr-xr-x 4 ss ss 4096 Dec 9 13:55 lib
> drwxr-xr-x 2 ss ss 4096 Dec 9 13:55 mm
> drwxr-xr-x 3 ss ss 4096 Dec 9 13:55 net
> drwxr-xr-x 5 ss ss 4096 Dec 9 13:55 sound

You must have CONFIG_TRIM_UNUSED_KSYMS=y in your .config, right?

What if you set it to n instead without reverting 865563924022d8. Do you
still have the same issue?

In any case, could you give me your .config to help me reproduce?


Nicolas