Bug 744076 – sys-kernel/gentoo-kernel-5.8.10[savedconfig] fails to compile: No rule to make target 'modules_prepare'

• Product: Gentoo Linux
• Status: RESOLVED FIXED

[Description Jaak Ristioja 2020-09-22 09:22:14 UTC]

#
# configuration written to .config
#
make[1]: Leaving directory '/var/tmp/portage/sys-kernel/gentoo-kernel-5.8.10/work/modprep'
make -j5 O=/var/tmp/portage/sys-kernel/gentoo-kernel-5.8.10/work/modprep V=1 HOSTCC=x86_64-pc-linux-gnu-gcc HOSTCXX=x86_64-pc-linux-gnu-g++ 'HOSTCFLAGS=-mtune=native -O2 -pipe' 'HOSTLDFLAGS=-Wl,-O1 -Wl,--as-needed' CROSS_COMPILE=x86_64-pc-linux-gnu- AS=x86_64-pc-linux-gnu-as CC=x86_64-pc-linux-gnu-gcc LD=x86_64-pc-linux-gnu-ld.bfd AR=x86_64-pc-linux-gnu-ar NM=x86_64-pc-linux-gnu-nm STRIP=: OBJCOPY=x86_64-pc-linux-gnu-objcopy OBJDUMP=x86_64-pc-linux-gnu-objdump ARCH=x86 modules_prepare 
make -C /var/tmp/portage/sys-kernel/gentoo-kernel-5.8.10/work/modprep -f /var/tmp/portage/sys-kernel/gentoo-kernel-5.8.10/work/linux-5.8/Makefile modules_prepare
make[1]: Entering directory '/var/tmp/portage/sys-kernel/gentoo-kernel-5.8.10/work/modprep'
make[1]: *** No rule to make target 'modules_prepare'.  Stop.
make[1]: Leaving directory '/var/tmp/portage/sys-kernel/gentoo-kernel-5.8.10/work/modprep'
make: *** [Makefile:185: __sub-make] Error 2

Maybe gentoo-kernel incorrectly assumes that all configurations have enabled support for loadable modules (CONFIG_MODULES)?

[Comment 1 Georgy Yakovlev 2020-09-22 10:55:33 UTC]

kernel-build.eclass ineed assumes that modules enabled.

[Comment 2 Ionen Wolkens 2020-09-22 12:47:02 UTC]

Had the same issue on my embedded system with no modules, ended up enabling it anyway but it wasn't ideal.

[Comment 3 Michał Górny 2020-10-02 06:47:23 UTC]

A patch (to kernel-build.eclass) would be helpful.

[Comment 4 Morteza 2021-10-15 07:15:32 UTC]

Is there any patch for this or at least a workaround I don't really need modules

[Comment 5 PF4Public 2021-11-15 17:06:29 UTC]

I use grep in my ebuilds to find out if modules are used:

grep "CONFIG_MODULES=y" .config >/dev/null
RETVAL=$?
if [ $RETVAL -ne 0 ]; then
	export DO_I_HAVE_MODULES=false
else
	export DO_I_HAVE_MODULES=true
fi

and:

if ${DO_I_HAVE_MODULES}; then
	emake modules ${xmakeopts}
fi

and finally:

if ${DO_I_HAVE_MODULES}; then
	emake modules_install ${xmakeopts} INSTALL_MOD_PATH="${D}";
fi

Is it a good solution for kernel-build.eclass?

[Comment 6 Nowa Ammerlaan 2024-08-30 20:13:48 UTC]

CONFIG_MODULES=n works fine nowadays[1]. Not sure what changed but it seems like the behaviour of the kernel build system is different now because running modules_prepare  when CONFIG_MODULES=n silently does nothing instead of causing a 'target does not exist' error.

[1] https://gitweb.gentoo.org/repo/gentoo.git/commit/eclass/kernel-build.eclass?id=e19b3318171fe5482417c00e0ff198091080944b