Dependency issues when building an external kernel module

For Developers
1

I'm building an out of tree kernel module for use in openwrt.

The module compiles with out errors but the build fails due to dependencies.

If i do in the module makefile:

...
 DEPENDS:=+kmod-nf-conntrack
  KCONFIG:=CONFIG_NET_SCH_ARL=y
  FILES:= \
        $(PKG_BUILD_DIR)/sch_arl.ko

  AUTOLOAD:=$(call AutoLoad,75,sch_arl)
  DEPENDS:=
endef

I'll get:

Package kmod-sched-arl is missing dependencies for the following libraries:
nf_conntrack.ko

and the build fails. I can add nf_conntract.ko (plus a couple of it's dependencies)
ala

  FILES:= \
        $(PKG_BUILD_DIR)/sch_arl.ko \
       $(LINUX_DIR)/net/netfilter/nf_conntrack.ko \
       $(LINUX_DIR)/net/ipv4/netfilter/nf_defrag_ipv4.ko \
       $(LINUX_DIR)/net/ipv6/netfilter/nf_defrag_ipv6.ko

I can build the package on it's own, but if I try to do a build with my kmod built in, the build will fail with bunch of errors like:

...
        But that file is already provided by package  * kmod-sched-arl
 * opkg_install_cmd: Cannot install package kmod-nf-conntrack6.
 * check_data_file_clashes: Package kmod-nf-conntrack wants to install file /home/sn/openwrt/\
build_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/root-ipq806x/lib/modules/5.10.104/nf_con\
ntrack.ko
        But that file is already provided by package  * kmod-sched-arl
 * check_data_file_clashes: Package kmod-nf-conntrack wants to install file /home/sn/openwrt/\
build_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/root-ipq806x/lib/modules/5.10.104/nf_def\
rag_ipv4.ko
        But that file is already provided by package  * kmod-sched-arl
 * check_data_file_clashes: Package kmod-nf-conntrack wants to install file /home/sn/openwrt/\
build_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/root-ipq806x/lib/modules/5.10.104/nf_def\
rag_ipv6.ko
...

plus some others I did not expect.

What is the proper way to handle out of tree kmod dependencies?

The openwrt package guide is helpful, but a bit sparse on details. Note for this out of tree kernel module to function, I am patching in tree include files, a Kconfig, and one *.c file.

EDIT: i just noticed that i have an extra DEPENDS:= - I'll try removing that.

2

Make sure you Require */y the Kmod package,rather than {M}, or it won't include it in the image directly. It's a bit counter-intuitive, at least for me, because you've got to Require to Include something that ultimately is modularized.

3

If I don't make silly errors like leaving an empty DEPENDS:= statements in my Makefile, then every builds fine. Who would have thought.

But thankyou @Grommish for taking a look.

EDIT I don't need the additional nf_conntract.ko or others in case someone else finds their way here.

1 Like
4

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