ERROR: Kernel configuration is invalid. include/generated/autoconf.h or include/config/auto.conf are missing.

[shemgp]

I'm unable to build dkms packages since it errors out with:

make ARCH=x86_64 CROSS_COMPILE= -C /lib/modules/5.10.0-14-generic/build M=/var/lib/dkms/rtl88x2bu/git/build modules
make[1]: Entering directory '/usr/src/linux-headers-5.10.0-14-generic'

  ERROR: Kernel configuration is invalid.
         include/generated/autoconf.h or include/config/auto.conf are missing.
         Run 'make oldconfig && make prepare' on kernel src to fix it.

make[1]: *** [Makefile:745: include/config/auto.conf] Error 1
make[1]: Leaving directory '/usr/src/linux-headers-5.10.0-14-generic'
make: *** [Makefile:2378: modules] Error 2

So I run:

make oldconfig && make prepare

in /usr/src/linux-headers-5.10.0-14-generic

and it errors out with:

make[1]: *** No rule to make target 'arch/x86/tools/relocs_32.c', needed by 'arch/x86/tools/relocs_32.o'. Stop.
make: *** [arch/x86/Makefile:214: archscripts] Error 2

Thanks for your help!

ProblemType: Bug
DistroRelease: Ubuntu 21.04
ProcVersionSignature: Ubuntu 5.10.0-14.15-generic 5.10.11
Uname: Linux 5.10.0-14-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu59
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: shemgp 6098 F.... pulseaudio
 /dev/snd/controlC1: shemgp 6098 F.... pulseaudio
CasperMD5CheckResult: unknown
CurrentDesktop: ubuntu:GNOME
Date: Tue Feb 23 00:59:55 2021
EcryptfsInUse: Yes
InstallationDate: Installed on 2015-09-28 (1974 days ago)
InstallationMedia: Ubuntu 15.04 "Vivid Vervet" - Release amd64 (20150422)
MachineType: LENOVO 34361A0
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.10.0-14-generic root=UUID=da81a856-84d5-4ca7-8c0a-4f20006730bc ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-5.10.0-14-generic N/A
 linux-backports-modules-5.10.0-14-generic N/A
 linux-firmware 1.194
SourcePackage: linux
StagingDrivers: ashmem_linux
UpgradeStatus: Upgraded to hirsute on 2021-02-16 (6 days ago)
dmi.bios.date: 09/25/2019
dmi.bios.release: 2.75
dmi.bios.vendor: LENOVO
dmi.bios.version: GCETB5WW (2.75 )
dmi.board.asset.tag: Not Available
dmi.board.name: 34361A0
dmi.board.vendor: LENOVO
dmi.board.version: Not Defined
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.ec.firmware.release: 1.15
dmi.modalias: dmi:bvnLENOVO:bvrGCETB5WW(2.75):bd09/25/2019:br2.75:efr1.15:svnLENOVO:pn34361A0:pvrThinkPadX220:rvnLENOVO:rn34361A0:rvrNotDefined:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.family: ThinkPad X220
dmi.product.name: 34361A0
dmi.product.sku: LENOVO_MT_3436
dmi.product.version: ThinkPad X220
dmi.sys.vendor: LENOVO

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.

[trombka (trombka)]

I had a similar issue after upgrading to 21.04.
Package linux-headers-<version> silently failed to build these config files due to lack of packages flex and bison.

sudo apt install flex bison
sudo dpkg-reconfigure linux-headers-<version>

solved the problem, although the build still fails, but in a later stage.