must have current kernel's headers to build kernel version for module

[Scott Moser]

$ sudo dkms ldtarball --archive=madwifi-0.9.4+4178-source-only.dkms.tar.gz
$ dpkg-query --show | grep linux.*headers
linux-headers-3.2.0-14 3.2.0-14.23
linux-headers-3.2.0-14-generic 3.2.0-14.23
linux-headers-3.2.0-14-virtual 3.2.0-14.23
linux-headers-generic 3.2.0.14.14
$ uname -r
3.2.0-12-virtual

$ sudo dkms -k 3.2.0-14-virtual build madwifi -v 0.9.4+4178
Kernel preparation unnecessary for this kernel. Skipping...
Building module:
cleaning build area....(bad exit status: 2)
make KERNELRELEASE=3.2.0-14-virtual modules KERNDIR=/lib/modules/3.2.0-14-virtual....(bad exit status: 2)
ERROR (dkms apport): binary package for madwifi: 0.9.4+4178 not found
Error! Bad return status for module build on kernel: 3.2.0-14-virtual (x86_64)
Consult /var/lib/dkms/madwifi/0.9.4+4178/build/make.log for more information.

$ cat /var/lib/dkms/madwifi/0.9.4+4178/build/make.log
DKMS make.log for madwifi-0.9.4+4178 for kernel 3.2.0-14-virtual (x86_64)
Tue Feb 7 03:08:13 UTC 2012
/bin/sh: 1: cd: can't cd to /lib/modules/3.2.0-12-virtual/build
Makefile.inc:66: *** /lib/modules/3.2.0-12-virtual/build is missing, please set KERNELPATH. Stop.

$ ls -l /lib/modules/3.2.0-14-virtual/build
lrwxrwxrwx 1 root root 39 Feb 4 00:20 /lib/modules/3.2.0-14-virtual/build -> /usr/src/linux-headers-3.2.0-14-virtual
$ ls -l /lib/modules/3.2.0-12-virtual/build
ls: cannot access /lib/modules/3.2.0-12-virtual/build: No such file or directory

Basically, above I tried to build a dkms module for a version of the kernel other than the current running version.
That failed because I did not have the kernel headers for the current running version.

Ie, it dies saying It needs '3.2.0-12-virtual/build', but I'm trying to build for 3.2.0-14-virtual.

After rebooting into 3.2.0-14-virtual, the same 'build' command above succeeds.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: dkms 2.2.0.3-1
ProcVersionSignature: User Name 3.2.0-12.21-virtual 3.2.2
Uname: Linux 3.2.0-12-virtual x86_64
ApportVersion: 1.91-0ubuntu1
Architecture: amd64
Date: Tue Feb 7 03:03:13 2012
Ec2AMI: ami-00000138
Ec2AMIManifest: FIXME
Ec2AvailabilityZone: nova
Ec2InstanceType: m1.small
Ec2Kernel: unavailable
Ec2Ramdisk: unavailable
PackageArchitecture: all
ProcEnviron:
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: dkms
UpgradeStatus: No upgrade log present (probably fresh install)

[Adam Conrad (adconrad)]

If I recall correctly, I had this same problem with madwifi on my machines, and it's not a bug in dkms at all, it's cargo-culting a broken dkms.conf (which I did as well). Fixing your dkms.conf like so will make it actually build for the version you requested, rather than the running version:

--- dkms_source_tree/dkms.conf 2012-02-07 02:56:37.000000000 +0000
+++ madwifi-0.9.4/dkms.conf 2010-12-04 22:33:11.000000000 +0000
@@ -43,5 +43,5 @@
 BUILT_MODULE_NAME[13]="ath_rate_onoe"
 BUILT_MODULE_LOCATION[13]="ath_rate/onoe"
 DEST_MODULE_LOCATION[13]="/kernel/drivers/net/wireless"
-MAKE[0]="make modules KERNDIR=/lib/modules/$kernelver"
+MAKE[0]="make modules KERNELPATH=/lib/modules/$kernelver/build"
 AUTOINSTALL="yes"