There are some packages that instead of building (or checking) against /usr/src/linux (which the user can select to be a different kernel than the running one) use /lib/modules/`uname -r`/build to build against the currently-running kernel. This is bad in many situations, like: - livecd installs: the running kernel is the one from the livecd and is most likely not the same the user is installing to; - livecd chroot fixes: as above; - generic chroot: running kernel comes from outside, as above; - kernel updates: users most likely would want their system to have all the modules ready _before_ restarting.
All dependent bugs are closed