With my Slackware machines I usualy compile my own kernel to get rid of features I don't need and build in modules that I do need.
In my boot loader I usually have two entries. One for a working kernel and one for a test kernel.

When building my kernels I have always run:
1) make dep
2) make clean
3) make bzImage

and then copy the newly built kernel to the location of the test kernel as specified in the boot loader.
ie. /boot/vmlinuz.tst

Well I don't directly copy it directly to that location.
I actually copy it to /boot/vmlinuz.tst.new
and then use the mv command to rename /boot/vmlinuz.tst to /boot/vmlinuz.tst.sav
and use mv to rename /boot/vmlinuz.tst.new to /boot/vmlinuz.tst

Anyway. The other day I decided to build in some of the modules used by my Slackware64 14.1 desktop machine into the kernel.
I did my usual steps for compiling a new kernel. WITH one difference.
I've noticed that within the past year or so. That when running "make dep" I would get a message that "make dep" is no longer required.
So this time I only ran "make clean" and "make bzImage". And then did my usual steps for booting with the test kernel I just built.

Using this new kernel I noticed that many programs were not running. Because they were failing to find required modules running.
Modules that I just built into this new kernel. So I tried loading them with modprobe.
But they failed to load with "ERROR: could not insert Exec format error" and something about owned by the kernel.

So I then rebooted with my working kernel. BUT it had the exact same issues.
Since it was late at night I was afraid I accidently overwrote my working kernel and restored it from backup.
But even the restored kernel had the same issues.

So I rebuilt my working kernel by using the .config that was saved from when it was first built.
But even that kernel had the same issues.

I finally resorted to rebuilding my working kernel AND rebuilding all modules with "make modules module_install".
That solved the issue.
But now I am right back to where I was before I attempted to build needed module into the kernel.

So my questions are:
1) What happened and why did the modules have to be rebuilt ?
2) Is "make dep" truly needed ? And that message about it not being needed; is bogus ?


Thanks;
--ET

make dep have been obsoleted a long time ago (since Linux 2.6 IIRC).

Of course you need to build and install the modules every time you compile a kernel.

to know the available targets for "make" type "make help" in /usr/src/linux-<version>.

Just follow Pat's instructions: see in the installation media the file /source/k/README.TXT, but in addition do not forget make modules && make modules_install

Or if you want more details, see these instructions provided by Eric Hameleers.

My steps for building a Linux kernel:

1) download source from kernel.org and uncompress the downloaded file
2) cd into the kernel directory
3) run make mrproper
4) prepare a .config file in the kernel directory (I typically cp the config file from the running kernel into the kernel directory and then run make olddefconfig)
5) then i run make -j7 (to take advantage of my multicore processor)
6) then i su into root
7) next i run make modules_install
8) then i copy the bzImage, System.map, and .config files to the their respective files in the /boot directory
9) modify /etc/lilo.conf properly
10) finally run /sbin/lilo -v and reboot to the new kernel

So basically for me it's:
make mrproper
make olddefconfig
make -j7
make modules_install

Lumpy

Thanks for the replies.

But I'm still curious as to why I had to rebuild the modules this time.
In the past I've never had to rebuild modules when rebuilding a kernel. And never encountered any issues during those times.

Compatibility of an old module with a more recent kernel vary. But it's useless to take a risk, so you should _always_ rebuild and install the modules when you compile and install a new kernel. Recommended reading: