[lug] What tweaks are done to kernels by distributors

[Jonathan Corbet]

> In general, what tweaks do Linux distributors do to the kernel before
> releasing it in their versions of Linux?

It varies a lot from one distribution to the next.  Red Hat patches
extensively; Debian relatively little.

I looked at a couple of examples last spring:

	http://lwn.net/2000/0504/kernel.php3  Linux-mandrake
	http://lwn.net/2000/0511/kernel.php3  Caldera
	
I've not looked at more recent kernels.  I know RH had some obnoxious
patches, including backporting part of the 2.4 API to 2.2, making some
device drivers break.

The real way to get an answer for specific distribution, of course, is to
install the source package (and, for RH, the "source RPM" is not the same
as the "kernel source" package you can put in at install time - the latter
is already patched).  Look in the spec file and you'll see all the patches
split out.

> I ask this because I want to upgrade my RH 7.0 kernel to 2.2.18, which
> RH has not released under their own version. (I do not want to go to
> 2.4 right now).
> 
> I was thinking of using the version available from kernel.org, but am
> wondering what kind of problems that this might cause since it is not
> RH "tweaked".

Unless you're doing something strange, you will almost certainly get away
with it.  Watch out if you're using RAID, since RH, like most distributors,
has backported the 2.4 (i.e. "working") RAID implementation to 2.2.
Otherwise you should be OK.

Jonathan Corbet
Executive editor, LWN.net
corbet at lwn.net