kernel HEAD && userland 7.0-REL?

[Robert Watson]

On Fri, 4 Jul 2008, Matthias Apitz wrote:

> I'm running a RELENG_7 kernel and a userland as 7.0-REL on one of my 
> laptops; I've been asked to check if a given driver problem in RELENG_7 is 
> as well with HEAD... can I update the kernel to HEAD and let the userland 
> (and all my compiled ports) as 7.0-REL; I know that this is not the 
> intention, but it would cost me a lot of work if I should compile as well 
> ~200 ports....

As a general rule, running old userspace on a new kernel works pretty well, 
but you should expect certain types of things to not work -- for example, 
monitoring tools that expect the kernel layout of data structures to be 
unchanged.  Within a particular -STABLE branch this is a bit less volatile, 
but as you go from, say, 6-STABLE to a 7-STABLE kernel, the chances that some 
of the more obscure options to netstat, etc, will not work are pretty high. 
Likewise, be careful to disable any third-party kernel modules that may 
require recompiling but aren't caught by the base system build, or you'll get 
a nasty surprise when they panic. :-)

Robert N M Watson
Computer Laboratory
University of Cambridge