Hello,

not sure if it was still pointed here, so:
in RHEL6 (and so in SL6, and the later Fedora) Redhat changed the output 
of 'uname'. Now the arch is added to the kernel version.
It means that on my SL6 I get:
uname -r
2.6.32-71.18.2.el6.x86_64
whereas on a SL5 I get:
2.6.18-238.12cc.el5 (do not mind the strange release version, we use a 
patched version of our own).

It is a small change, but it can makes people loosing time to find out 
why some existing stuff brokes on SL6 (such as using "uname -r" to build 
kernel dependancies in SPEC files or using it to verify the installed 
kernel).

It was just to share - I loose a little of my time when building some 
kernel modules.

Regards,
--
Y.