Yeah.........I was having the same problem and was starting to get gray hairs!!!!!
I used the usual method with slackpkg to upgrade from sw 13.1 to 13.37, all seemed well, until I tried to start KDE and it would get through the first four icons on the splash screen, but right before the big K would materialize, it would crash, every time, with a segmentation 11 error and other messages.
Using xwmconfig I took xfce, fvwm, and fluxbox for a test drive, even running K apps such as Kword, Kwrite, Kspread, Kcal, Konsole in those desktops, all worked fine, but KDE itself simply would not cooperate.
I saw it mentioned in many places, and it IS in the changelog that if KDE crashes on startup, to disable compositing, - which simply means that the video card cannot handle 3D ---by creating a file named disable-composite.conf thusly:
/etc/X11/xorg.conf.d/disable-composite.conf
Yeah, it was news to me that the traditional xorg.conf file is not used (although it can be) and that udev now handles this.
So I made the disable-composite.conf file with jstar, putting in the three lines of code it says to put, still got nowhere. On another thread I saw someone was having a similar problem, but running in a virtual box, and they said to put 7 spaces, that's SEVEN SPACES before the word option. I did that, and it solved the problem!!!
At the risk of being overly verbose:
this: (does not work)
Section "Extensions"
Option "Composite" "Disable"
EndSection
is not the same as this: (does work)
Section "Extensions"
Option "Composite" "Disable"
EndSection
because in this line:
Option "Composite" "Disable"
^^^^^^<-----you MUST put seven spaces before the word option
EDIT: It's not rendering here as I've typed it, but just be sure to put 7 spaces before the word Option and you'll be fine
FYI, this machine is an old Compaq Deskpro, with a 500 mhz CPU and 128 megs RAM. At first I simply thought KDE had just gotten too bloated, but it does run on this machine, although of course it is slow. I call this my 'crash test dummy' machine, and I always use it for upgrade experiments before I try it on one of my good/important machines. I've had a few upgrade disasters, namely sw 12.2 to 13.0 and then from 13.0 to 13.1. Ultimately I did a clean 13.1 install from CD and found it much better than 13.0, and now that this upgrade is viable I look forward to using 13.37. SW 12.2 and KDE 3.5.10 remain on my 'main' machine as I am still very partial to that, and although it took some getting used to KDE 4 with all it's over widgetness and windoz-y manners, I do like it.
Hope the above helps someone that may have also gotten stuck with the whole 'compositing' issue