If I am running kdm and I choose the reboot option in the KDE exit
menu, my KDE session is shut down properly, but the machine does not
reboot.

In the logs, I see:

audit(1083816206.762:0): avc:  denied  { write } for  pid=2764
exe=/usr/bin/kdeinit name=xdmctl-:0 dev=hda2 ino=1144796
scontext=aleksey:staff_r:staff_t
tcontext=system_u:object_r:xdm_var_run_t tclass=fifo_file

IMHO this should be fixed by either relocating the xdmctl into
/tmp/.X11-unix, or explicitly making sure it has the same type as
/tmp/.X11-unix/X0 (currently - xdm_xserver_tmp_t) which users are
allowed to write to.

kdebase-3.2.2-4 policy-sources-1.11.2-21