Seems there is bug in the kernel-devel package that can cause some compile problems also on Centos is seems to work better if u symlink /usr/src/linux to /usr/src/kernels/`uname -r`. https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=180568. There is also a Digium bug about spinlock too. http://bugs.digium.com/view.php?id=6425 The fix is just to fix a small typo in spinlock.h -- Wlliam