panic "Sleeping thread owns a non-sleepable lock" via cv_timedwait_signal, was "rsync over NFS"

[Norbert Aschendorff]

I exported the NFSv4 shares via nullfs, booted the 10.0-CURRENT kernel
and the machine does not crash. Running 9.1-PRERELEASE, it still crashes
(as it should ;).

I just applied the numeric-uidgid patch to CURRENT (worked so far) and
compile the kernel with the patch and try it another time, just to
eliminate the possibility of a bug in this patch (the machine never
crashed before using this patch, but I'm not sure if I tested this
consciously before having applied the patch)

--Norbert