with modular kernel I get:

(...)
  Building modules, stage 2.
  MODPOST
*** Warning: "__down_read_trylock" [fs/xfs/xfs.ko] undefined!
*** Warning: "compat_init_rwsem" [fs/xfs/xfs.ko] undefined!
*** Warning: "__down_write" [fs/xfs/xfs.ko] undefined!
*** Warning: "__downgrade_write" [fs/xfs/xfs.ko] undefined!
*** Warning: "__up_read" [fs/xfs/xfs.ko] undefined!
*** Warning: "__up_write" [fs/xfs/xfs.ko] undefined!
*** Warning: "__down_write_trylock" [fs/xfs/xfs.ko] undefined!
*** Warning: "__down_read" [fs/xfs/xfs.ko] undefined!
*** Warning: "compat_init_rwsem" [fs/jffs2/jffs2.ko] undefined!
*** Warning: "__down_write" [fs/jffs2/jffs2.ko] undefined!
*** Warning: "__up_read" [fs/jffs2/jffs2.ko] undefined!
*** Warning: "__up_write" [fs/jffs2/jffs2.ko] undefined!
*** Warning: "__down_read" [fs/jffs2/jffs2.ko] undefined!
(...)

-- 
The only thing necessary for the triumph of evil
  is for good men to do nothing.
                                           - Edmund Burke