When I compile my module I got these messages: *** Warning: "kobject_del" [drivers/isdn/capi/rcapidrv.ko] undefined! *** Warning: "kobject_add" [drivers/isdn/capi/rcapidrv.ko] undefined! And insmod'ing my module fails, because of the undefined symbols. My module uses some of the kobject_ functions defined in linux/kobject.h. If I comment kobject_add/del() out -- and leave all other kobject_() functions(e.g. kobject_set_name()), then the compilation will not more complain and inserting the module succeeds. cat /proc/kallsyms shows me: c019cb18 T kobject_init c019cb58 t unlink c019cbb4 t kobject_add c019ccc4 T kobject_register c019cd0c T kobject_set_name c019cdbc t kobject_rename c019cde8 t kobject_del c019ce40 T kobject_unregister c019ce58 T kobject_get c019ce98 t kobject_cleanup c019cf08 T kobject_put Apparently, kobject_add/del() are there. The only difference, that I have noticed, is that kobject_add/del() and some others, have a lower `t' instead of a capital `T'. What is the difference between them? What to do in order to compile/insert my module successfully? /FAU -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/