CONFIG_DEBUG_FS=y and CONFIG_SYSFS=n results in the following compile error: <-- snip --> ... LD vmlinux fs/built-in.o: In function `debugfs_init': inode.c:(.init.text+0x31be): undefined reference to `kernel_subsys' make: *** [vmlinux] Error 1 <-- snip --> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>