modify Makefile
obj-m := hello_md.o
#KDIR := /lib/modules/$(shell uname -r)/build
KDIR := /work/kernel
PWD := $(shell pwd)
all:
$(MAKE) -C $(KDIR) SUBDIRS=$(PWD) modules
clean:
rm -f *.0
rm -f -f *.mod.*
root@jcjung:/work/simple_module# file hello_md.ko
hello_md.ko: ELF 32-bit LSB relocatable, ARM, version 1 (SYSV), not stripped
root@jcjung:/work/simple_module# cp hello_md.ko /var/lib/tftpboot/
bash-3.2# /sbin/busybox uname -a
Linux localhost 2.6.32 #171 Tue Jul 26 09:19:21 KST 2011 armv7l unknown
bash-3.2# tftp -g 192.168.10.10 -r hello_md.ko
bash-3.2# insmod hello_md.ko
hello_md: no symbol version for module_layout
insmod: cannot insert 'hello_md.ko': invalid module format (-1): Exec format err
kernel version is different. That's the reason you met error.