---------- Forwarded message ---------- From: harryxiyou <harryxiyou@gmail.com> Date: Thu, Apr 5, 2012 at 4:20 PM Subject: [RFC]Module problem To: linux-kernel@vger.kernel.org Hi list, When i write an easy module for testing, it happens to me a problem, which is like this "Building modules, stage 2.  MODPOST 0 modules". I can not find the *.ko file. My Module file is like this: hello.c #include <linux/module.h> #include <linux/kernel.h> #include <linux/init.h> static int __init hello_init(void) { printk("<1> Hello World\n"); return 0;  } static void __exit hello_exit(void) { printk("<1> Goodbey\n"); return ;  } MODULE_LICENSE("GPL"); module_init(hello_init); module_exit(hello_exit); Makefile is like this: obj-m += hello.o all:                make -C /usr/src/linux-headers-3.0.0-12-generic M=/home/sel/homeworl modules clean:               make -C /usr/src/linux-headers-3.0.0-12-generic M=/home/sel/homeworl clean   When i compile my modules as up Makefile, i cannot get my hello.ko file. However, when i change the Makefile like following it is ok for me. obj-m :=hello.o ifneq ($( KERNELRELEASE),) else KERNELDIR ?= /lib/modules/$(shell uname -r)/build PWD :=$(shell pwd) default:             $(MAKE) -C $(KERNELDIR) M=$(PWD) modules endif     I cannot understand this well Makefile clearly. Cloud anyone give me a help ;-) My kernel version is 2.6. Ubuntu 10.04. x86 32bits. -- Thanks Harry Wei -- Thanks Harry Wei