title: Makefile make: Nothing to be done for `default'
body: <p>I write a hello.c:</p>
  
  <pre><code>#include &lt;linux/init.h&gt;
  #include &lt;linux/moudle.h&gt;
  
  static int hello_init(void)
  {
      printk(KERN_ALERT "Hello, World\n");
      return 0;
  }
  
  static void hello_exit(void)
  {
      printk(KERN_ALERT "GoodBye, cruel Workd!\n");
  }
  
  module_init(hello_init);
  module_exit(hello_exit);
  module_LICENSE("GPL");
  module_AUTHOR("ChangZhi");
  </code></pre>
  
  <p>And this is Makefile:</p>
  
  <pre><code>obj-m := hello.o
  KERNEL_DIR := /lib/modules/$(shell uname -r)/build
  PWD := $(shell pwd)
  default:
  make -C $(KERNEL_DIR) SUBDIRS=$(PWD) modules
  #clean:
  #rm *.o *.ko *.mod.c
  
  .PHONY:clean
  </code></pre>
  
  <p>when I run <code>make</code>, the shell displays <code>make: Nothing to be done for</code>default'.`. Could someone help me? Thanks a lot !</p>