编译模块出现的问题

qiangbing

本人刚学，所以就比着葫芦画瓢，写了一个模块程序，但编译时，出现了很多问题，请各位帮忙。
  我用的编译命令是：gcc -c kersniff.c -O2  -I /usr/src/linux-2.4.20-8/include -o kersniff.o，出现的问题是：In file included from /usr/src/linux-2.4.20-8/include/linux/sched.h:16,
                 from /usr/src/linux-2.4.20-8/include/linux/skbuff.h:19,
                 from kersniff.c:8:
/usr/src/linux-2.4.20-8/include/linux/timex.h:173: field `time' has incomplete type
In file included from /usr/src/linux-2.4.20-8/include/linux/sched.h:23,
                 from /usr/src/linux-2.4.20-8/include/linux/skbuff.h:19,
                 from kersniff.c:8:
/usr/src/linux-2.4.20-8/include/asm/mmu.h:12: field `sem' has incomplete type
In file included from /usr/src/linux-2.4.20-8/include/linux/sched.h:31,
                 from /usr/src/linux-2.4.20-8/include/linux/skbuff.h:19,
                 from kersniff.c:8:
/usr/src/linux-2.4.20-8/include/linux/pid.h:18: field `task_list' has incomplete type
。。。。。。。
但实际上我没有使用头文件<linux/sched.h>;、<linux/pid.h>;等，只用了<linux/skbuff.h>;，有那位大虾知道，麻烦告诉一下，谢谢！