sizeof problem in kernel modules

[Der Herr Hofrat]

Hi !

 can someone explain to me whats happening here ?

--simple.c--
#include <linux/module.h>
#include <linux/kernel.h>

struct { short x; long y; short z; }bad_struct;
struct { long y; short x; short z; }good_struct;

int init_module(void){
	printk("good_struct %d, bad_struct %d\n",sizeof(good_struct),sizeof(bad_struct));
	return 0;
}

void cleanup_module(void){
	}

--Makefile--

all: simple.o

CC= gcc 
CFLAGS= -pipe -fno-strength-reduce -DCPU=686 -march=i686 \
	-Wall -Wstrict-prototypes -g -D__KERNEL__ -DMODULE \
	-D_LOOSE_KERNEL_NAMES -O2   -c 
INCLUDE= -I/usr/include/linux 

clean:
	rm -f simple.o

---------------------------------------------------------------

I would expect both structs to be 8byte in size , or atleast the same size !
but good_struct turns out to be 8bytes and bad_struct 12 .

what am I doing wrong here ?

thx !
hofrat