转载：http://wenx05124561.blog.163.com/blog/static/124000805201223112811490/
一．BUG_ON
Linux中BUG_ON，WARN_ON用于调试，比如
#define BUG_ON(condition) do { /
if (unlikely((condition)!=0)) /
BUG(); /
} while(0)
如果觉得该condition下是一个BUG，可以添加此调试信息，查看对应堆栈内容
具体的BUG_ON最终调用__bug
__bug
{
*（int*)0=0;
}
从而地址非法访问，
例如在你的驱动中调用BUG_ON(1),dmesg会出现下面类似信息
[ 19.360000] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[ 19.360000] pgd = c0004000
[ 19.360000] [00000000] *pgd=00000000
函数的调用流程为
代码流程，
fault.c
__do_kernel_fault--------[ 19.360000] Unable to handle kernel NULL pointer dereference at virtual address 00000000
traps.c
die--->__die--->__show_regs / dump_mem
二．WARN_ON
而WARN_ON则是调用dump_stack，打印堆栈信息，不会OOPS
23 #define WARN_ON(condition) do { /
24 if (unlikely((condition)!=0)) { /
25 printk("Badness in %s at %s:%d/n", __FUNCTION__, __FILE__, __LINE__); /
26 dump_stack(); /
27 } /
28 } while (0)
三．BUILD_BUG_ON
#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
BUILD_BUG_ON宏中的condition如果为真就会报错。假设条件为真，则BUILD_BUG_ON变化为：(void) sizeof (char[-1])，这种语法是在难理解，因为char[-1]本来就是非法的。结果导致编译错误。
例子：
#define condition 0
static int __init main_init(void)
{
printk("in %s function ", __func__);
BUILD_BUG_ON(condition);/*if the macro "confition" is not zero, the program can not be compiled to success. so the BUILD_BUG_ON used for the build of program*/
WARN_ON(!condition);/*if the macro "confition" is not zero, there will dump the satck information for this program. so the WARN_ON used for debugof program*/
BUG_ON(condition); /*if the macro "confition" is not zero, The kernel will occur an Oops errro "Unable to handle kernel NULL pointer dereference at virtual address 00000000". so the BUG_ON used for ending the bug program*/
return 0;
}