Linux内核模块编译报错：compiler-gcc.h:164:38: error: impossible constraint in ‘asm’

现象：编译内核模块时遇到错误提示

/usr/src/linux-headers-4.19.0-6-common/include/linux/compiler-gcc.h:164:38: error: impossible constraint in ‘asm’

 #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)

原因：gcc高版本编译器在-O0选项下不支持部分优化代码

解决：将-O0改为-O1及以上即可。

参考：optimization - How to prevent gcc optimizing in kernel modules? - Stack Overflow