debian:/home/atul# gcc -c hello.c In file included from /usr/include/asm-i486/local.h:4, from /usr/include/asm/local.h:8, from /usr/include/linux/module.h:20, from hello.c:2: /usr/include/linux/percpu.h: In function ‘__alloc_percpu’: /usr/include/linux/percpu.h:44: error: ‘GFP_KERNEL’ undeclared (first use in thi s function) /usr/include/linux/percpu.h:44: error: (Each undeclared identifier is reported o nly once /usr/include/linux/percpu.h:44: error: for each function it appears in.) In file included from /usr/include/asm/module.h:8, from /usr/include/linux/module.h:22, from hello.c:2: /usr/include/asm-i486/module.h:60:2: error: #error unknown processor family In file included from hello.c:2: /usr/include/linux/module.h: At top level: /usr/include/linux/module.h:49: error: field ‘attr’ has incomplete type /usr/include/linux/module.h:60: error: field ‘kobj’ has incomplete type