../net/ipv4/nexthop.c: note: in included file (through ../include/linux/sysctl.h, ../include/net/net_namespace.h, ../include/linux/netdevice.h, ../include/linux/rtnetlink.h): ../include/linux/rbtree.h:74:9: error: incompatible types in comparison expression (different address spaces): ../include/linux/rbtree.h:74:9: struct rb_node [noderef] __rcu * ../include/linux/rbtree.h:74:9: struct rb_node * ../arch/x86/boot/version.c:18:12: warning: symbol 'kernel_version' was not declared. Should it be static? ../net/ipv4/nexthop.c: note: in included file (through ../include/linux/sysctl.h, ../include/net/net_namespace.h, ../include/linux/netdevice.h, ../include/linux/rtnetlink.h): ../include/linux/rbtree.h:74:9: error: incompatible types in comparison expression (different address spaces): ../include/linux/rbtree.h:74:9: struct rb_node [noderef] __rcu * ../include/linux/rbtree.h:74:9: struct rb_node * ../arch/x86/boot/version.c:18:12: warning: symbol 'kernel_version' was not declared. Should it be static?