What I really want is to re-enable GCC's uninitialized variable warning. $ rm drivers/vdpa/ifcvf/ifcvf_main.o $ make W=2 drivers/vdpa/ifcvf/ifcvf_main.o It prints a ton of output but this is the relevant bit. drivers/vdpa/ifcvf/ifcvf_main.c: In function ?ifcvf_vdpa_set_status?: drivers/vdpa/ifcvf/ifcvf_main.c:291:6: warning: ?config_vector? may be used uninitialized in this function [-Wmaybe-uninitialized] int config_vector, ret; ^~~~~~~~~~~~~ regards, dan carpenter