Hi, I am trying a new gcc with new warnings enabled: make O=../a/gcc7/ CC='gcc-7' V=1 kernel/exit.o EXTRA_CFLAGS='-Wimplicit-fallthrough=3' But the build fails when building under tools/: ... make -f /home/latest/linux/tools/build/Makefile.build dir=. obj=fixdep gcc -Wp,-MD,/home/latest/a/gcc7/tools/objtool/.exec-cmd.o.d,-MT,/home/latest/a/gcc7/tools/objtool/exec-cmd.o -Wbad-function-cast -Wdeclaration-after-statement -Wformat-security -Wformat-y2k -Winit-self -Wmissing-declarations -Wmissing-prototypes -Wnested-externs -Wno-system-headers -Wold-style-definition -Wpacked -Wredundant-decls -Wshadow -Wstrict-aliasing=3 -Wstrict-prototypes -Wswitch-default -Wswitch-enum -Wundef -Wwrite-strings -Wformat -Wimplicit-fallthrough=3 -ggdb3 -Wall -Wextra -std=gnu99 -O6 -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -fPIC -Werror -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE -I/home/latest/linux/tools/include/ -I/home/latest/linux/include/uapi -I/home/latest/linux/include -D"BUILD_STR(s)=#s" -c -o /home/latest/a/gcc7/tools/objtool/exec-cmd.o exec-cmd.c gcc: error: unrecognized command line option ‘-Wimplicit-fallthrough=3’; did you mean ‘-Wno-fallthrough’? Apparently, CC is not respected for tools/ dir. Well, it is used (tools/build/Makefile.build): # Compile command quiet_cmd_cc_o_c = CC $@ cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< But I don't know why CFLAGS propagate from Makefile to tools/, but CC doesn't (both are exported)? Any ideas? thanks, -- js suse labs -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html