kbuild: make module name conflict fatal error

I think all the warnings have been fixed by now. Make it a fatal error.

Check it before modpost because we need to stop building *.ko files.
Also, pass modules.order via a script parameter.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Makefile

@@ -1335,9 +1335,12 @@ all: modules
 # using awk while concatenating to the final file.
 
 PHONY += modules
-modules: $(if $(KBUILD_BUILTIN),vmlinux) modules.order
+modules: $(if $(KBUILD_BUILTIN),vmlinux) modules_check
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
-	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/modules-check.sh
+
+PHONY += modules_check
+modules_check: modules.order
+	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/modules-check.sh $<
 
 modules.order: descend
 	$(Q)$(AWK) '!x[$$0]++' $(addsuffix /$@, $(build-dirs)) > $@

scripts/modules-check.sh

@@ -3,14 +3,24 @@
 
 set -e
 
+if [ $# != 1 ]; then
+	echo "Usage: $0 <modules.order>" >& 2
+	exit 1
+fi
+
+exit_code=0
+
 # Check uniqueness of module names
 check_same_name_modules()
 {
-	for m in $(sed 's:.*/::' modules.order | sort | uniq -d)
+	for m in $(sed 's:.*/::' $1 | sort | uniq -d)
 	do
-		echo "warning: same module names found:" >&2
+		echo "error: the following would cause module name conflict:" >&2
 		sed -n "/\/$m/s:^:  :p" modules.order >&2
+		exit_code=1
 	done
 }
 
-check_same_name_modules
+check_same_name_modules "$1"
+
+exit $exit_code