From 9a68fd7fd8b05050b27ae67a829a2035b2b7a993 Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <masahiroy@kernel.org>
Date: Thu, 14 Jul 2022 14:02:42 +0900
Subject: kbuild: error out if $(KBUILD_EXTMOD) contains % or :

If the directory path given to KBUILD_EXTMOD (or M=) contains % or :,
the module fails to build.

% is used in pattern rules, and : as the separator of dependencies.

Bail out with a clearer error message.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
---
 Makefile | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'Makefile')

diff --git a/Makefile b/Makefile
index f8e325709bf3..dee707c98bbe 100644
--- a/Makefile
+++ b/Makefile
@@ -129,6 +129,9 @@ endif
 $(if $(word 2, $(KBUILD_EXTMOD)), \
 	$(error building multiple external modules is not supported))
 
+$(foreach x, % :, $(if $(findstring $x, $(KBUILD_EXTMOD)), \
+	$(error module directory path cannot contain '$x')))
+
 # Remove trailing slashes
 ifneq ($(filter %/, $(KBUILD_EXTMOD)),)
 KBUILD_EXTMOD := $(shell dirname $(KBUILD_EXTMOD).)
-- 
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