This is a note to let you know that I've just added the patch titled
kbuild: remove trailing slashes from $(KBUILD_EXTMOD)
to the 5.13-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kbuild-remove-trailing-slashes-from-kbuild_extmod.patch
and it can be found in the queue-5.13 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit cbb4600303d10e74b981dfd478aee3f30068bc38
Author: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Date: Wed Jun 2 23:02:13 2021 +0900
kbuild: remove trailing slashes from $(KBUILD_EXTMOD)
[ Upstream commit 74ee585b7eecd98be3650e677625a0ee588d08e0 ]
M= (or KBUILD_EXTMOD) generally expects a directory path without any
trailing slashes, like M=a/b/c.
If you add a trailing slash, like M=a/b/c/, you will get ugly build
logs (two slashes in a series), but it still works fine as long as it
is consistent between 'make modules' and 'make modules_install'.
The following commands correctly build and install the modules.
$ make M=a/b/c/ modules
$ sudo make M=a/b/c/ modules_install
Since commit ccae4cfa7bfb ("kbuild: refactor scripts/Makefile.modinst"),
a problem happens if you add a trailing slash only for modules_install.
$ make M=a/b/c modules
$ sudo make M=a/b/c/ modules_install
No module is installed in this case, Johannes Berg reported. [1]
Trim any trailing slashes from $(KBUILD_EXTMOD).
I used the 'dirname' command to remove all the trailing slashes in
case someone adds more slashes like M=a/b/c/////. The Make's built-in
function, $(dir ...) cannot take care of such a case.
[1]: https://lore.kernel.org/lkml/10cc8522b27a051e6a9c3e158a4c4b6414fd04a0.camel@xxxxxxxxxxxxxxxx/
Fixes: ccae4cfa7bfb ("kbuild: refactor scripts/Makefile.modinst")
Reported-by: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/Makefile b/Makefile
index 83f4212e004f..4258a60f6119 100644
--- a/Makefile
+++ b/Makefile
@@ -129,6 +129,11 @@ endif
$(if $(word 2, $(KBUILD_EXTMOD)), \
$(error building multiple external modules is not supported))
+# Remove trailing slashes
+ifneq ($(filter %/, $(KBUILD_EXTMOD)),)
+KBUILD_EXTMOD := $(shell dirname $(KBUILD_EXTMOD).)
+endif
+
export KBUILD_EXTMOD
# Kbuild will save output files in the current working directory.
