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/[email protected]/
Fixes: ccae4cfa7bfb ("kbuild: refactor scripts/Makefile.modinst")
Reported-by: Johannes Berg <[email protected]>
Signed-off-by: Masahiro Yamada <[email protected]>
---
Changes in v2:
- Use $(filter %/, ) so that the shell invocation is avoided
if M= is already good.
Makefile | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/Makefile b/Makefile
index b79e0e8acbe3..8018b8adbcaf 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.
--
2.27.0
On Wed, Jun 2, 2021 at 11:02 PM Masahiro Yamada <[email protected]> wrote:
>
> 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/[email protected]/
>
> Fixes: ccae4cfa7bfb ("kbuild: refactor scripts/Makefile.modinst")
> Reported-by: Johannes Berg <[email protected]>
> Signed-off-by: Masahiro Yamada <[email protected]>
> ---
Applied to linux-kbuild.
> Changes in v2:
> - Use $(filter %/, ) so that the shell invocation is avoided
> if M= is already good.
>
> Makefile | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/Makefile b/Makefile
> index b79e0e8acbe3..8018b8adbcaf 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.
> --
> 2.27.0
>
--
Best Regards
Masahiro Yamada