Current kbuild will build the target again if we run "make M=dir" and "make M=dir/" by turns, since if_changed will see the prerequisite is changed. The behavior may confuse the user a little, since actually we are building the same target and no difference. According to current implementation in scripts/Makefile.build, the obj passed to next level is a directory name with last slash stripped. This patch strips the last slash, and slashes in case user doing so, in KBUILD_EXTMOD which is assigned from "M=". Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx> CC: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> --- v2: * remote the temp variable __KBUILD_EXTMOD, since this breaks the user case * use realpath to strips all the slash at the end, then remote the common part if it is an in tree build to make it the same behavior as previous version --- Makefile | 2 ++ 1 file changed, 2 insertions(+) diff --git a/Makefile b/Makefile index b8dfb24b1911..7f12e88cc0fb 100644 --- a/Makefile +++ b/Makefile @@ -191,6 +191,8 @@ ifeq ("$(origin M)", "command line") KBUILD_EXTMOD := $(M) endif +KBUILD_EXTMOD := $(subst $(CURDIR)/,,$(realpath $(KBUILD_EXTMOD))) + # If building an external module we do not care about the all: rule # but instead _all depend on modules PHONY += all -- 2.11.0 -- 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