Re: [PATCH] selftests: Makefile: add missing 'net/lib' to targets

[Jakub Kicinski <kuba@kernel.org>]

On Sun, 15 Sep 2024 09:36:10 +0200 Willem de Bruijn wrote:
> > You’re right, the patch is incorrect, I could have explained better.
> > I’m seeing an issue with an out-of-tree cross compilation build of
> > kselftest and can’t figure out what’s wrong.
> >
> > make --keep-going --jobs=32 O=/tmp/build
> > INSTALL_PATH=/tmp/build/kselftest_install \
> >      ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- \
> >      CROSS_COMPILE_COMPAT=arm-linux-gnueabihf- kselftest-install
> >
> > [...]
> > make[4]: Entering directory
> > '/home/anders/src/kernel/linux/tools/testing/selftests/net/lib'
> >   CC       csum
> > /usr/lib/gcc-cross/aarch64-linux-gnu/13/../../../../aarch64-linux-gnu/bin/ld:
> > cannot open output file /tmp/build/kselftest/net/lib/csum: No such
> > file or directory
> > collect2: error: ld returned 1 exit status
> > [...]
> >
> > Any thoughts on what might be causing this?  
> 
> I wonder if this is due to the O= argument.
> 
> Last week I noticed that some TARGETs explicitly have support for
> this, like x86. Added in 2016 in commit a8ba798bc8ec6 ("selftests:
> enable O and KBUILD_OUTPUT"). But by now this support is hardly
> universal. amd-pstate does not have this infra, for instance.
> 
> Though if the only breakage is in net/lib, then that does not explain it fully.

Some funny business with this install target, I haven't investigated
fully but the dependency on all doesn't seem to do its job, and the
install target has a copy/paste of all with this line missing:

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 3b7df5477317..3aee8e7b9993 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -261,6 +261,7 @@ ifdef INSTALL_PATH
 	@ret=1;	\
 	for TARGET in $(TARGETS) $(INSTALL_DEP_TARGETS); do \
 		BUILD_TARGET=$$BUILD/$$TARGET;	\
+		mkdir -p $$BUILD_TARGET;	\
 		$(MAKE) OUTPUT=$$BUILD_TARGET -C $$TARGET install \
 				INSTALL_PATH=$(INSTALL_PATH)/$$TARGET \
 				SRC_PATH=$(shell readlink -e $$(pwd)) \


Andres, please feel free to test / write commit message and submit this
one liner, but even with that the build for some targets fails for me.
"make [..] install" seems wobbly.