Re: bug in KBUILD_OUTPUT handling - for relative paths in kselftest

[shuah <shuah@kernel.org>]

On 9/25/19 10:11 PM, Tim.Bird@sony.com wrote:
> I found a bug in kselftest KBUILD_OUTPUT handling.
> 
> The following works:
> $ cd /home/tbird/work/linux
> $ export KBUILD_OUTPUT=/home/tbird/work/kbuild
> $ yes '' | make localmodconfig
> $ make TARGETS=size kselftest
> 
> But this doesn't work:
> $ cd /home/tbird/work/linux
> $ export KBUILD_OUTPUT=../kbuild
> $ yes '' | make localmodconfig
> $ make TARGETS=size kselftest
> 
> I see the following:
> make[1]: Entering directory '/home/tbird/work/kbuild'
>   make --no-builtin-rules INSTALL_HDR_PATH=$BUILD/usr \
>   	ARCH=x86 -C ../../.. headers_install
>     INSTALL ../kbuild/kselftest/usr/include
>   gcc -static -ffreestanding -nostartfiles -s    get_size.c  -o ../kbuild/kselftest/size/get_size
>     /usr/bin/ld: cannot open output file ../kbuild/kselftest/size/get_size: No such file or directory
>   collect2: error: ld returned 1 exit status
>     ../lib.mk:138: recipe for target '../kbuild/kselftest/size/get_size' failed
>   make[3]: *** [../kbuild/kselftest/size/get_size] Error 1
>   Makefile:136: recipe for target 'all' failed
>   make[2]: *** [all] Error 2
>   /home/tbird/work/linux/Makefile:1240: recipe for target 'kselftest' failed
>   make[1]: *** [kselftest] Error 2
>   make[1]: Leaving directory '/home/tbird/work/kbuild'
>   Makefile:179: recipe for target 'sub-make' failed
>   make: *** [sub-make] Error 2
> 
> This is due to the relative path for KBUILD_OUTPUT being handled incorrectly (I believe)
> in tools/testing/selftests/Makefile.
> 

Thanks Tim! I will take a look as part of my work to simplify kselftest
use-cases.

thanks,
-- Shuah