This problem starts from the bad design of the kselftest framework. I did some research before. I think I can fix the root cause but currently I do not have enough time to do it.
KBUILD_ABS_SRCTREE is a user-interface to request Kbuild to use the absolute path. If it is forced in the top Makefile, users have no way to negate it. It is true that using the absolute path is a quick work-around because you do not need to care about the current working directory.
If you insist on it, just go ahead. It is just two line changes. Once the issue is fixed in a better way, your patch can be reverted easily.
Why don't we work on fixing it the wright way? I would rather go that route than using short rem fixes.
Usama, would you be interested in working on a proper fix as recommended by Masahiro?
I've made another attempt: https://lore.kernel.org/lkml/20220627070214.432390-1-usama.anjum@collabora.c...
thanks, -- Shuah