Build of kselftests fail if kernel's top most Makefile is used for running or building kselftests with separate output directory. The absolute path is needed to reference other files during this kind of build. Set KBUILD_ABS_SRCTREE to use absolute path during the build. It fixes the following different types of errors: make kselftest-all O=/linux_mainline/build Makefile:1080: ../scripts/Makefile.extrawarn: No such file or directory make kselftest-all O=build Makefile:1080: ../scripts/Makefile.extrawarn: No such file or directory Signed-off-by: Muhammad Usama Anjum <usama.anjum@xxxxxxxxxxxxx> --- I've tested this patch on top of next-20220217. The latest next-20220222 have missing patches. --- Makefile | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/Makefile b/Makefile index 86f633c2809ea..62b3eb8a102ab 100644 --- a/Makefile +++ b/Makefile @@ -1411,10 +1411,10 @@ tools/%: FORCE PHONY += kselftest kselftest: - $(Q)$(MAKE) -C $(srctree)/tools/testing/selftests run_tests + $(Q)$(MAKE) -C $(srctree)/tools/testing/selftests KBUILD_ABS_SRCTREE=1 run_tests kselftest-%: FORCE - $(Q)$(MAKE) -C $(srctree)/tools/testing/selftests $* + $(Q)$(MAKE) -C $(srctree)/tools/testing/selftests KBUILD_ABS_SRCTREE=1 $* PHONY += kselftest-merge kselftest-merge: -- 2.30.2