The patch titled
Subject: selftests/arm64: fix build failure during the "emit_tests" step
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
selftests-arm64-fix-build-failure-during-the-emit_tests-step.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-arm64-fix-build-failure-during-the-emit_tests-step.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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From: John Hubbard <jhubbard@xxxxxxxxxx>
Subject: selftests/arm64: fix build failure during the "emit_tests" step
Date: Mon, 10 Jul 2023 17:56:29 -0700
The build failure reported in [1] occurred because commit 9fc96c7c19df
("selftests: error out if kernel header files are not yet built") added a
new "kernel_header_files" dependency to "all", and that triggered another,
pre-existing problem. Specifically, the arm64 selftests override the
emit_tests target, and that override improperly declares itself to depend
upon the "all" target.
This is a problem because the "emit_tests" target in lib.mk was not
intended to be overridden. emit_tests is a very simple, sequential build
target that was originally invoked from the "install" target, which in
turn, depends upon "all".
That approach worked for years. But with 9fc96c7c19df in place,
emit_tests failed, because it does not set up all of the elaborate things
that "install" does. And that caused the new "kernel_header_files" target
(which depends upon $(KBUILD_OUTPUT) being correct) to fail.
Some detail: The "all" target is .PHONY. Therefore, each target that
depends on "all" will cause it to be invoked again, and because
dependencies are managed quite loosely in the selftests Makefiles, many
things will run, even "all" is invoked several times in immediate
succession. So this is not a "real" failure, as far as build steps go:
everything gets built, but "all" reports a problem when invoked a second
time from a bad environment.
To fix this, simply remove the unnecessary "all" dependency from the
overridden emit_tests target. The dependency is still effectively
honored, because again, invocation is via "install", which also depends
upon "all".
An alternative approach would be to harden the emit_tests target so that
it can depend upon "all", but that's a lot more complicated and hard to
get right, and doesn't seem worth it, especially given that emit_tests
should probably not be overridden at all.
[1] https://lore.kernel.org/20230710-kselftest-fix-arm64-v1-1-48e872844f25@xxxxxxxxxx
Link: https://lkml.kernel.org/r/20230711005629.2547838-1-jhubbard@xxxxxxxxxx
Fixes: 9fc96c7c19df ("selftests: error out if kernel header files are not yet built")
Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx>
Reported-by: Mark Brown <broonie@xxxxxxxxxx>
Tested-by: Mark Brown <broonie@xxxxxxxxxx>
Cc: Anders Roxell <anders.roxell@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Muhammad Usama Anjum <usama.anjum@xxxxxxxxxxxxx>
Cc: Nathan Chancellor <nathan@xxxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/arm64/Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/tools/testing/selftests/arm64/Makefile~selftests-arm64-fix-build-failure-during-the-emit_tests-step
+++ a/tools/testing/selftests/arm64/Makefile
@@ -42,7 +42,7 @@ run_tests: all
done
# Avoid any output on non arm64 on emit_tests
-emit_tests: all
+emit_tests:
@for DIR in $(ARM64_SUBTARGETS); do \
BUILD_TARGET=$(OUTPUT)/$$DIR; \
make OUTPUT=$$BUILD_TARGET -C $$DIR $@; \
_
Patches currently in -mm which might be from jhubbard@xxxxxxxxxx are
selftests-arm64-fix-build-failure-during-the-emit_tests-step.patch
