Re: [PATCH v3 5/7] tools: build kernel selftests in tools_build

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] tools: missing shared Makefile dependencies in selftest-shared rule
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commit 730c01fcefa10c1ac883951ece76358d414b16b5
Author: Sasha Levin <sashal@kernel.org>

tools: build kernel selftests in tools_build

This commit adds a Kconfig sub-menu and Makefile rules to build selected
kernel selftests in parallel as part of tools_build, tracking shared headers
and makefiles to trigger clean rebuilds when dependencies change.

> diff --git a/tools/Makefile.kbuild b/tools/Makefile.kbuild
> index 4b3ea73bc8ab9..590440121c8c9 100644
> --- a/tools/Makefile.kbuild
> +++ b/tools/Makefile.kbuild

[ ... ]

> @@ -89,6 +90,119 @@ PHONY += perf

[ ... ]

> +$(selftest-shared): FORCE
> +	$(Q)mkdir -p $(@D); \
> +	newest=$$(find $(CURDIR)/usr/include $(toolsdir)/include $(toolsdir)/arch $(toolsdir)/testing/selftests \
> +		-type f \( -name '*.h' -o -name '*.mk' -o -name Makefile \) -printf '%T@\n' | \
> +		sort -n | tail -n 1); \
> +	touch -d "@$${newest:-0}" $@

[Severity: Medium]
As reported by Sashiko on RFC v2 [1], in tools/Makefile.kbuild, the
$(selftest-shared) rule searches $(CURDIR)/usr/include, $(toolsdir)/include,
$(toolsdir)/arch, and $(toolsdir)/testing/selftests for files matching *.h,
*.mk, or Makefile.

Several selftests enabled by this patch include shared makefile fragments
outside those paths and filename patterns:

- tools/testing/selftests/kexec/Makefile and
  tools/testing/selftests/vDSO/Makefile include
  ../../../scripts/Makefile.arch (i.e. $(toolsdir)/scripts/Makefile.arch).

- tools/testing/selftests/rseq/Makefile,
  tools/testing/selftests/thermal/intel/power_floor/Makefile, and
  tools/testing/selftests/thermal/intel/workload_hint/Makefile include
  $(top_srcdir)/scripts/subarch.include (i.e.
  $(abs_srctree)/scripts/subarch.include).

Since neither file is covered by the find command in $(selftest-shared) or
listed in $(selftest-extra-$*), and lib.mk does not list Makefiles as
prerequisites of built test binaries, won't modifying
tools/scripts/Makefile.arch or scripts/subarch.include fail to update
$(selftest-shared) and leave stale selftest build artifacts during incremental
builds?

[1] https://lore.kernel.org/r/sashiko-outbox-175556@kernel.org

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Sashiko AI review · https://sashiko.dev/#/patchset/20261102021253.2545235-1-sashal@kernel.org?part=5