[PATCH v3 0/2] selftests/livepatch: fix building and running outside the host kernel

[Sasha Levin <sashal@kernel.org>]

The livepatch test modules are built against the running host kernel
even when the selftests are built for a kernel in an output directory,
and the scripts skip every test on a machine without a kernel build
tree, even when the modules were built and installed with the
selftests.

Patch 1 picks KDIR from O or KBUILD_OUTPUT, stops passing O and
KBUILD_OUTPUT on to the module build, and skips the modules for kernels
without CONFIG_LIVEPATCH. Patch 2 makes the scripts check for the test
modules instead of a kernel build tree.

Tested on v7.4-rc1 with an x86_64 kernel with CONFIG_LIVEPATCH built in
an output directory. The modules build against it with relative and
absolute O and KDIR, through tools/testing/selftests and through the
kernel's kselftest targets, and clean removes them in all of those
cases, also after Module.symvers is gone. The installed tree was run in
a VM that has no build directory for that kernel: all 8 livepatch tests
pass, and they skip cleanly when test_modules/ is missing.

Changes since v2:
- Patch 1: clean test_modules through the kernel source tree that
  contains them, so that clean no longer skips them for a relative O, a
  missing Module.symvers or a missing /lib/modules/$(uname -r)/build,
  and pass a KDIR given on the command line on as an absolute path.
  Both found by Sashiko.
- Patch 2 is unchanged.

v2: https://lore.kernel.org/all/20261103140218.17568-1-sashal@kernel.org/
v1: https://lore.kernel.org/all/20261014200154.1365200-1-sashal@kernel.org/

Sasha Levin (2):
  selftests/livepatch: build test modules against the selected kernel
  selftests/livepatch: skip based on the test modules instead of KDIR

 tools/testing/selftests/livepatch/Makefile    | 28 +++++++++++++++++++
 .../testing/selftests/livepatch/functions.sh  | 17 ++++-------
 .../selftests/livepatch/test_modules/Makefile | 11 ++++----
 3 files changed, 40 insertions(+), 16 deletions(-)

-- 
2.53.0