[Devel] [PATCH RHEL10 COMMIT] selftests: do not hide a missing kernel build tree

[Konstantin Khorenko <khorenko@virtuozzo.com>]

The commit is pushed to "branch-rh10-6.12.0-211.39.1.16.x.vz10-ovz" and will appear at git at bitbucket.org:openvz/vzkernel.git
after rh10-6.12.0-211.39.1.16.4.vz10
------>
commit c07a6860abc51ad6a6f2ac2f2b64d444be88de54
Author: Konstantin Khorenko <khorenko@virtuozzo.com>
Date:   Thu Aug 13 19:20:09 2026 +0200

    selftests: do not hide a missing kernel build tree
    
    The livepatch and cgroup test module Makefiles wrap their recipes into a
    KDIR existence test:
    
            # Ensure that KDIR exists, otherwise skip the compilation
            modules:
            ifneq ("$(wildcard $(KDIR))", "")
                    $(Q)$(MAKE) -C $(KDIR) modules KBUILD_EXTMOD=$(TESTMODS_DIR)
            endif
    
    so the test modules are silently not built when KDIR is not there: the
    target simply loses its recipe and make reports success. The test comes
    from commit 54ee3526796f ("selftests: livepatch: Avoid running the tests
    if kernel-devel is missing"), which was a reaction to a kernel test robot
    build failure report, and the cgroup Makefile copied the pattern later.
    bpf/test_kmods and mm/page_frag never had such a test and simply fail, so
    the tree is not consistent about it either.
    
    A silent skip is the worst possible outcome for a packaged testsuite: the
    test modules are missing from the rpm, the build log says nothing about
    it, and the failure only surfaces on a test node as a test which cannot
    find its module, far away from the cause.
    
    Nothing is lost by dropping it, because the selftests framework already
    implements the "do not fail everything because of one target" policy and
    kernel packaging passes FORCE_TARGETS=1 exactly because it wants to know
    whether every test module has been built:
    
      all:
            @ret=1;                                                 \
            for TARGET in $(TARGETS); do                            \
                    $(MAKE) OUTPUT=$$BUILD_TARGET -C $$TARGET       \
                                    O=$(abs_objtree)                \
                                    $(if $(FORCE_TARGETS),|| exit); \
                    ret=$$((ret * $$?));                            \
            done; exit $$ret;
    
    So drop the tests and let make -C fail and say why. This also puts the
    two Makefiles back in line with bpf/test_kmods and mm/page_frag.
    
    https://virtuozzo.atlassian.net/browse/VSTOR-139647
    Feature: fix selftests
    Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>
---
 tools/testing/selftests/cgroup/test_modules/Makefile    | 6 ------
 tools/testing/selftests/livepatch/test_modules/Makefile | 6 ------
 2 files changed, 12 deletions(-)

diff --git a/tools/testing/selftests/cgroup/test_modules/Makefile b/tools/testing/selftests/cgroup/test_modules/Makefile
index 3f39eeda3a92b..38121d783d921 100644
--- a/tools/testing/selftests/cgroup/test_modules/Makefile
+++ b/tools/testing/selftests/cgroup/test_modules/Makefile
@@ -4,14 +4,8 @@ KDIR ?= /lib/modules/$(shell uname -r)/build
 obj-m += cg_freezer_hang.o \
 	cg_freezer_kthread.o
 
-# Ensure that KDIR exists, otherwise skip the compilation
 modules:
-ifneq ("$(wildcard $(KDIR))", "")
 	$(Q)$(MAKE) -C $(KDIR) modules KBUILD_EXTMOD=$(TESTMODS_DIR)
-endif
 
-# Ensure that KDIR exists, otherwise skip the clean target
 clean:
-ifneq ("$(wildcard $(KDIR))", "")
 	$(Q)$(MAKE) -C $(KDIR) clean KBUILD_EXTMOD=$(TESTMODS_DIR)
-endif
diff --git a/tools/testing/selftests/livepatch/test_modules/Makefile b/tools/testing/selftests/livepatch/test_modules/Makefile
index 939230e571f5d..34e2f76fb4cec 100644
--- a/tools/testing/selftests/livepatch/test_modules/Makefile
+++ b/tools/testing/selftests/livepatch/test_modules/Makefile
@@ -14,14 +14,8 @@ obj-m += test_klp_atomic_replace.o \
 	test_klp_state3.o \
 	test_klp_syscall.o
 
-# Ensure that KDIR exists, otherwise skip the compilation
 modules:
-ifneq ("$(wildcard $(KDIR))", "")
 	$(Q)$(MAKE) -C $(KDIR) modules KBUILD_EXTMOD=$(TESTMODS_DIR)
-endif
 
-# Ensure that KDIR exists, otherwise skip the clean target
 clean:
-ifneq ("$(wildcard $(KDIR))", "")
 	$(Q)$(MAKE) -C $(KDIR) clean KBUILD_EXTMOD=$(TESTMODS_DIR)
-endif