Re: [PATCH RESEND v4 1/3] kselftests: lib.mk: Add TEST_GEN_MODS_DIR variable

Joe Lawrence
2024-01-02T22:31:26Z

On Wed, Dec 20, 2023 at 01:53:12PM -0300, Marcos Paulo de Souza wrote:
> Add TEST_GEN_MODS_DIR variable for kselftests. It can point to
> a directory containing kernel modules that will be used by
> selftest scripts.
>
> The modules are built as external modules for the running kernel.
> As a result they are always binary compatible and the same tests
> can be used for older or newer kernels.
>
> The build requires "kernel-devel" package to be installed.
> For example, in the upstream sources, the rpm devel package
> is produced by "make rpm-pkg"
>
> The modules can be built independently by
>
> make -C tools/testing/selftests/livepatch/
>
> or they will be automatically built before running the tests via
>
> make -C tools/testing/selftests/livepatch/ run_tests
>
> Note that they are _not_ built when running the standalone
> tests by calling, for example, ./test-state.sh.
>
> Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
> ---
> Documentation/dev-tools/kselftest.rst | 4 ++++
> tools/testing/selftests/lib.mk | 20 +++++++++++++++-----
> 2 files changed, 19 insertions(+), 5 deletions(-)
>
> diff --git a/Documentation/dev-tools/kselftest.rst b/Documentation/dev-tools/kselftest.rst
> index ab376b316c36..7f3582a67318 100644
> --- a/Documentation/dev-tools/kselftest.rst
> +++ b/Documentation/dev-tools/kselftest.rst
> @@ -245,6 +245,10 @@ Contributing new tests (details)
> TEST_PROGS, TEST_GEN_PROGS mean it is the executable tested by
> default.
>
> + TEST_GEN_MODS_DIR should be used by tests that require modules to be built
> + before the test starts. The variable will contain the name of the directory
> + containing the modules.
> +
> TEST_CUSTOM_PROGS should be used by tests that require custom build
> rules and prevent common build rule use.
>
> diff --git a/tools/testing/selftests/lib.mk b/tools/testing/selftests/lib.mk
> index 118e0964bda9..6c7c5a0112cf 100644
> --- a/tools/testing/selftests/lib.mk
> +++ b/tools/testing/selftests/lib.mk
> @@ -70,12 +70,15 @@ KHDR_INCLUDES := -isystem $(KHDR_DIR)
> # TEST_PROGS are for test shell scripts.
> # TEST_CUSTOM_PROGS and TEST_PROGS will be run by common run_tests
> # and install targets. Common clean doesn't touch them.
> +# TEST_GEN_MODS_DIR is used to specify a directory with modules to be built
> +# before the test executes. These modules are cleaned on the clean target as well.
> TEST_GEN_PROGS := $(patsubst %,$(OUTPUT)/%,$(TEST_GEN_PROGS))
> TEST_GEN_PROGS_EXTENDED := $(patsubst %,$(OUTPUT)/%,$(TEST_GEN_PROGS_EXTENDED))
> TEST_GEN_FILES := $(patsubst %,$(OUTPUT)/%,$(TEST_GEN_FILES))
> +TEST_GEN_MODS_DIR := $(patsubst %,$(OUTPUT)/%,$(TEST_GEN_MODS_DIR))
>
> all: kernel_header_files $(TEST_GEN_PROGS) $(TEST_GEN_PROGS_EXTENDED) \
> - $(TEST_GEN_FILES)
> + $(TEST_GEN_FILES) $(if $(TEST_GEN_MODS_DIR),gen_mods_dir)
>
> kernel_header_files:
> @ls $(KHDR_DIR)/linux/*.h >/dev/null 2>/dev/null; \
> @@ -105,8 +108,8 @@ endef
>
> run_tests: all
> ifdef building_out_of_srctree
> - @if [ "X$(TEST_PROGS)$(TEST_PROGS_EXTENDED)$(TEST_FILES)" != "X" ]; then \
> - rsync -aq --copy-unsafe-links $(TEST_PROGS) $(TEST_PROGS_EXTENDED) $(TEST_FILES) $(OUTPUT); \
> + @if [ "X$(TEST_PROGS)$(TEST_PROGS_EXTENDED)$(TEST_FILES)$(TEST_GEN_MODS_DIR)" != "X" ]; then \
> + rsync -aq --copy-unsafe-links $(TEST_PROGS) $(TEST_PROGS_EXTENDED) $(TEST_FILES) $(TEST_GEN_MODS_DIR) $(OUTPUT); \
> fi
> @if [ "X$(TEST_PROGS)" != "X" ]; then \
> $(call RUN_TESTS, $(TEST_GEN_PROGS) $(TEST_CUSTOM_PROGS) \
> @@ -118,6 +121,12 @@ else
> @$(call RUN_TESTS, $(TEST_GEN_PROGS) $(TEST_CUSTOM_PROGS) $(TEST_PROGS))
> endif
>
> +gen_mods_dir:
> + $(Q)$(MAKE) -C $(TEST_GEN_MODS_DIR)
> +
> +clean_mods_dir:
> + $(Q)$(MAKE) -C $(TEST_GEN_MODS_DIR) clean
> +
> define INSTALL_SINGLE_RULE
> $(if $(INSTALL_LIST),@mkdir -p $(INSTALL_PATH))
> $(if $(INSTALL_LIST),rsync -a --copy-unsafe-links $(INSTALL_LIST) $(INSTALL_PATH)/)
> @@ -131,6 +140,7 @@ define INSTALL_RULE
> $(eval INSTALL_LIST = $(TEST_CUSTOM_PROGS)) $(INSTALL_SINGLE_RULE)
> $(eval INSTALL_LIST = $(TEST_GEN_PROGS_EXTENDED)) $(INSTALL_SINGLE_RULE)
> $(eval INSTALL_LIST = $(TEST_GEN_FILES)) $(INSTALL_SINGLE_RULE)
> + $(eval INSTALL_LIST = $(TEST_GEN_MODS_DIR)) $(INSTALL_SINGLE_RULE)

Hi Marcos,

Sorry for the late reply on this, but I'm reviewing this version by
trying to retrofit it into our selftest packaging (pre-build the test
module .ko's and stash those into an rpm rather than building on the
test host).

Since $TEST_GEN_MODS_DIR is treated as a directory, I found that the
selftest install target copies a bunch of intermediate object and kbuild
files:

$ mkdir /tmp/test-install
$ make KDIR=$(pwd) INSTALL_PATH=/tmp/test-install TARGETS=livepatch \
-C tools/testing/selftests/ install

[ ... builds livepatch selftests ... ]

the rsync in question:

rsync -a --copy-unsafe-links /home/jolawren/src/kernel/tools/testing/selftests/livepatch/test_modules /tmp/test-install/livepatch/
...

and then looking at the destination:

$ tree -a /tmp/test-install/
/tmp/test-install/
├── kselftest
│   ├── module.sh
│   ├── prefix.pl
│   └── runner.sh
├── kselftest-list.txt
├── livepatch
│   ├── config
│   ├── functions.sh
│   ├── settings
│   ├── test-callbacks.sh
│   ├── test-ftrace.sh
│   ├── test_klp-call_getpid
│   ├── test-livepatch.sh
│   ├── test_modules
│   │   ├── Makefile
│   │   ├── modules.order
│   │   ├── .modules.order.cmd
│   │   ├── Module.symvers
│   │   ├── .Module.symvers.cmd
│   │   ├── test_klp_atomic_replace.c
│   │   ├── test_klp_atomic_replace.ko
│   │   ├── .test_klp_atomic_replace.ko.cmd
│   │   ├── test_klp_atomic_replace.mod
│   │   ├── test_klp_atomic_replace.mod.c
│   │   ├── .test_klp_atomic_replace.mod.cmd
│   │   ├── test_klp_atomic_replace.mod.o
│   │   ├── .test_klp_atomic_replace.mod.o.cmd
│   │   ├── test_klp_atomic_replace.o
│   │   ├── .test_klp_atomic_replace.o.cmd
...

On the other hand, variables like $TEST_GEN_FILES specify individual
files, so only final binaries like test_klp-call_getpid (and not
test_klp-call_getpid.c) are copied to $INSTALL_PATH.

Since the selftest module builds appear to ignore
CONFIG_MODULE_COMPRESS_* the smallest tweak I can think of to avoid the
above scenario is:

--- a/tools/testing/selftests/lib.mk
+++ b/tools/testing/selftests/lib.mk
@@ -106,7 +106,7 @@ define INSTALL_RULE
$(eval INSTALL_LIST = $(TEST_CUSTOM_PROGS)) $(INSTALL_SINGLE_RULE)
$(eval INSTALL_LIST = $(TEST_GEN_PROGS_EXTENDED)) $(INSTALL_SINGLE_RULE)
$(eval INSTALL_LIST = $(TEST_GEN_FILES)) $(INSTALL_SINGLE_RULE)
- $(eval INSTALL_LIST = $(TEST_GEN_MODS_DIR)) $(INSTALL_SINGLE_RULE)
+ $(eval INSTALL_LIST = $(shell sed 's/.o$$/.ko/' $(TEST_GEN_MODS_DIR)/modules.order)) $(INSTALL_SINGLE_RULE)
$(eval INSTALL_LIST = $(wildcard config settings)) $(INSTALL_SINGLE_RULE)
endef

However, that will copy .ko's directly into $INSTALL_PATH and out of the
$TEST_GEN_MODS_DIR subdirectory(s), so maybe not a great solution after
all.

Anyway, I thought I might mention this in case it runs against the
spirit of the selftest install target. I only tripped over it while
digging into the bowels of our kernel specfile and discovered that it
invoked this target.

--
Joe