Re: [PATCH] selftests/livepatch: Check if CONFIG_LIVEPATCH is enabled

[Petr Mladek <pmladek@suse.com>]

On Wed 2024-11-06 23:11:20, Siddharth Menon wrote:
> When CONFIG_LIVEPATCH is disabled, compilation fails due to the
> required structs from the livepatch header file being undefined.
> This checks for CONFIG_LIVEPATCH in order to verify that
> it is enabled before compiling livepatch self-tests.
> 
> Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
> Signed-off-by: Siddharth Menon <simeddon@gmail.com>
> ---
>  tools/testing/selftests/livepatch/test_modules/Makefile | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/livepatch/test_modules/Makefile b/tools/testing/selftests/livepatch/test_modules/Makefile
> index e6e638c4bcba..b34b80544709 100644
> --- a/tools/testing/selftests/livepatch/test_modules/Makefile
> +++ b/tools/testing/selftests/livepatch/test_modules/Makefile
> @@ -1,5 +1,6 @@
>  TESTMODS_DIR := $(realpath $(dir $(abspath $(lastword $(MAKEFILE_LIST)))))
>  KDIR ?= /lib/modules/$(shell uname -r)/build
> +CONFIG_LIVEPATCH := $(shell cd $(KDIR) && scripts/config --state CONFIG_LIVEPATCH)
>  
>  obj-m += test_klp_atomic_replace.o \
>  	test_klp_callbacks_busy.o \
> @@ -13,10 +14,15 @@ obj-m += test_klp_atomic_replace.o \
>  	test_klp_shadow_vars.o \
>  	test_klp_syscall.o
>  
> -# Ensure that KDIR exists, otherwise skip the compilation
> +
> +# Ensure that KDIR exists and CONFIG_LIVEPATCH is enabled, else skip compilation
>  modules:
>  ifneq ("$(wildcard $(KDIR))", "")
> +ifneq ($(filter y m,$(CONFIG_LIVEPATCH)),)
>  	$(Q)$(MAKE) -C $(KDIR) modules KBUILD_EXTMOD=$(TESTMODS_DIR)
> +else
> +    $(warning CONFIG_LIVEPATCH is not enabled in the kernel config file.)
> +endif
>  endif

This handles only the build of the modules.

It does not block building the test_klp-call_getpid binary.
Also it does not block running the tests, so I get:

tools/testing/selftests/livepatch # make run_tests 
  CC       test_klp-call_getpid
Makefile:24: CONFIG_LIVEPATCH is not enabled in the kernel config file.
make[1]: Nothing to be done for 'modules'.
TAP version 13
1..7
# timeout set to 0
# selftests: livepatch: test-livepatch.sh
# TEST: basic function patching ... ERROR: Can't find "test_modules/test_klp_livepatch.ko", try "make"
not ok 1 selftests: livepatch: test-livepatch.sh # exit=1
# timeout set to 0
# selftests: livepatch: test-callbacks.sh
# TEST: target module before livepatch ... ERROR: Can't find "test_modules/test_klp_callbacks_mod.ko", try "make"
not ok 2 selftests: livepatch: test-callbacks.sh # exit=1
...


I like idea mentioned in Miroslav's reply. I wonder if the check
could take into account all CONFIG_* variables mentioned
in tools/testing/selftests/livepatch/config.

And if it could be generic so that it works for all
tools/testing/selftests/<project> directories.

And for both build and run_tests.

Best Regards,
Petr