Re: [PATCH] kunit: configs: Enable CONFIG_INIT_STACK_ALL_PATTERN in all_tests

[Jakub Kicinski <kuba@kernel.org>]

On Fri, 11 Apr 2025 10:59:04 +0100 Richard Fitzgerald wrote:
> Enable CONFIG_INIT_STACK_ALL_PATTERN in all_tests.config. This helps
> to detect use of uninitialized local variables.
> 
> This option found an uninitialized data bug in the cs_dsp test.
> 
> Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
> ---
>  tools/testing/kunit/configs/all_tests.config | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/tools/testing/kunit/configs/all_tests.config b/tools/testing/kunit/configs/all_tests.config
> index cdd9782f9646..4a60bb71fe72 100644
> --- a/tools/testing/kunit/configs/all_tests.config
> +++ b/tools/testing/kunit/configs/all_tests.config
> @@ -10,6 +10,7 @@ CONFIG_KUNIT_EXAMPLE_TEST=y
>  CONFIG_KUNIT_ALL_TESTS=y
>  
>  CONFIG_FORTIFY_SOURCE=y
> +CONFIG_INIT_STACK_ALL_PATTERN=y

This breaks kunit for older compilers:

$ ./tools/testing/kunit/kunit.py run  --alltests --json --arch=x86_64 
 Configuring KUnit Kernel ...
 Regenerating .config ...
 Populating config with:
 $ make ARCH=x86_64 O=.kunit olddefconfig
 ERROR:root:Not all Kconfig options selected in kunitconfig were in the generated .config.
 This is probably due to unsatisfied dependencies.
 Missing: CONFIG_INIT_STACK_ALL_PATTERN=y

$ gcc --version
 gcc (GCC) 11.5.0 20240719 (Red Hat 11.5.0-5)

IIUC GCC 11.5 is supported so pattern init can't be a hard requirement.
How about we do this instead? Can you check if it'd work for you?

diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening
index c17366ce8224..904b99f34cd0 100644
--- a/security/Kconfig.hardening
+++ b/security/Kconfig.hardening
@@ -113,6 +113,7 @@ choice
                bool "pattern-init everything (strongest)"
+               default KUNIT_ALL_TESTS
                depends on CC_HAS_AUTO_VAR_INIT_PATTERN
                depends on !KMSAN
                help
                  Initializes everything on the stack (including padding)
                  with a specific debug value. This is intended to eliminate