Re: [PATCH v2] selftests/lkdtm: Disable CONFIG_UBSAN_TRAP in test config

["Ricardo Cañuelo" <ricardo.canuelo@collabora.com>]

Hi Shuah,

Gentle ping for this, what's the merge status?

On mié, ago 02 2023 at 08:32:52, Ricardo Cañuelo <ricardo.canuelo@collabora.com> wrote:
> The lkdtm selftest config fragment enables CONFIG_UBSAN_TRAP to make the
> ARRAY_BOUNDS test kill the calling process when an out-of-bound access
> is detected by UBSAN. However, after this [1] commit, UBSAN is triggered
> under many new scenarios that weren't detected before, such as in struct
> definitions with fixed-size trailing arrays used as flexible arrays. As
> a result, CONFIG_UBSAN_TRAP=y has become a very aggressive option to
> enable except for specific situations.
>
> `make kselftest-merge` applies CONFIG_UBSAN_TRAP=y to the kernel config
> for all selftests, which makes many of them fail because of system hangs
> during boot.
>
> This change removes the config option from the lkdtm kselftest and
> configures the ARRAY_BOUNDS test to look for UBSAN reports rather than
> relying on the calling process being killed.
>
> [1] commit 2d47c6956ab3 ("ubsan: Tighten UBSAN_BOUNDS on GCC")'
>
> Signed-off-by: Ricardo Cañuelo <ricardo.canuelo@collabora.com>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> ---
>
> Changelog:
>
> v2:
>   - Configure the ARRAY_BOUNDS lkdtm test to match UBSAN reports instead
>     of disabling the test
>
>  tools/testing/selftests/lkdtm/config    | 1 -
>  tools/testing/selftests/lkdtm/tests.txt | 2 +-
>  2 files changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/lkdtm/config b/tools/testing/selftests/lkdtm/config
> index 5d52f64dfb43..7afe05e8c4d7 100644
> --- a/tools/testing/selftests/lkdtm/config
> +++ b/tools/testing/selftests/lkdtm/config
> @@ -9,7 +9,6 @@ CONFIG_INIT_ON_FREE_DEFAULT_ON=y
>  CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y
>  CONFIG_UBSAN=y
>  CONFIG_UBSAN_BOUNDS=y
> -CONFIG_UBSAN_TRAP=y
>  CONFIG_STACKPROTECTOR_STRONG=y
>  CONFIG_SLUB_DEBUG=y
>  CONFIG_SLUB_DEBUG_ON=y
> diff --git a/tools/testing/selftests/lkdtm/tests.txt b/tools/testing/selftests/lkdtm/tests.txt
> index 607b8d7e3ea3..2f3a1b96da6e 100644
> --- a/tools/testing/selftests/lkdtm/tests.txt
> +++ b/tools/testing/selftests/lkdtm/tests.txt
> @@ -7,7 +7,7 @@ EXCEPTION
>  #EXHAUST_STACK Corrupts memory on failure
>  #CORRUPT_STACK Crashes entire system on success
>  #CORRUPT_STACK_STRONG Crashes entire system on success
> -ARRAY_BOUNDS
> +ARRAY_BOUNDS call trace:|UBSAN: array-index-out-of-bounds
>  CORRUPT_LIST_ADD list_add corruption
>  CORRUPT_LIST_DEL list_del corruption
>  STACK_GUARD_PAGE_LEADING
> -- 
> 2.25.1

Thanks,
Ricardo