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Date:   Fri, 17 Sep 2021 08:54:44 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Brendan Higgins <brendanhiggins@google.com>
Cc:     shuah@kernel.org, davidgow@google.com, arnd@arndb.de,
        rafael@kernel.org, jic23@kernel.org, lars@metafoo.de,
        ulf.hansson@linaro.org, andreas.noever@gmail.com,
        michael.jamet@intel.com, mika.westerberg@linux.intel.com,
        YehezkelShB@gmail.com, masahiroy@kernel.org,
        michal.lkml@markovi.net, ndesaulniers@google.com,
        linux-kselftest@vger.kernel.org, kunit-dev@googlegroups.com,
        linux-kernel@vger.kernel.org, torvalds@linux-foundation.org,
        gregkh@linuxfoundation.org, linux-iio@vger.kernel.org,
        linux-mmc@vger.kernel.org, linux-usb@vger.kernel.org,
        linux-hardening@vger.kernel.org, linux-kbuild@vger.kernel.org
Subject: Re: [PATCH v1 2/6] iio/test-format: build kunit tests without
 structleak plugin
Message-ID: <202109170851.4485B94148@keescook>
References: <20210917061104.2680133-1-brendanhiggins@google.com>
 <20210917061104.2680133-3-brendanhiggins@google.com>
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On Thu, Sep 16, 2021 at 11:11:00PM -0700, Brendan Higgins wrote:
> The structleak plugin causes the stack frame size to grow immensely when
> used with KUnit:
> 
> ../drivers/iio/test/iio-test-format.c: In function ‘iio_test_iio_format_value_fixedpoint’:
> ../drivers/iio/test/iio-test-format.c:98:1: warning: the frame size of 2336 bytes is larger than 2048 bytes [-Wframe-larger-than=]
> 
> Turn it off in this file.

Given that these are all for KUnit tests, is it possible there are going
to be other CONFIGs that will interact poorly (e.g. KASAN)? Maybe there
needs to be a small level of indirection with something like:

DISABLE_UNDER_KUNIT := $(DISABLE_STRUCTLEAK_PLUGIN)
export DISABLE_UNDER_KUNIT

then all of these become:

+CFLAGS_iio-test-format.o += $(DISABLE_UNDER_KUNIT)

Either way, I think these are fine to add.

Reviewed-by: Kees Cook <keescook@chromium.org>


> 
> Co-developed-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
> ---
>  drivers/iio/test/Makefile | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/iio/test/Makefile b/drivers/iio/test/Makefile
> index f1099b4953014..467519a2027e5 100644
> --- a/drivers/iio/test/Makefile
> +++ b/drivers/iio/test/Makefile
> @@ -5,3 +5,4 @@
>  
>  # Keep in alphabetical order
>  obj-$(CONFIG_IIO_TEST_FORMAT) += iio-test-format.o
> +CFLAGS_iio-test-format.o += $(DISABLE_STRUCTLEAK_PLUGIN)
> -- 
> 2.33.0.464.g1972c5931b-goog
> 

-- 
Kees Cook