Re: [PATCH 07/11] kasan: add compiler barriers to KUNIT_EXPECT_KASAN_FAIL

[Marco Elver]

On Tue, Jan 05, 2021 at 07:27PM +0100, Andrey Konovalov wrote:
> It might not be obvious to the compiler that the expression must be
> executed between writing and reading to fail_data. In this case, the
> compiler might reorder or optimize away some of the accesses, and
> the tests will fail.
> 
> Add compiler barriers around the expression in KUNIT_EXPECT_KASAN_FAIL.
> 
> Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
> Link: https://linux-review.googlesource.com/id/I046079f48641a1d36fe627fc8827a9249102fd50

Reviewed-by: Marco Elver <elver@xxxxxxxxxx>

> ---
>  lib/test_kasan.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/lib/test_kasan.c b/lib/test_kasan.c
> index dd3d2f95c24e..b5077a47b95a 100644
> --- a/lib/test_kasan.c
> +++ b/lib/test_kasan.c
> @@ -79,7 +79,9 @@ static void kasan_test_exit(struct kunit *test)
>  				NULL,				\
>  				&resource,			\
>  				"kasan_data", &fail_data);	\
> +	barrier();						\
>  	expression;						\
> +	barrier();						\
>  	KUNIT_EXPECT_EQ(test,					\
>  			fail_data.report_expected,		\
>  			fail_data.report_found);		\
> -- 
> 2.29.2.729.g45daf8777d-goog
>