lkml.org 
[lkml]   [2021]   [Jun]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH v2] kasan: test: Improve failure message in KUNIT_EXPECT_KASAN_FAIL()
On Sat, Jun 5, 2021 at 6:48 AM 'David Gow' via kasan-dev
<kasan-dev@googlegroups.com> wrote:
>
> The KUNIT_EXPECT_KASAN_FAIL() macro currently uses KUNIT_EXPECT_EQ() to
> compare fail_data.report_expected and fail_data.report_found. This
> always gave a somewhat useless error message on failure, but the
> addition of extra compile-time checking with READ_ONCE() has caused it
> to get much longer, and be truncated before anything useful is displayed.
>
> Instead, just check fail_data.report_found by hand (we've just set
> report_expected to 'true'), and print a better failure message with
> KUNIT_FAIL(). Because of this, report_expected is no longer used
> anywhere, and can be removed.
>
> Beforehand, a failure in:
> KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)area)[3100]);
> would have looked like:
> [22:00:34] [FAILED] vmalloc_oob
> [22:00:34] # vmalloc_oob: EXPECTATION FAILED at lib/test_kasan.c:991
> [22:00:34] Expected ({ do { extern void __compiletime_assert_705(void) __attribute__((__error__("Unsupported access size for {READ,WRITE}_ONCE()."))); if (!((sizeof(fail_data.report_expected) == sizeof(char) || sizeof(fail_data.repp
> [22:00:34] not ok 45 - vmalloc_oob
>
> With this change, it instead looks like:
> [22:04:04] [FAILED] vmalloc_oob
> [22:04:04] # vmalloc_oob: EXPECTATION FAILED at lib/test_kasan.c:993
> [22:04:04] KASAN failure expected in "((volatile char *)area)[3100]", but none occurred
> [22:04:04] not ok 45 - vmalloc_oob
>
> Signed-off-by: David Gow <davidgow@google.com>

Hi David,

Please also update the failure message in Documentation/dev-tools/kasan.rst.

Thank you!

> ---
> Changes since v1:
> https://groups.google.com/g/kasan-dev/c/CbabdwoXGlE
> - Remove fail_data.report_expected now that it's unused.
> - Use '!' instead of '== false' in the comparison.
> - Minor typo fixes in the commit message.
>
> The test failure being used as an example is tracked in:
> https://bugzilla.kernel.org/show_bug.cgi?id=213335
>
> Cheers,
> -- David
>
> include/linux/kasan.h | 1 -
> lib/test_kasan.c | 11 +++++------
> 2 files changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> index b1678a61e6a7..18cd5ec2f469 100644
> --- a/include/linux/kasan.h
> +++ b/include/linux/kasan.h
> @@ -17,7 +17,6 @@ struct task_struct;
>
> /* kasan_data struct is used in KUnit tests for KASAN expected failures */
> struct kunit_kasan_expectation {
> - bool report_expected;
> bool report_found;
> };
>
> diff --git a/lib/test_kasan.c b/lib/test_kasan.c
> index cacbbbdef768..44e08f4d9c52 100644
> --- a/lib/test_kasan.c
> +++ b/lib/test_kasan.c
> @@ -55,7 +55,6 @@ static int kasan_test_init(struct kunit *test)
> multishot = kasan_save_enable_multi_shot();
> kasan_set_tagging_report_once(false);
> fail_data.report_found = false;
> - fail_data.report_expected = false;
> kunit_add_named_resource(test, NULL, NULL, &resource,
> "kasan_data", &fail_data);
> return 0;
> @@ -94,20 +93,20 @@ static void kasan_test_exit(struct kunit *test)
> !kasan_async_mode_enabled()) \
> migrate_disable(); \
> KUNIT_EXPECT_FALSE(test, READ_ONCE(fail_data.report_found)); \
> - WRITE_ONCE(fail_data.report_expected, true); \
> barrier(); \
> expression; \
> barrier(); \
> - KUNIT_EXPECT_EQ(test, \
> - READ_ONCE(fail_data.report_expected), \
> - READ_ONCE(fail_data.report_found)); \
> + if (!READ_ONCE(fail_data.report_found)) { \
> + KUNIT_FAIL(test, KUNIT_SUBTEST_INDENT "KASAN failure " \
> + "expected in \"" #expression \
> + "\", but none occurred"); \
> + } \
> if (IS_ENABLED(CONFIG_KASAN_HW_TAGS)) { \
> if (READ_ONCE(fail_data.report_found)) \
> kasan_enable_tagging_sync(); \
> migrate_enable(); \
> } \
> WRITE_ONCE(fail_data.report_found, false); \
> - WRITE_ONCE(fail_data.report_expected, false); \
> } while (0)
>
> #define KASAN_TEST_NEEDS_CONFIG_ON(test, config) do { \
> --
> 2.32.0.rc1.229.g3e70b5a671-goog
>
> --
> You received this message because you are subscribed to the Google Groups "kasan-dev" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to kasan-dev+unsubscribe@googlegroups.com.
> To view this discussion on the web visit https://groups.google.com/d/msgid/kasan-dev/20210605034821.2098034-1-davidgow%40google.com.

\
 
 \ /
  Last update: 2021-06-06 01:25    [W:0.055 / U:0.068 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site