* [PATCH v2] kasan: test: Improve failure message in KUNIT_EXPECT_KASAN_FAIL()
@ 2021-06-05 3:48 David Gow
2021-06-05 23:25 ` Andrey Konovalov
0 siblings, 1 reply; 2+ messages in thread
From: David Gow @ 2021-06-05 3:48 UTC (permalink / raw)
To: Andrey Ryabinin, Dmitry Vyukov, Daniel Axtens, Brendan Higgins
Cc: David Gow, kasan-dev, kunit-dev, linux-kernel
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>
---
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
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] kasan: test: Improve failure message in KUNIT_EXPECT_KASAN_FAIL()
2021-06-05 3:48 [PATCH v2] kasan: test: Improve failure message in KUNIT_EXPECT_KASAN_FAIL() David Gow
@ 2021-06-05 23:25 ` Andrey Konovalov
0 siblings, 0 replies; 2+ messages in thread
From: Andrey Konovalov @ 2021-06-05 23:25 UTC (permalink / raw)
To: David Gow
Cc: Andrey Ryabinin, Dmitry Vyukov, Daniel Axtens, Brendan Higgins,
kasan-dev, kunit-dev, LKML
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
>
> --
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2021-06-05 3:48 [PATCH v2] kasan: test: Improve failure message in KUNIT_EXPECT_KASAN_FAIL() David Gow
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