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
Also update the example failure in the documentation to reflect this.
Signed-off-by: David Gow <[email protected]>
---
Changes since v2:
https://lkml.org/lkml/2021/6/4/1264
- Update the example error in the documentation
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
Documentation/dev-tools/kasan.rst | 9 ++++-----
include/linux/kasan.h | 1 -
lib/test_kasan.c | 11 +++++------
3 files changed, 9 insertions(+), 12 deletions(-)
diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst
index d3f335ffc751..83ec4a556c19 100644
--- a/Documentation/dev-tools/kasan.rst
+++ b/Documentation/dev-tools/kasan.rst
@@ -447,11 +447,10 @@ When a test fails due to a failed ``kmalloc``::
When a test fails due to a missing KASAN report::
- # kmalloc_double_kzfree: EXPECTATION FAILED at lib/test_kasan.c:629
- Expected kasan_data->report_expected == kasan_data->report_found, but
- kasan_data->report_expected == 1
- kasan_data->report_found == 0
- not ok 28 - kmalloc_double_kzfree
+ # kmalloc_double_kzfree: EXPECTATION FAILED at lib/test_kasan.c:974
+ KASAN failure expected in "kfree_sensitive(ptr)", but none occurred
+ not ok 44 - kmalloc_double_kzfree
+
At the end the cumulative status of all KASAN tests is printed. On success::
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
On Sun, Jun 6, 2021 at 3:55 AM 'David Gow' via kasan-dev
<[email protected]> 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
>
> Also update the example failure in the documentation to reflect this.
>
> Signed-off-by: David Gow <[email protected]>
> ---
>
> Changes since v2:
> https://lkml.org/lkml/2021/6/4/1264
> - Update the example error in the documentation
>
> 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
>
>
>
> Documentation/dev-tools/kasan.rst | 9 ++++-----
> include/linux/kasan.h | 1 -
> lib/test_kasan.c | 11 +++++------
> 3 files changed, 9 insertions(+), 12 deletions(-)
>
> diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst
> index d3f335ffc751..83ec4a556c19 100644
> --- a/Documentation/dev-tools/kasan.rst
> +++ b/Documentation/dev-tools/kasan.rst
> @@ -447,11 +447,10 @@ When a test fails due to a failed ``kmalloc``::
>
> When a test fails due to a missing KASAN report::
>
> - # kmalloc_double_kzfree: EXPECTATION FAILED at lib/test_kasan.c:629
> - Expected kasan_data->report_expected == kasan_data->report_found, but
> - kasan_data->report_expected == 1
> - kasan_data->report_found == 0
> - not ok 28 - kmalloc_double_kzfree
> + # kmalloc_double_kzfree: EXPECTATION FAILED at lib/test_kasan.c:974
> + KASAN failure expected in "kfree_sensitive(ptr)", but none occurred
> + not ok 44 - kmalloc_double_kzfree
> +
>
> At the end the cumulative status of all KASAN tests is printed. On success::
>
> 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
Reviewed-by: Andrey Konovalov <[email protected]>
Thanks!
On Sun, 6 Jun 2021 at 11:57, Andrey Konovalov <[email protected]> wrote:
>
> On Sun, Jun 6, 2021 at 3:55 AM 'David Gow' via kasan-dev
> <[email protected]> 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
> >
> > Also update the example failure in the documentation to reflect this.
> >
> > Signed-off-by: David Gow <[email protected]>
> > ---
> >
> > Changes since v2:
> > https://lkml.org/lkml/2021/6/4/1264
> > - Update the example error in the documentation
> >
> > 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
> >
> >
> >
> > Documentation/dev-tools/kasan.rst | 9 ++++-----
> > include/linux/kasan.h | 1 -
> > lib/test_kasan.c | 11 +++++------
> > 3 files changed, 9 insertions(+), 12 deletions(-)
> >
> > diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst
> > index d3f335ffc751..83ec4a556c19 100644
> > --- a/Documentation/dev-tools/kasan.rst
> > +++ b/Documentation/dev-tools/kasan.rst
> > @@ -447,11 +447,10 @@ When a test fails due to a failed ``kmalloc``::
> >
> > When a test fails due to a missing KASAN report::
> >
> > - # kmalloc_double_kzfree: EXPECTATION FAILED at lib/test_kasan.c:629
> > - Expected kasan_data->report_expected == kasan_data->report_found, but
> > - kasan_data->report_expected == 1
> > - kasan_data->report_found == 0
> > - not ok 28 - kmalloc_double_kzfree
> > + # kmalloc_double_kzfree: EXPECTATION FAILED at lib/test_kasan.c:974
> > + KASAN failure expected in "kfree_sensitive(ptr)", but none occurred
> > + not ok 44 - kmalloc_double_kzfree
> > +
> >
> > At the end the cumulative status of all KASAN tests is printed. On success::
> >
> > 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
>
> Reviewed-by: Andrey Konovalov <[email protected]>
Reviewed-by: Marco Elver <[email protected]>
On Sat, Jun 5, 2021 at 5:55 PM David Gow <[email protected]> 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
>
> Also update the example failure in the documentation to reflect this.
>
> Signed-off-by: David Gow <[email protected]>
Nice work!
Acked-by: Brendan Higgins <[email protected]>