The patch titled
Subject: kasan: detect false-positives in tests
has been added to the -mm tree. Its filename is
kasan-detect-false-positives-in-tests.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/kasan-detect-false-positives-in-tests.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/kasan-detect-false-positives-in-tests.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: kasan: detect false-positives in tests
Currently, KASAN-KUnit tests can check that a particular annotated part of
code causes a KASAN report. However, they do not check that no unwanted
reports happen between the annotated parts.
This patch implements these checks.
It is done by setting report_data.report_found to false in
kasan_test_init() and at the end of KUNIT_EXPECT_KASAN_FAIL() and then
checking that it remains false at the beginning of
KUNIT_EXPECT_KASAN_FAIL() and in kasan_test_exit().
kunit_add_named_resource() call is moved to kasan_test_init(), and the
value of fail_data.report_expected is kept as false in between
KUNIT_EXPECT_KASAN_FAIL() annotations for consistency.
Link: https://lkml.kernel.org/r/48079c52cc329fbc52f4386996598d58022fb872.1617207873.git.andreyknvl@xxxxxxxxxx
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Reviewed-by: Marco Elver <elver@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/test_kasan.c | 49 +++++++++++++++++++++++++--------------------
1 file changed, 28 insertions(+), 21 deletions(-)
--- a/lib/test_kasan.c~kasan-detect-false-positives-in-tests
+++ a/lib/test_kasan.c
@@ -54,6 +54,10 @@ static int kasan_test_init(struct kunit
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;
}
@@ -61,6 +65,7 @@ static void kasan_test_exit(struct kunit
{
kasan_set_tagging_report_once(true);
kasan_restore_multi_shot(multishot);
+ KUNIT_EXPECT_FALSE(test, fail_data.report_found);
}
/**
@@ -78,28 +83,30 @@ static void kasan_test_exit(struct kunit
* fields, it can reorder or optimize away the accesses to those fields.
* Use READ/WRITE_ONCE() for the accesses and compiler barriers around the
* expression to prevent that.
+ *
+ * In between KUNIT_EXPECT_KASAN_FAIL checks, fail_data.report_found is kept as
+ * false. This allows detecting KASAN reports that happen outside of the checks
+ * by asserting !fail_data.report_found at the start of KUNIT_EXPECT_KASAN_FAIL
+ * and in kasan_test_exit.
*/
-#define KUNIT_EXPECT_KASAN_FAIL(test, expression) do { \
- if (IS_ENABLED(CONFIG_KASAN_HW_TAGS)) \
- migrate_disable(); \
- WRITE_ONCE(fail_data.report_expected, true); \
- WRITE_ONCE(fail_data.report_found, false); \
- kunit_add_named_resource(test, \
- NULL, \
- NULL, \
- &resource, \
- "kasan_data", &fail_data); \
- barrier(); \
- expression; \
- barrier(); \
- KUNIT_EXPECT_EQ(test, \
- READ_ONCE(fail_data.report_expected), \
- READ_ONCE(fail_data.report_found)); \
- if (IS_ENABLED(CONFIG_KASAN_HW_TAGS)) { \
- if (READ_ONCE(fail_data.report_found)) \
- kasan_enable_tagging(); \
- migrate_enable(); \
- } \
+#define KUNIT_EXPECT_KASAN_FAIL(test, expression) do { \
+ if (IS_ENABLED(CONFIG_KASAN_HW_TAGS)) \
+ 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 (IS_ENABLED(CONFIG_KASAN_HW_TAGS)) { \
+ if (READ_ONCE(fail_data.report_found)) \
+ kasan_enable_tagging(); \
+ 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 { \
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
kasan-fix-conflict-with-page-poisoning.patch
kasan-initialize-shadow-to-tag_invalid-for-sw_tags.patch
mm-kasan-dont-poison-boot-memory-with-tag-based-modes.patch
arm64-kasan-allow-to-init-memory-when-setting-tags.patch
kasan-init-memory-in-kasan_unpoison-for-hw_tags.patch
kasan-mm-integrate-page_alloc-init-with-hw_tags.patch
kasan-mm-integrate-page_alloc-init-with-hw_tags-fix.patch
kasan-mm-integrate-slab-init_on_alloc-with-hw_tags.patch
kasan-mm-integrate-slab-init_on_free-with-hw_tags.patch
kasan-docs-clean-up-sections.patch
kasan-docs-update-overview-section.patch
kasan-docs-update-usage-section.patch
kasan-docs-update-error-reports-section.patch
kasan-docs-update-boot-parameters-section.patch
kasan-docs-update-generic-implementation-details-section.patch
kasan-docs-update-sw_tags-implementation-details-section.patch
kasan-docs-update-hw_tags-implementation-details-section.patch
kasan-docs-update-shadow-memory-section.patch
kasan-docs-update-ignoring-accesses-section.patch
kasan-docs-update-tests-section.patch
kasan-detect-false-positives-in-tests.patch
