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authorAndrey Konovalov <andreyknvl@google.com>2021-04-29 23:00:49 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-04-30 11:20:42 -0700
commit99734b535d9bf8d5826be8f8f3719dfc586c3452 (patch)
treeb6830f839757840e1b9d26474e9e4549498026f7 /lib
parent23f61f0fe106da8c9f6a883965439ecc2838f116 (diff)
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@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/test_kasan.c55
1 files changed, 29 insertions, 26 deletions
diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 0882d6c17e62..dc05cfc2d12f 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -54,6 +54,10 @@ 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;
}
@@ -61,6 +65,7 @@ static void kasan_test_exit(struct kunit *test)
{
kasan_set_tagging_report_once(true);
kasan_restore_multi_shot(multishot);
+ KUNIT_EXPECT_FALSE(test, fail_data.report_found);
}
/**
@@ -78,33 +83,31 @@ static void kasan_test_exit(struct kunit *test)
* 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) && \
- !kasan_async_mode_enabled()) \
- 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(); \
- if (kasan_async_mode_enabled()) \
- kasan_force_async_fault(); \
- barrier(); \
- KUNIT_EXPECT_EQ(test, \
- READ_ONCE(fail_data.report_expected), \
- READ_ONCE(fail_data.report_found)); \
- if (IS_ENABLED(CONFIG_KASAN_HW_TAGS) && \
- !kasan_async_mode_enabled()) { \
- if (READ_ONCE(fail_data.report_found)) \
- kasan_enable_tagging_sync(); \
- migrate_enable(); \
- } \
+#define KUNIT_EXPECT_KASAN_FAIL(test, expression) do { \
+ if (IS_ENABLED(CONFIG_KASAN_HW_TAGS) && \
+ !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 (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 { \

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