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author | Andrey Konovalov <andreyknvl@google.com> | 2021-04-29 23:00:49 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-04-30 11:20:42 -0700 |
commit | 99734b535d9bf8d5826be8f8f3719dfc586c3452 (patch) | |
tree | b6830f839757840e1b9d26474e9e4549498026f7 /lib | |
parent | 23f61f0fe106da8c9f6a883965439ecc2838f116 (diff) | |
download | linux-99734b535d9bf8d5826be8f8f3719dfc586c3452.tar.gz linux-99734b535d9bf8d5826be8f8f3719dfc586c3452.tar.bz2 linux-99734b535d9bf8d5826be8f8f3719dfc586c3452.zip |
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.c | 55 |
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 { \ |