From 56b031f0abf55254d47a329010574733fa9a27b8 Mon Sep 17 00:00:00 2001 From: Marco Elver Date: Tue, 16 Jun 2020 14:36:25 +0200 Subject: [PATCH] kcsan: Add jiffies test to test suite Add a test that KCSAN nor the compiler gets confused about accesses to jiffies on different architectures. Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney --- kernel/kcsan/kcsan-test.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/kernel/kcsan/kcsan-test.c b/kernel/kcsan/kcsan-test.c index 3af420ad6ee7..fed6fcb5768c 100644 --- a/kernel/kcsan/kcsan-test.c +++ b/kernel/kcsan/kcsan-test.c @@ -366,6 +366,11 @@ static noinline void test_kernel_read_struct_zero_size(void) kcsan_check_read(&test_struct.val[3], 0); } +static noinline void test_kernel_jiffies_reader(void) +{ + sink_value((long)jiffies); +} + static noinline void test_kernel_seqlock_reader(void) { unsigned int seq; @@ -817,6 +822,23 @@ static void test_assert_exclusive_access_scoped(struct kunit *test) KUNIT_EXPECT_TRUE(test, match_expect_inscope); } +/* + * jiffies is special (declared to be volatile) and its accesses are typically + * not marked; this test ensures that the compiler nor KCSAN gets confused about + * jiffies's declaration on different architectures. + */ +__no_kcsan +static void test_jiffies_noreport(struct kunit *test) +{ + bool match_never = false; + + begin_test_checks(test_kernel_jiffies_reader, test_kernel_jiffies_reader); + do { + match_never = report_available(); + } while (!end_test_checks(match_never)); + KUNIT_EXPECT_FALSE(test, match_never); +} + /* Test that racing accesses in seqlock critical sections are not reported. */ __no_kcsan static void test_seqlock_noreport(struct kunit *test) @@ -867,6 +889,7 @@ static struct kunit_case kcsan_test_cases[] = { KCSAN_KUNIT_CASE(test_assert_exclusive_bits_nochange), KCSAN_KUNIT_CASE(test_assert_exclusive_writer_scoped), KCSAN_KUNIT_CASE(test_assert_exclusive_access_scoped), + KCSAN_KUNIT_CASE(test_jiffies_noreport), KCSAN_KUNIT_CASE(test_seqlock_noreport), {}, };