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author | 2020-07-03 15:40:31 +0200 | |
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committer | 2020-08-24 15:09:31 -0700 | |
commit | f9ea63193135473ed6b6ff06f016eb6248100041 (patch) | |
tree | 2d2ce4130259dfe130f8cbe6cc5b60687017340c /kernel/kcsan | |
parent | objtool: Add atomic builtin TSAN instrumentation to uaccess whitelist (diff) | |
download | linux-f9ea63193135473ed6b6ff06f016eb6248100041.tar.gz linux-f9ea63193135473ed6b6ff06f016eb6248100041.tar.bz2 linux-f9ea63193135473ed6b6ff06f016eb6248100041.zip |
kcsan: Add atomic builtin test case
Adds test case to kcsan-test module, to test atomic builtin
instrumentation works.
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/kcsan')
-rw-r--r-- | kernel/kcsan/kcsan-test.c | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/kernel/kcsan/kcsan-test.c b/kernel/kcsan/kcsan-test.c index fed6fcb5768c..721180cbbab1 100644 --- a/kernel/kcsan/kcsan-test.c +++ b/kernel/kcsan/kcsan-test.c @@ -390,6 +390,15 @@ static noinline void test_kernel_seqlock_writer(void) write_sequnlock_irqrestore(&test_seqlock, flags); } +static noinline void test_kernel_atomic_builtins(void) +{ + /* + * Generate concurrent accesses, expecting no reports, ensuring KCSAN + * treats builtin atomics as actually atomic. + */ + __atomic_load_n(&test_var, __ATOMIC_RELAXED); +} + /* ===== Test cases ===== */ /* Simple test with normal data race. */ @@ -853,6 +862,59 @@ static void test_seqlock_noreport(struct kunit *test) } /* + * Test atomic builtins work and required instrumentation functions exist. We + * also test that KCSAN understands they're atomic by racing with them via + * test_kernel_atomic_builtins(), and expect no reports. + * + * The atomic builtins _SHOULD NOT_ be used in normal kernel code! + */ +static void test_atomic_builtins(struct kunit *test) +{ + bool match_never = false; + + begin_test_checks(test_kernel_atomic_builtins, test_kernel_atomic_builtins); + do { + long tmp; + + kcsan_enable_current(); + + __atomic_store_n(&test_var, 42L, __ATOMIC_RELAXED); + KUNIT_EXPECT_EQ(test, 42L, __atomic_load_n(&test_var, __ATOMIC_RELAXED)); + + KUNIT_EXPECT_EQ(test, 42L, __atomic_exchange_n(&test_var, 20, __ATOMIC_RELAXED)); + KUNIT_EXPECT_EQ(test, 20L, test_var); + + tmp = 20L; + KUNIT_EXPECT_TRUE(test, __atomic_compare_exchange_n(&test_var, &tmp, 30L, + 0, __ATOMIC_RELAXED, + __ATOMIC_RELAXED)); + KUNIT_EXPECT_EQ(test, tmp, 20L); + KUNIT_EXPECT_EQ(test, test_var, 30L); + KUNIT_EXPECT_FALSE(test, __atomic_compare_exchange_n(&test_var, &tmp, 40L, + 1, __ATOMIC_RELAXED, + __ATOMIC_RELAXED)); + KUNIT_EXPECT_EQ(test, tmp, 30L); + KUNIT_EXPECT_EQ(test, test_var, 30L); + + KUNIT_EXPECT_EQ(test, 30L, __atomic_fetch_add(&test_var, 1, __ATOMIC_RELAXED)); + KUNIT_EXPECT_EQ(test, 31L, __atomic_fetch_sub(&test_var, 1, __ATOMIC_RELAXED)); + KUNIT_EXPECT_EQ(test, 30L, __atomic_fetch_and(&test_var, 0xf, __ATOMIC_RELAXED)); + KUNIT_EXPECT_EQ(test, 14L, __atomic_fetch_xor(&test_var, 0xf, __ATOMIC_RELAXED)); + KUNIT_EXPECT_EQ(test, 1L, __atomic_fetch_or(&test_var, 0xf0, __ATOMIC_RELAXED)); + KUNIT_EXPECT_EQ(test, 241L, __atomic_fetch_nand(&test_var, 0xf, __ATOMIC_RELAXED)); + KUNIT_EXPECT_EQ(test, -2L, test_var); + + __atomic_thread_fence(__ATOMIC_SEQ_CST); + __atomic_signal_fence(__ATOMIC_SEQ_CST); + + kcsan_disable_current(); + + match_never = report_available(); + } while (!end_test_checks(match_never)); + KUNIT_EXPECT_FALSE(test, match_never); +} + +/* * Each test case is run with different numbers of threads. Until KUnit supports * passing arguments for each test case, we encode #threads in the test case * name (read by get_num_threads()). [The '-' was chosen as a stylistic @@ -891,6 +953,7 @@ static struct kunit_case kcsan_test_cases[] = { KCSAN_KUNIT_CASE(test_assert_exclusive_access_scoped), KCSAN_KUNIT_CASE(test_jiffies_noreport), KCSAN_KUNIT_CASE(test_seqlock_noreport), + KCSAN_KUNIT_CASE(test_atomic_builtins), {}, }; |