diff options
Diffstat (limited to 'kernel/kcsan/kcsan_test.c')
| -rw-r--r-- | kernel/kcsan/kcsan_test.c | 319 |
1 files changed, 319 insertions, 0 deletions
diff --git a/kernel/kcsan/kcsan_test.c b/kernel/kcsan/kcsan_test.c index ec054879201b..5bf94550bcdf 100644 --- a/kernel/kcsan/kcsan_test.c +++ b/kernel/kcsan/kcsan_test.c @@ -16,9 +16,12 @@ #define pr_fmt(fmt) "kcsan_test: " fmt #include <kunit/test.h> +#include <linux/atomic.h> +#include <linux/bitops.h> #include <linux/jiffies.h> #include <linux/kcsan-checks.h> #include <linux/kernel.h> +#include <linux/mutex.h> #include <linux/sched.h> #include <linux/seqlock.h> #include <linux/spinlock.h> @@ -305,6 +308,16 @@ static DEFINE_SEQLOCK(test_seqlock); __no_kcsan static noinline void sink_value(long v) { WRITE_ONCE(test_sink, v); } +/* + * Generates a delay and some accesses that enter the runtime but do not produce + * data races. + */ +static noinline void test_delay(int iter) +{ + while (iter--) + sink_value(READ_ONCE(test_sink)); +} + static noinline void test_kernel_read(void) { sink_value(test_var); } static noinline void test_kernel_write(void) @@ -466,8 +479,219 @@ static noinline void test_kernel_xor_1bit(void) kcsan_nestable_atomic_end(); } +#define TEST_KERNEL_LOCKED(name, acquire, release) \ + static noinline void test_kernel_##name(void) \ + { \ + long *flag = &test_struct.val[0]; \ + long v = 0; \ + if (!(acquire)) \ + return; \ + while (v++ < 100) { \ + test_var++; \ + barrier(); \ + } \ + release; \ + test_delay(10); \ + } + +TEST_KERNEL_LOCKED(with_memorder, + cmpxchg_acquire(flag, 0, 1) == 0, + smp_store_release(flag, 0)); +TEST_KERNEL_LOCKED(wrong_memorder, + cmpxchg_relaxed(flag, 0, 1) == 0, + WRITE_ONCE(*flag, 0)); +TEST_KERNEL_LOCKED(atomic_builtin_with_memorder, + __atomic_compare_exchange_n(flag, &v, 1, 0, __ATOMIC_ACQUIRE, __ATOMIC_RELAXED), + __atomic_store_n(flag, 0, __ATOMIC_RELEASE)); +TEST_KERNEL_LOCKED(atomic_builtin_wrong_memorder, + __atomic_compare_exchange_n(flag, &v, 1, 0, __ATOMIC_RELAXED, __ATOMIC_RELAXED), + __atomic_store_n(flag, 0, __ATOMIC_RELAXED)); + /* ===== Test cases ===== */ +/* + * Tests that various barriers have the expected effect on internal state. Not + * exhaustive on atomic_t operations. Unlike the selftest, also checks for + * too-strict barrier instrumentation; these can be tolerated, because it does + * not cause false positives, but at least we should be aware of such cases. + */ +static void test_barrier_nothreads(struct kunit *test) +{ +#ifdef CONFIG_KCSAN_WEAK_MEMORY + struct kcsan_scoped_access *reorder_access = ¤t->kcsan_ctx.reorder_access; +#else + struct kcsan_scoped_access *reorder_access = NULL; +#endif + arch_spinlock_t arch_spinlock = __ARCH_SPIN_LOCK_UNLOCKED; + DEFINE_SPINLOCK(spinlock); + DEFINE_MUTEX(mutex); + atomic_t dummy; + + KCSAN_TEST_REQUIRES(test, reorder_access != NULL); + KCSAN_TEST_REQUIRES(test, IS_ENABLED(CONFIG_SMP)); + +#define __KCSAN_EXPECT_BARRIER(access_type, barrier, order_before, name) \ + do { \ + reorder_access->type = (access_type) | KCSAN_ACCESS_SCOPED; \ + reorder_access->size = sizeof(test_var); \ + barrier; \ + KUNIT_EXPECT_EQ_MSG(test, reorder_access->size, \ + order_before ? 0 : sizeof(test_var), \ + "improperly instrumented type=(" #access_type "): " name); \ + } while (0) +#define KCSAN_EXPECT_READ_BARRIER(b, o) __KCSAN_EXPECT_BARRIER(0, b, o, #b) +#define KCSAN_EXPECT_WRITE_BARRIER(b, o) __KCSAN_EXPECT_BARRIER(KCSAN_ACCESS_WRITE, b, o, #b) +#define KCSAN_EXPECT_RW_BARRIER(b, o) __KCSAN_EXPECT_BARRIER(KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE, b, o, #b) + + /* Force creating a valid entry in reorder_access first. */ + test_var = 0; + while (test_var++ < 1000000 && reorder_access->size != sizeof(test_var)) + __kcsan_check_read(&test_var, sizeof(test_var)); + KUNIT_ASSERT_EQ(test, reorder_access->size, sizeof(test_var)); + + kcsan_nestable_atomic_begin(); /* No watchpoints in called functions. */ + + KCSAN_EXPECT_READ_BARRIER(mb(), true); + KCSAN_EXPECT_READ_BARRIER(wmb(), false); + KCSAN_EXPECT_READ_BARRIER(rmb(), true); + KCSAN_EXPECT_READ_BARRIER(smp_mb(), true); + KCSAN_EXPECT_READ_BARRIER(smp_wmb(), false); + KCSAN_EXPECT_READ_BARRIER(smp_rmb(), true); + KCSAN_EXPECT_READ_BARRIER(dma_wmb(), false); + KCSAN_EXPECT_READ_BARRIER(dma_rmb(), true); + KCSAN_EXPECT_READ_BARRIER(smp_mb__before_atomic(), true); + KCSAN_EXPECT_READ_BARRIER(smp_mb__after_atomic(), true); + KCSAN_EXPECT_READ_BARRIER(smp_mb__after_spinlock(), true); + KCSAN_EXPECT_READ_BARRIER(smp_store_mb(test_var, 0), true); + KCSAN_EXPECT_READ_BARRIER(smp_load_acquire(&test_var), false); + KCSAN_EXPECT_READ_BARRIER(smp_store_release(&test_var, 0), true); + KCSAN_EXPECT_READ_BARRIER(xchg(&test_var, 0), true); + KCSAN_EXPECT_READ_BARRIER(xchg_release(&test_var, 0), true); + KCSAN_EXPECT_READ_BARRIER(xchg_relaxed(&test_var, 0), false); + KCSAN_EXPECT_READ_BARRIER(cmpxchg(&test_var, 0, 0), true); + KCSAN_EXPECT_READ_BARRIER(cmpxchg_release(&test_var, 0, 0), true); + KCSAN_EXPECT_READ_BARRIER(cmpxchg_relaxed(&test_var, 0, 0), false); + KCSAN_EXPECT_READ_BARRIER(atomic_read(&dummy), false); + KCSAN_EXPECT_READ_BARRIER(atomic_read_acquire(&dummy), false); + KCSAN_EXPECT_READ_BARRIER(atomic_set(&dummy, 0), false); + KCSAN_EXPECT_READ_BARRIER(atomic_set_release(&dummy, 0), true); + KCSAN_EXPECT_READ_BARRIER(atomic_add(1, &dummy), false); + KCSAN_EXPECT_READ_BARRIER(atomic_add_return(1, &dummy), true); + KCSAN_EXPECT_READ_BARRIER(atomic_add_return_acquire(1, &dummy), false); + KCSAN_EXPECT_READ_BARRIER(atomic_add_return_release(1, &dummy), true); + KCSAN_EXPECT_READ_BARRIER(atomic_add_return_relaxed(1, &dummy), false); + KCSAN_EXPECT_READ_BARRIER(atomic_fetch_add(1, &dummy), true); + KCSAN_EXPECT_READ_BARRIER(atomic_fetch_add_acquire(1, &dummy), false); + KCSAN_EXPECT_READ_BARRIER(atomic_fetch_add_release(1, &dummy), true); + KCSAN_EXPECT_READ_BARRIER(atomic_fetch_add_relaxed(1, &dummy), false); + KCSAN_EXPECT_READ_BARRIER(test_and_set_bit(0, &test_var), true); + KCSAN_EXPECT_READ_BARRIER(test_and_clear_bit(0, &test_var), true); + KCSAN_EXPECT_READ_BARRIER(test_and_change_bit(0, &test_var), true); + KCSAN_EXPECT_READ_BARRIER(clear_bit_unlock(0, &test_var), true); + KCSAN_EXPECT_READ_BARRIER(__clear_bit_unlock(0, &test_var), true); + KCSAN_EXPECT_READ_BARRIER(clear_bit_unlock_is_negative_byte(0, &test_var), true); + KCSAN_EXPECT_READ_BARRIER(arch_spin_lock(&arch_spinlock), false); + KCSAN_EXPECT_READ_BARRIER(arch_spin_unlock(&arch_spinlock), true); + KCSAN_EXPECT_READ_BARRIER(spin_lock(&spinlock), false); + KCSAN_EXPECT_READ_BARRIER(spin_unlock(&spinlock), true); + KCSAN_EXPECT_READ_BARRIER(mutex_lock(&mutex), false); + KCSAN_EXPECT_READ_BARRIER(mutex_unlock(&mutex), true); + + KCSAN_EXPECT_WRITE_BARRIER(mb(), true); + KCSAN_EXPECT_WRITE_BARRIER(wmb(), true); + KCSAN_EXPECT_WRITE_BARRIER(rmb(), false); + KCSAN_EXPECT_WRITE_BARRIER(smp_mb(), true); + KCSAN_EXPECT_WRITE_BARRIER(smp_wmb(), true); + KCSAN_EXPECT_WRITE_BARRIER(smp_rmb(), false); + KCSAN_EXPECT_WRITE_BARRIER(dma_wmb(), true); + KCSAN_EXPECT_WRITE_BARRIER(dma_rmb(), false); + KCSAN_EXPECT_WRITE_BARRIER(smp_mb__before_atomic(), true); + KCSAN_EXPECT_WRITE_BARRIER(smp_mb__after_atomic(), true); + KCSAN_EXPECT_WRITE_BARRIER(smp_mb__after_spinlock(), true); + KCSAN_EXPECT_WRITE_BARRIER(smp_store_mb(test_var, 0), true); + KCSAN_EXPECT_WRITE_BARRIER(smp_load_acquire(&test_var), false); + KCSAN_EXPECT_WRITE_BARRIER(smp_store_release(&test_var, 0), true); + KCSAN_EXPECT_WRITE_BARRIER(xchg(&test_var, 0), true); + KCSAN_EXPECT_WRITE_BARRIER(xchg_release(&test_var, 0), true); + KCSAN_EXPECT_WRITE_BARRIER(xchg_relaxed(&test_var, 0), false); + KCSAN_EXPECT_WRITE_BARRIER(cmpxchg(&test_var, 0, 0), true); + KCSAN_EXPECT_WRITE_BARRIER(cmpxchg_release(&test_var, 0, 0), true); + KCSAN_EXPECT_WRITE_BARRIER(cmpxchg_relaxed(&test_var, 0, 0), false); + KCSAN_EXPECT_WRITE_BARRIER(atomic_read(&dummy), false); + KCSAN_EXPECT_WRITE_BARRIER(atomic_read_acquire(&dummy), false); + KCSAN_EXPECT_WRITE_BARRIER(atomic_set(&dummy, 0), false); + KCSAN_EXPECT_WRITE_BARRIER(atomic_set_release(&dummy, 0), true); + KCSAN_EXPECT_WRITE_BARRIER(atomic_add(1, &dummy), false); + KCSAN_EXPECT_WRITE_BARRIER(atomic_add_return(1, &dummy), true); + KCSAN_EXPECT_WRITE_BARRIER(atomic_add_return_acquire(1, &dummy), false); + KCSAN_EXPECT_WRITE_BARRIER(atomic_add_return_release(1, &dummy), true); + KCSAN_EXPECT_WRITE_BARRIER(atomic_add_return_relaxed(1, &dummy), false); + KCSAN_EXPECT_WRITE_BARRIER(atomic_fetch_add(1, &dummy), true); + KCSAN_EXPECT_WRITE_BARRIER(atomic_fetch_add_acquire(1, &dummy), false); + KCSAN_EXPECT_WRITE_BARRIER(atomic_fetch_add_release(1, &dummy), true); + KCSAN_EXPECT_WRITE_BARRIER(atomic_fetch_add_relaxed(1, &dummy), false); + KCSAN_EXPECT_WRITE_BARRIER(test_and_set_bit(0, &test_var), true); + KCSAN_EXPECT_WRITE_BARRIER(test_and_clear_bit(0, &test_var), true); + KCSAN_EXPECT_WRITE_BARRIER(test_and_change_bit(0, &test_var), true); + KCSAN_EXPECT_WRITE_BARRIER(clear_bit_unlock(0, &test_var), true); + KCSAN_EXPECT_WRITE_BARRIER(__clear_bit_unlock(0, &test_var), true); + KCSAN_EXPECT_WRITE_BARRIER(clear_bit_unlock_is_negative_byte(0, &test_var), true); + KCSAN_EXPECT_WRITE_BARRIER(arch_spin_lock(&arch_spinlock), false); + KCSAN_EXPECT_WRITE_BARRIER(arch_spin_unlock(&arch_spinlock), true); + KCSAN_EXPECT_WRITE_BARRIER(spin_lock(&spinlock), false); + KCSAN_EXPECT_WRITE_BARRIER(spin_unlock(&spinlock), true); + KCSAN_EXPECT_WRITE_BARRIER(mutex_lock(&mutex), false); + KCSAN_EXPECT_WRITE_BARRIER(mutex_unlock(&mutex), true); + + KCSAN_EXPECT_RW_BARRIER(mb(), true); + KCSAN_EXPECT_RW_BARRIER(wmb(), true); + KCSAN_EXPECT_RW_BARRIER(rmb(), true); + KCSAN_EXPECT_RW_BARRIER(smp_mb(), true); + KCSAN_EXPECT_RW_BARRIER(smp_wmb(), true); + KCSAN_EXPECT_RW_BARRIER(smp_rmb(), true); + KCSAN_EXPECT_RW_BARRIER(dma_wmb(), true); + KCSAN_EXPECT_RW_BARRIER(dma_rmb(), true); + KCSAN_EXPECT_RW_BARRIER(smp_mb__before_atomic(), true); + KCSAN_EXPECT_RW_BARRIER(smp_mb__after_atomic(), true); + KCSAN_EXPECT_RW_BARRIER(smp_mb__after_spinlock(), true); + KCSAN_EXPECT_RW_BARRIER(smp_store_mb(test_var, 0), true); + KCSAN_EXPECT_RW_BARRIER(smp_load_acquire(&test_var), false); + KCSAN_EXPECT_RW_BARRIER(smp_store_release(&test_var, 0), true); + KCSAN_EXPECT_RW_BARRIER(xchg(&test_var, 0), true); + KCSAN_EXPECT_RW_BARRIER(xchg_release(&test_var, 0), true); + KCSAN_EXPECT_RW_BARRIER(xchg_relaxed(&test_var, 0), false); + KCSAN_EXPECT_RW_BARRIER(cmpxchg(&test_var, 0, 0), true); + KCSAN_EXPECT_RW_BARRIER(cmpxchg_release(&test_var, 0, 0), true); + KCSAN_EXPECT_RW_BARRIER(cmpxchg_relaxed(&test_var, 0, 0), false); + KCSAN_EXPECT_RW_BARRIER(atomic_read(&dummy), false); + KCSAN_EXPECT_RW_BARRIER(atomic_read_acquire(&dummy), false); + KCSAN_EXPECT_RW_BARRIER(atomic_set(&dummy, 0), false); + KCSAN_EXPECT_RW_BARRIER(atomic_set_release(&dummy, 0), true); + KCSAN_EXPECT_RW_BARRIER(atomic_add(1, &dummy), false); + KCSAN_EXPECT_RW_BARRIER(atomic_add_return(1, &dummy), true); + KCSAN_EXPECT_RW_BARRIER(atomic_add_return_acquire(1, &dummy), false); + KCSAN_EXPECT_RW_BARRIER(atomic_add_return_release(1, &dummy), true); + KCSAN_EXPECT_RW_BARRIER(atomic_add_return_relaxed(1, &dummy), false); + KCSAN_EXPECT_RW_BARRIER(atomic_fetch_add(1, &dummy), true); + KCSAN_EXPECT_RW_BARRIER(atomic_fetch_add_acquire(1, &dummy), false); + KCSAN_EXPECT_RW_BARRIER(atomic_fetch_add_release(1, &dummy), true); + KCSAN_EXPECT_RW_BARRIER(atomic_fetch_add_relaxed(1, &dummy), false); + KCSAN_EXPECT_RW_BARRIER(test_and_set_bit(0, &test_var), true); + KCSAN_EXPECT_RW_BARRIER(test_and_clear_bit(0, &test_var), true); + KCSAN_EXPECT_RW_BARRIER(test_and_change_bit(0, &test_var), true); + KCSAN_EXPECT_RW_BARRIER(clear_bit_unlock(0, &test_var), true); + KCSAN_EXPECT_RW_BARRIER(__clear_bit_unlock(0, &test_var), true); + KCSAN_EXPECT_RW_BARRIER(clear_bit_unlock_is_negative_byte(0, &test_var), true); + KCSAN_EXPECT_RW_BARRIER(arch_spin_lock(&arch_spinlock), false); + KCSAN_EXPECT_RW_BARRIER(arch_spin_unlock(&arch_spinlock), true); + KCSAN_EXPECT_RW_BARRIER(spin_lock(&spinlock), false); + KCSAN_EXPECT_RW_BARRIER(spin_unlock(&spinlock), true); + KCSAN_EXPECT_RW_BARRIER(mutex_lock(&mutex), false); + KCSAN_EXPECT_RW_BARRIER(mutex_unlock(&mutex), true); + + kcsan_nestable_atomic_end(); +} + /* Simple test with normal data race. */ __no_kcsan static void test_basic(struct kunit *test) @@ -1039,6 +1263,90 @@ static void test_1bit_value_change(struct kunit *test) KUNIT_EXPECT_TRUE(test, match); } +__no_kcsan +static void test_correct_barrier(struct kunit *test) +{ + struct expect_report expect = { + .access = { + { test_kernel_with_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(KCSAN_ACCESS_WRITE) }, + { test_kernel_with_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(0) }, + }, + }; + bool match_expect = false; + + test_struct.val[0] = 0; /* init unlocked */ + begin_test_checks(test_kernel_with_memorder, test_kernel_with_memorder); + do { + match_expect = report_matches_any_reordered(&expect); + } while (!end_test_checks(match_expect)); + KUNIT_EXPECT_FALSE(test, match_expect); +} + +__no_kcsan +static void test_missing_barrier(struct kunit *test) +{ + struct expect_report expect = { + .access = { + { test_kernel_wrong_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(KCSAN_ACCESS_WRITE) }, + { test_kernel_wrong_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(0) }, + }, + }; + bool match_expect = false; + + test_struct.val[0] = 0; /* init unlocked */ + begin_test_checks(test_kernel_wrong_memorder, test_kernel_wrong_memorder); + do { + match_expect = report_matches_any_reordered(&expect); + } while (!end_test_checks(match_expect)); + if (IS_ENABLED(CONFIG_KCSAN_WEAK_MEMORY)) + KUNIT_EXPECT_TRUE(test, match_expect); + else + KUNIT_EXPECT_FALSE(test, match_expect); +} + +__no_kcsan +static void test_atomic_builtins_correct_barrier(struct kunit *test) +{ + struct expect_report expect = { + .access = { + { test_kernel_atomic_builtin_with_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(KCSAN_ACCESS_WRITE) }, + { test_kernel_atomic_builtin_with_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(0) }, + }, + }; + bool match_expect = false; + + test_struct.val[0] = 0; /* init unlocked */ + begin_test_checks(test_kernel_atomic_builtin_with_memorder, + test_kernel_atomic_builtin_with_memorder); + do { + match_expect = report_matches_any_reordered(&expect); + } while (!end_test_checks(match_expect)); + KUNIT_EXPECT_FALSE(test, match_expect); +} + +__no_kcsan +static void test_atomic_builtins_missing_barrier(struct kunit *test) +{ + struct expect_report expect = { + .access = { + { test_kernel_atomic_builtin_wrong_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(KCSAN_ACCESS_WRITE) }, + { test_kernel_atomic_builtin_wrong_memorder, &test_var, sizeof(test_var), __KCSAN_ACCESS_RW(0) }, + }, + }; + bool match_expect = false; + + test_struct.val[0] = 0; /* init unlocked */ + begin_test_checks(test_kernel_atomic_builtin_wrong_memorder, + test_kernel_atomic_builtin_wrong_memorder); + do { + match_expect = report_matches_any_reordered(&expect); + } while (!end_test_checks(match_expect)); + if (IS_ENABLED(CONFIG_KCSAN_WEAK_MEMORY)) + KUNIT_EXPECT_TRUE(test, match_expect); + else + KUNIT_EXPECT_FALSE(test, match_expect); +} + /* * Generate thread counts for all test cases. Values generated are in interval * [2, 5] followed by exponentially increasing thread counts from 8 to 32. @@ -1088,6 +1396,7 @@ static const void *nthreads_gen_params(const void *prev, char *desc) #define KCSAN_KUNIT_CASE(test_name) KUNIT_CASE_PARAM(test_name, nthreads_gen_params) static struct kunit_case kcsan_test_cases[] = { + KUNIT_CASE(test_barrier_nothreads), KCSAN_KUNIT_CASE(test_basic), KCSAN_KUNIT_CASE(test_concurrent_races), KCSAN_KUNIT_CASE(test_novalue_change), @@ -1112,6 +1421,10 @@ static struct kunit_case kcsan_test_cases[] = { KCSAN_KUNIT_CASE(test_seqlock_noreport), KCSAN_KUNIT_CASE(test_atomic_builtins), KCSAN_KUNIT_CASE(test_1bit_value_change), + KCSAN_KUNIT_CASE(test_correct_barrier), + KCSAN_KUNIT_CASE(test_missing_barrier), + KCSAN_KUNIT_CASE(test_atomic_builtins_correct_barrier), + KCSAN_KUNIT_CASE(test_atomic_builtins_missing_barrier), {}, }; @@ -1176,6 +1489,9 @@ static int test_init(struct kunit *test) observed.nlines = 0; spin_unlock_irqrestore(&observed.lock, flags); + if (strstr(test->name, "nothreads")) + return 0; + if (!torture_init_begin((char *)test->name, 1)) return -EBUSY; @@ -1218,6 +1534,9 @@ static void test_exit(struct kunit *test) struct task_struct **stop_thread; int i; + if (strstr(test->name, "nothreads")) + return; + if (torture_cleanup_begin()) return; |