1 files changed, 93 insertions, 26 deletions

diff --git a/mm/kmsan/kmsan_test.c b/mm/kmsan/kmsan_test.c
index 088e21a48dc4..312989aa2865 100644
--- a/mm/kmsan/kmsan_test.c
+++ b/mm/kmsan/kmsan_test.c
@@ -408,6 +408,37 @@ static void test_printk(struct kunit *test)
 }
 
 /*
+ * Prevent the compiler from optimizing @var away. Without this, Clang may
+ * notice that @var is uninitialized and drop memcpy() calls that use it.
+ *
+ * There is OPTIMIZER_HIDE_VAR() in linux/compier.h that we cannot use here,
+ * because it is implemented as inline assembly receiving @var as a parameter
+ * and will enforce a KMSAN check. Same is true for e.g. barrier_data(var).
+ */
+#define DO_NOT_OPTIMIZE(var) barrier()
+
+/*
+ * Test case: ensure that memcpy() correctly copies initialized values.
+ * Also serves as a regression test to ensure DO_NOT_OPTIMIZE() does not cause
+ * extra checks.
+ */
+static void test_init_memcpy(struct kunit *test)
+{
+	EXPECTATION_NO_REPORT(expect);
+	volatile int src;
+	volatile int dst = 0;
+
+	DO_NOT_OPTIMIZE(src);
+	src = 1;
+	kunit_info(
+		test,
+		"memcpy()ing aligned initialized src to aligned dst (no reports)\n");
+	memcpy((void *)&dst, (void *)&src, sizeof(src));
+	kmsan_check_memory((void *)&dst, sizeof(dst));
+	KUNIT_EXPECT_TRUE(test, report_matches(&expect));
+}
+
+/*
  * Test case: ensure that memcpy() correctly copies uninitialized values between
  * aligned `src` and `dst`.
  */
@@ -420,7 +451,7 @@ static void test_memcpy_aligned_to_aligned(struct kunit *test)
 	kunit_info(
 		test,
 		"memcpy()ing aligned uninit src to aligned dst (UMR report)\n");
-	OPTIMIZER_HIDE_VAR(uninit_src);
+	DO_NOT_OPTIMIZE(uninit_src);
 	memcpy((void *)&dst, (void *)&uninit_src, sizeof(uninit_src));
 	kmsan_check_memory((void *)&dst, sizeof(dst));
 	KUNIT_EXPECT_TRUE(test, report_matches(&expect));
@@ -443,7 +474,7 @@ static void test_memcpy_aligned_to_unaligned(struct kunit *test)
 	kunit_info(
 		test,
 		"memcpy()ing aligned uninit src to unaligned dst (UMR report)\n");
-	OPTIMIZER_HIDE_VAR(uninit_src);
+	DO_NOT_OPTIMIZE(uninit_src);
 	memcpy((void *)&dst[1], (void *)&uninit_src, sizeof(uninit_src));
 	kmsan_check_memory((void *)dst, 4);
 	KUNIT_EXPECT_TRUE(test, report_matches(&expect));
@@ -467,13 +498,33 @@ static void test_memcpy_aligned_to_unaligned2(struct kunit *test)
 	kunit_info(
 		test,
 		"memcpy()ing aligned uninit src to unaligned dst - part 2 (UMR report)\n");
-	OPTIMIZER_HIDE_VAR(uninit_src);
+	DO_NOT_OPTIMIZE(uninit_src);
 	memcpy((void *)&dst[1], (void *)&uninit_src, sizeof(uninit_src));
 	kmsan_check_memory((void *)&dst[4], sizeof(uninit_src));
 	KUNIT_EXPECT_TRUE(test, report_matches(&expect));
 }
 
-static noinline void fibonacci(int *array, int size, int start) {
+/* Generate test cases for memset16(), memset32(), memset64(). */
+#define DEFINE_TEST_MEMSETXX(size)                                          \
+	static void test_memset##size(struct kunit *test)                   \
+	{                                                                   \
+		EXPECTATION_NO_REPORT(expect);                              \
+		volatile uint##size##_t uninit;                             \
+                                                                            \
+		kunit_info(test,                                            \
+			   "memset" #size "() should initialize memory\n"); \
+		DO_NOT_OPTIMIZE(uninit);                                    \
+		memset##size((uint##size##_t *)&uninit, 0, 1);              \
+		kmsan_check_memory((void *)&uninit, sizeof(uninit));        \
+		KUNIT_EXPECT_TRUE(test, report_matches(&expect));           \
+	}
+
+DEFINE_TEST_MEMSETXX(16)
+DEFINE_TEST_MEMSETXX(32)
+DEFINE_TEST_MEMSETXX(64)
+
+static noinline void fibonacci(int *array, int size, int start)
+{
 	if (start < 2 || (start == size))
 		return;
 	array[start] = array[start - 1] + array[start - 2];
@@ -482,8 +533,7 @@ static noinline void fibonacci(int *array, int size, int start) {
 
 static void test_long_origin_chain(struct kunit *test)
 {
-	EXPECTATION_UNINIT_VALUE_FN(expect,
-				    "test_long_origin_chain");
+	EXPECTATION_UNINIT_VALUE_FN(expect, "test_long_origin_chain");
 	/* (KMSAN_MAX_ORIGIN_DEPTH * 2) recursive calls to fibonacci(). */
 	volatile int accum[KMSAN_MAX_ORIGIN_DEPTH * 2 + 2];
 	int last = ARRAY_SIZE(accum) - 1;
@@ -501,6 +551,36 @@ static void test_long_origin_chain(struct kunit *test)
 	KUNIT_EXPECT_TRUE(test, report_matches(&expect));
 }
 
+/*
+ * Test case: ensure that saving/restoring/printing stacks to/from stackdepot
+ * does not trigger errors.
+ *
+ * KMSAN uses stackdepot to store origin stack traces, that's why we do not
+ * instrument lib/stackdepot.c. Yet it must properly mark its outputs as
+ * initialized because other kernel features (e.g. netdev tracker) may also
+ * access stackdepot from instrumented code.
+ */
+static void test_stackdepot_roundtrip(struct kunit *test)
+{
+	unsigned long src_entries[16], *dst_entries;
+	unsigned int src_nentries, dst_nentries;
+	EXPECTATION_NO_REPORT(expect);
+	depot_stack_handle_t handle;
+
+	kunit_info(test, "testing stackdepot roundtrip (no reports)\n");
+
+	src_nentries =
+		stack_trace_save(src_entries, ARRAY_SIZE(src_entries), 1);
+	handle = stack_depot_save(src_entries, src_nentries, GFP_KERNEL);
+	stack_depot_print(handle);
+	dst_nentries = stack_depot_fetch(handle, &dst_entries);
+	KUNIT_EXPECT_TRUE(test, src_nentries == dst_nentries);
+
+	kmsan_check_memory((void *)dst_entries,
+			   sizeof(*dst_entries) * dst_nentries);
+	KUNIT_EXPECT_TRUE(test, report_matches(&expect));
+}
+
 static struct kunit_case kmsan_test_cases[] = {
 	KUNIT_CASE(test_uninit_kmalloc),
 	KUNIT_CASE(test_init_kmalloc),
@@ -515,10 +595,15 @@ static struct kunit_case kmsan_test_cases[] = {
 	KUNIT_CASE(test_uaf),
 	KUNIT_CASE(test_percpu_propagate),
 	KUNIT_CASE(test_printk),
+	KUNIT_CASE(test_init_memcpy),
 	KUNIT_CASE(test_memcpy_aligned_to_aligned),
 	KUNIT_CASE(test_memcpy_aligned_to_unaligned),
 	KUNIT_CASE(test_memcpy_aligned_to_unaligned2),
+	KUNIT_CASE(test_memset16),
+	KUNIT_CASE(test_memset32),
+	KUNIT_CASE(test_memset64),
 	KUNIT_CASE(test_long_origin_chain),
+	KUNIT_CASE(test_stackdepot_roundtrip),
 	{},
 };
 
@@ -541,33 +626,15 @@ static void test_exit(struct kunit *test)
 {
 }
 
-static void register_tracepoints(struct tracepoint *tp, void *ignore)
-{
-	check_trace_callback_type_console(probe_console);
-	if (!strcmp(tp->name, "console"))
-		WARN_ON(tracepoint_probe_register(tp, probe_console, NULL));
-}
-
-static void unregister_tracepoints(struct tracepoint *tp, void *ignore)
-{
-	if (!strcmp(tp->name, "console"))
-		tracepoint_probe_unregister(tp, probe_console, NULL);
-}
-
 static int kmsan_suite_init(struct kunit_suite *suite)
 {
-	/*
-	 * Because we want to be able to build the test as a module, we need to
-	 * iterate through all known tracepoints, since the static registration
-	 * won't work here.
-	 */
-	for_each_kernel_tracepoint(register_tracepoints, NULL);
+	register_trace_console(probe_console, NULL);
 	return 0;
 }
 
 static void kmsan_suite_exit(struct kunit_suite *suite)
 {
-	for_each_kernel_tracepoint(unregister_tracepoints, NULL);
+	unregister_trace_console(probe_console, NULL);
 	tracepoint_synchronize_unregister();
 }