[PATCH v1 8/8] kunit: Add tests for faults

Mickaël Salaün
2024-02-29T17:04:40Z

The first test checks NULL pointer dereference and make sure it would
result as a failed test.

The second and third tests check that read-only data is indeed read-only
and trying to modify it would result as a failed test.

This kunit_x86_fault test suite is marked as skipped when run on a
non-x86 native architecture. It is then skipped on UML because such
test would result to a kernel panic.

Tested with:
./tools/testing/kunit/kunit.py run --arch x86_64 kunit_x86_fault

Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Cc: Rae Moar <rmoar@google.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
---
lib/kunit/kunit-test.c | 115 ++++++++++++++++++++++++++++++++++++++++-
1 file changed, 114 insertions(+), 1 deletion(-)

diff --git a/lib/kunit/kunit-test.c b/lib/kunit/kunit-test.c
index f7980ef236a3..57d8eff00c66 100644
--- a/lib/kunit/kunit-test.c
+++ b/lib/kunit/kunit-test.c
@@ -10,6 +10,7 @@
#include <kunit/test-bug.h>

#include <linux/device.h>
+#include <linux/init.h>
#include <kunit/device.h>

#include "string-stream.h"
@@ -109,6 +110,117 @@ static struct kunit_suite kunit_try_catch_test_suite = {
.test_cases = kunit_try_catch_test_cases,
};

+#ifdef CONFIG_X86
+
+static void kunit_test_null_dereference(void *data)
+{
+ struct kunit *test = data;
+ int *null = NULL;
+
+ *null = 0;
+
+ KUNIT_FAIL(test, "This line should never be reached\n");
+}
+
+static void kunit_test_fault_null_dereference(struct kunit *test)
+{
+ struct kunit_try_catch_test_context *ctx = test->priv;
+ struct kunit_try_catch *try_catch = ctx->try_catch;
+
+ kunit_try_catch_init(try_catch,
+ test,
+ kunit_test_null_dereference,
+ kunit_test_catch);
+ kunit_try_catch_run(try_catch, test);
+
+ KUNIT_EXPECT_EQ(test, try_catch->try_result, -EINTR);
+ KUNIT_EXPECT_TRUE(test, ctx->function_called);
+}
+
+#if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
+
+const int test_const = 1;
+
+static void kunit_test_const(void *data)
+{
+ struct kunit *test = data;
+ /* Bypasses compiler check. */
+ int *ptr = (int *)&test_const;
+
+ KUNIT_EXPECT_EQ(test, test_const, 1);
+ *ptr = 2;
+
+ KUNIT_FAIL(test, "This line should never be reached\n");
+}
+
+static void kunit_test_fault_const(struct kunit *test)
+{
+ struct kunit_try_catch_test_context *ctx = test->priv;
+ struct kunit_try_catch *try_catch = ctx->try_catch;
+
+ kunit_try_catch_init(try_catch, test, kunit_test_const,
+ kunit_test_catch);
+ kunit_try_catch_run(try_catch, test);
+
+ KUNIT_EXPECT_EQ(test, test_const, 1);
+ KUNIT_EXPECT_EQ(test, try_catch->try_result, -EINTR);
+ KUNIT_EXPECT_TRUE(test, ctx->function_called);
+}
+
+static int test_rodata __ro_after_init = 1;
+
+static void kunit_test_rodata(void *data)
+{
+ struct kunit *test = data;
+
+ KUNIT_EXPECT_EQ(test, test_rodata, 1);
+ test_rodata = 2;
+
+ KUNIT_FAIL(test, "This line should never be reached\n");
+}
+
+static void kunit_test_fault_rodata(struct kunit *test)
+{
+ struct kunit_try_catch_test_context *ctx = test->priv;
+ struct kunit_try_catch *try_catch = ctx->try_catch;
+
+ if (!rodata_enabled)
+ kunit_skip(test, "Strict RWX is not enabled");
+
+ kunit_try_catch_init(try_catch, test, kunit_test_rodata,
+ kunit_test_catch);
+ kunit_try_catch_run(try_catch, test);
+
+ KUNIT_EXPECT_EQ(test, test_rodata, 1);
+ KUNIT_EXPECT_EQ(test, try_catch->try_result, -EINTR);
+ KUNIT_EXPECT_TRUE(test, ctx->function_called);
+}
+
+#else /* defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX) */
+
+static void kunit_test_fault_rodata(struct kunit *test)
+{
+ kunit_skip(test, "Strict RWX is not supported");
+}
+
+#endif /* defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX) */
+#endif /* CONFIG_X86 */
+
+static struct kunit_case kunit_x86_fault_test_cases[] = {
+#ifdef CONFIG_X86
+ KUNIT_CASE(kunit_test_fault_null_dereference),
+ KUNIT_CASE(kunit_test_fault_const),
+ KUNIT_CASE(kunit_test_fault_rodata),
+#endif /* CONFIG_X86 */
+ {}
+};
+
+static struct kunit_suite kunit_x86_fault_test_suite = {
+ .name = "kunit_x86_fault",
+ .init = kunit_try_catch_test_init,
+ .test_cases = kunit_x86_fault_test_cases,
+};
+
/*
* Context for testing test managed resources
* is_resource_initialized is used to test arbitrary resources
@@ -826,6 +938,7 @@ static struct kunit_suite kunit_current_test_suite = {

kunit_test_suites(&kunit_try_catch_test_suite, &kunit_resource_test_suite,
&kunit_log_test_suite, &kunit_status_test_suite,
- &kunit_current_test_suite, &kunit_device_test_suite);
+ &kunit_current_test_suite, &kunit_device_test_suite,
+ &kunit_x86_fault_test_suite);

MODULE_LICENSE("GPL v2");
--
2.44.0