kunit: Print last test location on fault

This helps identify the location of test faults with opportunistic calls
to _KUNIT_SAVE_LOC().  This can be useful while writing tests or
debugging them.  It is possible to call KUNIT_SUCCESS() to explicit save
last location.

Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Cc: Rae Moar <rmoar@google.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Link: https://lore.kernel.org/r/20240408074625.65017-7-mic@digikod.net
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

diff --git a/include/kunit/test.h b/include/kunit/test.h
index 61637ef323026c8f87112af494eaca70fb963a17..e32b4cb7afa210d0a579cdfe56345a564490725b 100644 (file)
--- a/include/kunit/test.h
+++ b/include/kunit/test.h
@@ -301,6 +301,8 @@ struct kunit {
        struct list_head resources; /* Protected by lock. */
 
        char status_comment[KUNIT_STATUS_COMMENT_SIZE];
+       /* Saves the last seen test. Useful to help with faults. */
+       struct kunit_loc last_seen;
 };
 
 static inline void kunit_set_failure(struct kunit *test)
@@ -567,6 +569,15 @@ void __printf(2, 3) kunit_log_append(struct string_stream *log, const char *fmt,
 #define kunit_err(test, fmt, ...) \
        kunit_printk(KERN_ERR, test, fmt, ##__VA_ARGS__)
 
+/*
+ * Must be called at the beginning of each KUNIT_*_ASSERTION().
+ * Cf. KUNIT_CURRENT_LOC.
+ */
+#define _KUNIT_SAVE_LOC(test) do {                                            \
+       WRITE_ONCE(test->last_seen.file, __FILE__);                            \
+       WRITE_ONCE(test->last_seen.line, __LINE__);                            \
+} while (0)
+
 /**
  * KUNIT_SUCCEED() - A no-op expectation. Only exists for code clarity.
  * @test: The test context object.
@@ -575,7 +586,7 @@ void __printf(2, 3) kunit_log_append(struct string_stream *log, const char *fmt,
  * words, it does nothing and only exists for code clarity. See
  * KUNIT_EXPECT_TRUE() for more information.
  */
-#define KUNIT_SUCCEED(test) do {} while (0)
+#define KUNIT_SUCCEED(test) _KUNIT_SAVE_LOC(test)
 
 void __noreturn __kunit_abort(struct kunit *test);
 
@@ -601,14 +612,16 @@ void __printf(6, 7) __kunit_do_failed_assertion(struct kunit *test,
 } while (0)
 
 
-#define KUNIT_FAIL_ASSERTION(test, assert_type, fmt, ...)                     \
+#define KUNIT_FAIL_ASSERTION(test, assert_type, fmt, ...) do {                \
+       _KUNIT_SAVE_LOC(test);                                                 \
        _KUNIT_FAILED(test,                                                    \
                      assert_type,                                             \
                      kunit_fail_assert,                                       \
                      kunit_fail_assert_format,                                \
                      {},                                                      \
                      fmt,                                                     \
-                     ##__VA_ARGS__)
+                     ##__VA_ARGS__);                                          \
+} while (0)
 
 /**
  * KUNIT_FAIL() - Always causes a test to fail when evaluated.
@@ -637,6 +650,7 @@ void __printf(6, 7) __kunit_do_failed_assertion(struct kunit *test,
                              fmt,                                             \
                              ...)                                             \
 do {                                                                          \
+       _KUNIT_SAVE_LOC(test);                                                 \
        if (likely(!!(condition_) == !!expected_true_))                        \
                break;                                                         \
                                                                               \
@@ -698,6 +712,7 @@ do {                                                                               \
                .right_text = #right,                                          \
        };                                                                     \
                                                                               \
+       _KUNIT_SAVE_LOC(test);                                                 \
        if (likely(__left op __right))                                         \
                break;                                                         \
                                                                               \
@@ -758,6 +773,7 @@ do {                                                                               \
                .right_text = #right,                                          \
        };                                                                     \
                                                                               \
+       _KUNIT_SAVE_LOC(test);                                                 \
        if (likely((__left) && (__right) && (strcmp(__left, __right) op 0)))   \
                break;                                                         \
                                                                               \
@@ -791,6 +807,7 @@ do {                                                                               \
                .right_text = #right,                                          \
        };                                                                     \
                                                                               \
+       _KUNIT_SAVE_LOC(test);                                                 \
        if (likely(__left && __right))                                         \
                if (likely(memcmp(__left, __right, __size) op 0))              \
                        break;                                                 \
@@ -815,6 +832,7 @@ do {                                                                               \
 do {                                                                          \
        const typeof(ptr) __ptr = (ptr);                                       \
                                                                               \
+       _KUNIT_SAVE_LOC(test);                                                 \
        if (!IS_ERR_OR_NULL(__ptr))                                            \
                break;                                                         \
                                                                               \

diff --git a/lib/kunit/try-catch.c b/lib/kunit/try-catch.c
index 7a3910dd78a69670eff429aecde6081827b608b0..fa687278ccc923e1f1a0bd4c900881fc54c70b6c 100644 (file)
--- a/lib/kunit/try-catch.c
+++ b/lib/kunit/try-catch.c
@@ -96,9 +96,13 @@ void kunit_try_catch_run(struct kunit_try_catch *try_catch, void *context)
 
        if (exit_code == -EFAULT)
                try_catch->try_result = 0;
-       else if (exit_code == -EINTR)
-               kunit_err(test, "try faulted\n");
-       else if (exit_code == -ETIMEDOUT)
+       else if (exit_code == -EINTR) {
+               if (test->last_seen.file)
+                       kunit_err(test, "try faulted: last line seen %s:%d\n",
+                                 test->last_seen.file, test->last_seen.line);
+               else
+                       kunit_err(test, "try faulted\n");
+       } else if (exit_code == -ETIMEDOUT)
                kunit_err(test, "try timed out\n");
        else if (exit_code)
                kunit_err(test, "Unknown error: %d\n", exit_code);