[PATCH v3 6/7] kunit: Print last test location on fault

From: Mickaël Salaün
Date: Tue Mar 19 2024 - 06:56:06 EST


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@xxxxxxxxxx>
Cc: David Gow <davidgow@xxxxxxxxxx>
Cc: Rae Moar <rmoar@xxxxxxxxxx>
Cc: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Mickaël Salaün <mic@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240319104857.70783-7-mic@xxxxxxxxxxx
---

Changes since v2:
* Extend the commit message according to discussion with David.

Changes since v1:
* Add Kees's Reviewed-by.
---
include/kunit/test.h | 24 +++++++++++++++++++++---
lib/kunit/try-catch.c | 10 +++++++---
2 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/include/kunit/test.h b/include/kunit/test.h
index fcb4a4940ace..f3aa66eb0087 100644
--- 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 __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 __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 7a3910dd78a6..d36e78095fdc 100644
--- 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 after %s:%d\n",
+ test->last_seen.file, test->last_seen.line);
+ else
+ kunit_err(test, "try faulted before the first test\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);
--
2.44.0