[PATCH v6 08/10] kunit: string-stream: Add tests for freeing resource-managed string_stream

Richard Fitzgerald
2023-08-28T10:42:44Z

string_stream_managed_free_test() allocates a resource-managed
string_stream and tests that kunit_free_string_stream() calls
string_stream_destroy().

string_stream_resource_free_test() allocates a resource-managed
string_stream and tests that string_stream_destroy() is called
when the test resources are cleaned up.

The old string_stream_init_test() has been split into two tests,
one for kunit_alloc_string_stream() and the other for
alloc_string_stream().

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
---
Changes since v5:
- Fix memory leak when calling the redirected string_stream_destroy_stub().
---
lib/kunit/string-stream-test.c | 147 +++++++++++++++++++++++++++++++--
lib/kunit/string-stream.c | 3 +
2 files changed, 145 insertions(+), 5 deletions(-)

diff --git a/lib/kunit/string-stream-test.c b/lib/kunit/string-stream-test.c
index 58ba1ef5207f..b759974d9cec 100644
--- a/lib/kunit/string-stream-test.c
+++ b/lib/kunit/string-stream-test.c
@@ -6,17 +6,33 @@
* Author: Brendan Higgins <brendanhiggins@google.com>
*/

+#include <kunit/static_stub.h>
#include <kunit/test.h>
#include <linux/slab.h>

#include "string-stream.h"

-/* This avoids a cast warning if kfree() is passed direct to kunit_add_action(). */
+struct string_stream_test_priv {
+ /* For testing resource-managed free. */
+ struct string_stream *expected_free_stream;
+ bool stream_was_freed;
+ bool stream_free_again;
+};
+
+/* Avoids a cast warning if kfree() is passed direct to kunit_add_action(). */
static void kfree_wrapper(void *p)
{
kfree(p);
}

+/* Avoids a cast warning if string_stream_destroy() is passed direct to kunit_add_action(). */
+static void cleanup_raw_stream(void *p)
+{
+ struct string_stream *stream = p;
+
+ string_stream_destroy(stream);
+}
+
static char *get_concatenated_string(struct kunit *test, struct string_stream *stream)
{
char *str = string_stream_get_string(stream);
@@ -27,11 +43,12 @@ static char *get_concatenated_string(struct kunit *test, struct string_stream *s
return str;
}

-/* string_stream object is initialized correctly. */
-static void string_stream_init_test(struct kunit *test)
+/* Managed string_stream object is initialized correctly. */
+static void string_stream_managed_init_test(struct kunit *test)
{
struct string_stream *stream;

+ /* Resource-managed initialization. */
stream = kunit_alloc_string_stream(test, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream);

@@ -42,6 +59,109 @@ static void string_stream_init_test(struct kunit *test)
KUNIT_EXPECT_TRUE(test, string_stream_is_empty(stream));
}

+/* Unmanaged string_stream object is initialized correctly. */
+static void string_stream_unmanaged_init_test(struct kunit *test)
+{
+ struct string_stream *stream;
+
+ stream = alloc_string_stream(GFP_KERNEL);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream);
+ kunit_add_action(test, cleanup_raw_stream, stream);
+
+ KUNIT_EXPECT_EQ(test, stream->length, 0);
+ KUNIT_EXPECT_TRUE(test, list_empty(&stream->fragments));
+ KUNIT_EXPECT_EQ(test, stream->gfp, GFP_KERNEL);
+ KUNIT_EXPECT_FALSE(test, stream->append_newlines);
+
+ KUNIT_EXPECT_TRUE(test, string_stream_is_empty(stream));
+}
+
+static void string_stream_destroy_stub(struct string_stream *stream)
+{
+ struct kunit *fake_test = kunit_get_current_test();
+ struct string_stream_test_priv *priv = fake_test->priv;
+
+ /* The kunit could own string_streams other than the one we are testing. */
+ if (stream == priv->expected_free_stream) {
+ if (priv->stream_was_freed)
+ priv->stream_free_again = true;
+ else
+ priv->stream_was_freed = true;
+ }
+
+ /*
+ * Calling string_stream_destroy() will only call this function again
+ * because the redirection stub is still active.
+ * Avoid calling deactivate_static_stub() or changing current->kunit_test
+ * during cleanup.
+ */
+ string_stream_clear(stream);
+ kfree(stream);
+}
+
+/* kunit_free_string_stream() calls string_stream_desrtoy() */
+static void string_stream_managed_free_test(struct kunit *test)
+{
+ struct string_stream_test_priv *priv = test->priv;
+
+ priv->expected_free_stream = NULL;
+ priv->stream_was_freed = false;
+ priv->stream_free_again = false;
+
+ kunit_activate_static_stub(test,
+ string_stream_destroy,
+ string_stream_destroy_stub);
+
+ priv->expected_free_stream = kunit_alloc_string_stream(test, GFP_KERNEL);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->expected_free_stream);
+
+ /* This should call the stub function. */
+ kunit_free_string_stream(test, priv->expected_free_stream);
+
+ KUNIT_EXPECT_TRUE(test, priv->stream_was_freed);
+ KUNIT_EXPECT_FALSE(test, priv->stream_free_again);
+}
+
+/* string_stream object is freed when test is cleaned up. */
+static void string_stream_resource_free_test(struct kunit *test)
+{
+ struct string_stream_test_priv *priv = test->priv;
+ struct kunit *fake_test;
+
+ fake_test = kunit_kzalloc(test, sizeof(*fake_test), GFP_KERNEL);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, fake_test);
+
+ kunit_init_test(fake_test, "string_stream_fake_test", NULL);
+ fake_test->priv = priv;
+
+ /*
+ * Activate stub before creating string_stream so the
+ * string_stream will be cleaned up first.
+ */
+ priv->expected_free_stream = NULL;
+ priv->stream_was_freed = false;
+ priv->stream_free_again = false;
+
+ kunit_activate_static_stub(fake_test,
+ string_stream_destroy,
+ string_stream_destroy_stub);
+
+ priv->expected_free_stream = kunit_alloc_string_stream(fake_test, GFP_KERNEL);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->expected_free_stream);
+
+ /* Set current->kunit_test to fake_test so the static stub will be called. */
+ current->kunit_test = fake_test;
+
+ /* Cleanup test - the stub function should be called */
+ kunit_cleanup(fake_test);
+
+ /* Set current->kunit_test back to current test. */
+ current->kunit_test = test;
+
+ KUNIT_EXPECT_TRUE(test, priv->stream_was_freed);
+ KUNIT_EXPECT_FALSE(test, priv->stream_free_again);
+}
+
/*
* Add a series of lines to a string_stream. Check that all lines
* appear in the correct order and no characters are dropped.
@@ -334,8 +454,24 @@ static void string_stream_auto_newline_test(struct kunit *test)
"One\nTwo\nThree\nFour\nFive\nSix\nSeven\n\nEight\n");
}

+static int string_stream_test_init(struct kunit *test)
+{
+ struct string_stream_test_priv *priv;
+
+ priv = kunit_kzalloc(test, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ test->priv = priv;
+
+ return 0;
+}
+
static struct kunit_case string_stream_test_cases[] = {
- KUNIT_CASE(string_stream_init_test),
+ KUNIT_CASE(string_stream_managed_init_test),
+ KUNIT_CASE(string_stream_unmanaged_init_test),
+ KUNIT_CASE(string_stream_managed_free_test),
+ KUNIT_CASE(string_stream_resource_free_test),
KUNIT_CASE(string_stream_line_add_test),
KUNIT_CASE(string_stream_variable_length_line_test),
KUNIT_CASE(string_stream_append_test),
@@ -348,6 +484,7 @@ static struct kunit_case string_stream_test_cases[] = {

static struct kunit_suite string_stream_test_suite = {
.name = "string-stream-test",
- .test_cases = string_stream_test_cases
+ .test_cases = string_stream_test_cases,
+ .init = string_stream_test_init,
};
kunit_test_suites(&string_stream_test_suite);
diff --git a/lib/kunit/string-stream.c b/lib/kunit/string-stream.c
index 64abceb7b716..a6f3616c2048 100644
--- a/lib/kunit/string-stream.c
+++ b/lib/kunit/string-stream.c
@@ -6,6 +6,7 @@
* Author: Brendan Higgins <brendanhiggins@google.com>
*/

+#include <kunit/static_stub.h>
#include <kunit/test.h>
#include <linux/list.h>
#include <linux/slab.h>
@@ -170,6 +171,8 @@ struct string_stream *alloc_string_stream(gfp_t gfp)

void string_stream_destroy(struct string_stream *stream)
{
+ KUNIT_STATIC_STUB_REDIRECT(string_stream_destroy, stream);
+
if (!stream)
return;

--
2.30.2