Re: [PATCH v4 08/10] kunit: string-stream: Add test for freeing resource-managed string_stream

[David Gow]

On Mon, 14 Aug 2023 at 21:23, Richard Fitzgerald
<rf@xxxxxxxxxxxxxxxxxxxxx> wrote:
>
> string_stream_resource_free_test() allocates a resource-managed
> string_stream and tests that raw_free_string_stream() is called when
> the test resources are cleaned up.
>
> string_stream_init_test() is extended to test allocating a
> string_stream that is not resource-managed.
>
> Signed-off-by: Richard Fitzgerald <rf@xxxxxxxxxxxxxxxxxxxxx>
> ---

Glad to see this tested. It's nice to see the static_stub being useful
here, too.

Reviewed-by: David Gow <davidgow@xxxxxxxxxx>

Cheers,
-- David

>  lib/kunit/string-stream-test.c | 117 ++++++++++++++++++++++++++++++++-
>  lib/kunit/string-stream.c      |   3 +
>  2 files changed, 119 insertions(+), 1 deletion(-)
>
> diff --git a/lib/kunit/string-stream-test.c b/lib/kunit/string-stream-test.c
> index 437aa4b3179d..05bfade2bd8a 100644
> --- a/lib/kunit/string-stream-test.c
> +++ b/lib/kunit/string-stream-test.c
> @@ -6,16 +6,27 @@
>   * Author: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
>   */
>
> +#include <kunit/static_stub.h>
>  #include <kunit/test.h>
>  #include <linux/slab.h>
>
>  #include "string-stream.h"
>
> +struct string_stream_test_priv {
> +       struct string_stream *raw_stream;
> +
> +       /* For testing resource-managed free */
> +       struct string_stream *freed_stream;
> +       bool stream_free_again;
> +};
> +
>  /* string_stream object is initialized correctly. */
>  static void string_stream_init_test(struct kunit *test)
>  {
> +       struct string_stream_test_priv *priv = test->priv;
>         struct string_stream *stream;
>
> +       /* Resource-managed initialization */
>         stream = alloc_string_stream(test, GFP_KERNEL);
>         KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream);
>
> @@ -26,6 +37,86 @@ static void string_stream_init_test(struct kunit *test)
>         KUNIT_EXPECT_FALSE(test, stream->append_newlines);
>
>         KUNIT_EXPECT_TRUE(test, string_stream_is_empty(stream));
> +
> +       free_string_stream(test, stream);
> +
> +       /*
> +        * Raw initialization. This allocation is not resource-managed
> +        * so store it in priv->raw_stream to be cleaned up by the
> +        * exit function.
> +        */
> +       priv->raw_stream = raw_alloc_string_stream(GFP_KERNEL);
> +       stream = priv->raw_stream;
> +       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream);
> +
> +       KUNIT_EXPECT_EQ(test, stream->length, 0);
> +       KUNIT_EXPECT_TRUE(test, list_empty(&stream->fragments));
> +       KUNIT_EXPECT_PTR_EQ(test, stream->test, NULL);
> +       KUNIT_EXPECT_EQ(test, stream->gfp, GFP_KERNEL);

Again, this will probably annoy sparse, so expect an email from ktr.
We'll look into how to fix this in either KUnit or sparse separately.


> +       KUNIT_EXPECT_FALSE(test, stream->append_newlines);
> +
> +       KUNIT_EXPECT_TRUE(test, string_stream_is_empty(stream));
> +}
> +
> +static void string_stream_raw_free_string_stream_stub(struct string_stream *stream)
> +{
> +       struct kunit *fake_test = kunit_get_current_test();
> +       struct string_stream_test_priv *priv = fake_test->priv;
> +
> +       if (priv->freed_stream)
> +               priv->stream_free_again = true;
> +
> +       priv->freed_stream = stream;
> +
> +       /*
> +        * Avoid calling deactivate_static_stub() or changing
> +        * current->kunit_test during cleanup. Leave the stream to
> +        * be freed during the test exit.
> +        */
> +}
> +
> +/* 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;
> +       struct string_stream *stream;
> +
> +       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->freed_stream = NULL;
> +       priv->stream_free_again = false;
> +       kunit_activate_static_stub(fake_test,
> +                                  raw_free_string_stream,
> +                                  string_stream_raw_free_string_stream_stub);
> +
> +       stream = alloc_string_stream(fake_test, GFP_KERNEL);
> +       KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream);
> +
> +       /*
> +        * Ensure the stream is freed when this test terminates.
> +        */
> +       priv->raw_stream = 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_PTR_EQ(test, priv->freed_stream, stream);
> +       KUNIT_EXPECT_FALSE(test, priv->stream_free_again);
>  }
>
>  /*
> @@ -279,8 +370,30 @@ 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 void string_stream_test_exit(struct kunit *test)
> +{
> +       struct string_stream_test_priv *priv = test->priv;
> +
> +       if (priv && priv->raw_stream)
> +               raw_free_string_stream(priv->raw_stream);
> +}
> +
>  static struct kunit_case string_stream_test_cases[] = {
>         KUNIT_CASE(string_stream_init_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),
> @@ -292,6 +405,8 @@ 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,
> +       .exit = string_stream_test_exit,
>  };
>  kunit_test_suites(&string_stream_test_suite);
> diff --git a/lib/kunit/string-stream.c b/lib/kunit/string-stream.c
> index 06104a729b45..1b55ac1be2e5 100644
> --- a/lib/kunit/string-stream.c
> +++ b/lib/kunit/string-stream.c
> @@ -6,6 +6,7 @@
>   * Author: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
>   */
>
> +#include <kunit/static_stub.h>
>  #include <kunit/test.h>
>  #include <linux/list.h>
>  #include <linux/slab.h>
> @@ -167,6 +168,8 @@ bool string_stream_is_empty(struct string_stream *stream)
>
>  void raw_free_string_stream(struct string_stream *stream)
>  {
> +       KUNIT_STATIC_STUB_REDIRECT(raw_free_string_stream, stream);
> +
>         string_stream_clear(stream);
>         kfree(stream);
>  }
> --
> 2.30.2
>

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