On Wed, Sep 15, 2021 at 5:03 AM Daniel Latypov <dlatypov@xxxxxxxxxx> wrote:
>
> This test assumes that the declared kunit_suite object is the exact one
> which is being executed, which KUnit will not guarantee [1].
>
> Specifically, `suite->log` is not initialized until a suite object is
> executed. So if KUnit makes a copy of the suite and runs that instead,
> this test dereferences an invalid pointer and (hopefully) segfaults.
>
> N.B. since we no longer assume this, we can no longer verify that
> `suite->log` is *not* allocated during normal execution.
>
> An alternative to this patch that would allow us to test that would
> require exposing an API for the current test to get its current suite.
> Exposing that for one internal kunit test seems like overkill, and
> grants users more footguns (e.g. reusing a test case in multiple suites
> and changing behavior based on the suite name, dynamically modifying the
> setup/cleanup funcs, storing/reading stuff out of the suite->log, etc.).
>
> [1] In a subsequent patch, KUnit will allow running subsets of test
> cases within a suite by making a copy of the suite w/ the filtered test
> list. But there are other reasons KUnit might execute a copy, e.g. if it
> ever wants to support parallel execution of different suites, recovering
> from errors and restarting suites
>
> Signed-off-by: Daniel Latypov <dlatypov@xxxxxxxxxx>
> Reviewed-by: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
> ---
Thanks for fixing this.
I do think that using "fake" tests/suites like this in more cases will
unlock testing other parts of KUnit as well.
Reviewed-by: David Gow <davidgow@xxxxxxxxxx>
Cheers,
-- David
> lib/kunit/kunit-test.c | 14 ++++++++------
> 1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/lib/kunit/kunit-test.c b/lib/kunit/kunit-test.c
> index d69efcbed624..555601d17f79 100644
> --- a/lib/kunit/kunit-test.c
> +++ b/lib/kunit/kunit-test.c
> @@ -415,12 +415,15 @@ static struct kunit_suite kunit_log_test_suite = {
>
> static void kunit_log_test(struct kunit *test)
> {
> - struct kunit_suite *suite = &kunit_log_test_suite;
> + struct kunit_suite suite;
> +
> + suite.log = kunit_kzalloc(test, KUNIT_LOG_SIZE, GFP_KERNEL);
> + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, suite.log);
>
> kunit_log(KERN_INFO, test, "put this in log.");
> kunit_log(KERN_INFO, test, "this too.");
> - kunit_log(KERN_INFO, suite, "add to suite log.");
> - kunit_log(KERN_INFO, suite, "along with this.");
> + kunit_log(KERN_INFO, &suite, "add to suite log.");
> + kunit_log(KERN_INFO, &suite, "along with this.");
>
> #ifdef CONFIG_KUNIT_DEBUGFS
> KUNIT_EXPECT_NOT_ERR_OR_NULL(test,
> @@ -428,12 +431,11 @@ static void kunit_log_test(struct kunit *test)
> KUNIT_EXPECT_NOT_ERR_OR_NULL(test,
> strstr(test->log, "this too."));
> KUNIT_EXPECT_NOT_ERR_OR_NULL(test,
> - strstr(suite->log, "add to suite log."));
> + strstr(suite.log, "add to suite log."));
> KUNIT_EXPECT_NOT_ERR_OR_NULL(test,
> - strstr(suite->log, "along with this."));
> + strstr(suite.log, "along with this."));
> #else
> KUNIT_EXPECT_PTR_EQ(test, test->log, (char *)NULL);
> - KUNIT_EXPECT_PTR_EQ(test, suite->log, (char *)NULL);
> #endif
> }
>
>
> base-commit: 316346243be6df12799c0b64b788e06bad97c30b
> --
> 2.33.0.309.g3052b89438-goog
>
