linux-dev/lib/kunit, branch master

kunit: update NULL vs IS_ERR() tests

2022-10-18T21:08:42Z

The alloc_string_stream() functions were changed from returning NULL on error to returning error pointers so these caller needs to be updated as well. Fixes: 78b1c6584fce ("kunit: string-stream: Simplify resource use") Signed-off-by: Dan Carpenter Reviewed-by: Daniel Latypov Reviewed-by: David Gow Signed-off-by: Shuah Khan

kunit: remove format func from struct kunit_assert, get it to 0 bytes

2022-10-07T16:16:38Z

Each calll to a KUNIT_EXPECT_*() macro creates a local variable which contains a struct kunit_assert. Normally, we'd hope the compiler would be able to optimize this away, but we've seen cases where it hasn't, see https://groups.google.com/g/kunit-dev/c/i3fZXgvBrfA/m/GbrMNej2BAAJ. In changes like commit 21957f90b28f ("kunit: split out part of kunit_assert into a static const"), we've moved more and more parts out of struct kunit_assert and its children types (kunit_binary_assert). This patch removes the final field and gets us to: sizeof(struct kunit_assert) == 0 sizeof(struct kunit_binary_assert) == 24 (on UML x86_64). This also reduces the amount of macro plumbing going on at the cost of passing in one more arg to the base KUNIT_ASSERTION macro and kunit_do_failed_assertion(). Signed-off-by: Daniel Latypov Reviewed-by: David Gow Signed-off-by: Shuah Khan

kunit: make kunit_kfree(NULL) a no-op to match kfree()

2022-10-07T16:15:56Z

The real kfree() function will silently return when given a NULL. So a user might reasonably think they can write the following code: char *buffer = NULL; if (param->use_buffer) buffer = kunit_kzalloc(test, 10, GFP_KERNEL); ... kunit_kfree(test, buffer); As-is, kunit_kfree() will mark the test as FAILED when buffer is NULL. (And in earlier times, it would segfault). Let's match the semantics of kfree(). Suggested-by: David Gow Signed-off-by: Daniel Latypov Reviewed-by: David Gow Reviewed-by: Brendan Higgins Signed-off-by: Shuah Khan

kunit: make kunit_kfree() not segfault on invalid inputs

2022-10-07T16:15:50Z

kunit_kfree() can only work on data ("resources") allocated by KUnit. Currently for code like this, > void *ptr = kmalloc(4, GFP_KERNEL); > kunit_kfree(test, ptr); kunit_kfree() will segfault. It'll try and look up the kunit_resource associated with `ptr` and get a NULL back, but it won't check for this. This means we also segfault if you double-free. Change kunit_kfree() so it'll notice these invalid pointers and respond by failing the test. Implementation: kunit_destroy_resource() does what kunit_kfree() does, but is more generic and returns -ENOENT when it can't find the resource. Sadly, unlike just letting it crash, this means we don't get a stack trace. But kunit_kfree() is so infrequently used it shouldn't be hard to track down the bad callsite anyways. After this change, the above code gives: > # example_simple_test: EXPECTATION FAILED at lib/kunit/test.c:702 > kunit_kfree: 00000000626ec200 already freed or not allocated by kunit Signed-off-by: Daniel Latypov Reviewed-by: David Gow Reviewed-by: Brendan Higgins Signed-off-by: Shuah Khan

kunit: make kunit_kfree() only work on pointers from kunit_malloc() and friends

2022-10-07T16:15:44Z

kunit_kfree() exists to clean up allocations from kunit_kmalloc() and friends early instead of waiting for this to happen automatically at the end of the test. But it can be used on *anything* registered with the kunit resource API. E.g. the last 2 statements are equivalent: struct kunit_resource *res = something(); kfree(res->data); kunit_put_resource(res); The problem is that there could be multiple resources that point to the same `data`. E.g. you can have a named resource acting as a pseudo-global variable in a test. If you point it to data allocated with kunit_kmalloc(), then calling `kunit_kfree(ptr)` has the chance to delete either the named resource or to kfree `ptr`. Which one it does depends on the order the resources are registered as kunit_kfree() will delete resources in LIFO order. So this patch restricts kunit_kfree() to only working on resources created by kunit_kmalloc(). Calling it is therefore guaranteed to free the memory, not do anything else. Note: kunit_resource_instance_match() wasn't used outside of KUnit, so it should be safe to remove from the public interface. It's also generally dangerous, as shown above, and shouldn't be used. Signed-off-by: Daniel Latypov Reviewed-by: David Gow Reviewed-by: Brendan Higgins Signed-off-by: Shuah Khan

kunit: drop test pointer in string_stream_fragment

2022-10-07T16:15:33Z

We already store the `struct kunit *test` in the string_stream object itself, so we need don't need to store a copy of this pointer in every fragment in the stream. Drop it, getting string_stream_fragment down the bare minimum: a list_head and the `char *` with the actual fragment. Signed-off-by: Daniel Latypov Reviewed-by: David Gow Reviewed-by: Brendan Higgins Signed-off-by: Shuah Khan

kunit: string-stream: Simplify resource use

2022-10-07T16:15:22Z

Currently, KUnit's string streams are themselves "KUnit resources". This is redundant since the stream itself is already allocated with kunit_kzalloc() and will thus be freed automatically at the end of the test. string-stream is only used internally within KUnit, and isn't using the extra features that resources provide like reference counting, being able to locate them dynamically as "test-local variables", etc. Indeed, the resource's refcount is never incremented when the pointer is returned. The fact that it's always manually destroyed is more evidence that the reference counting is unused. Signed-off-by: David Gow Signed-off-by: Daniel Latypov Reviewed-by: Brendan Higgins Signed-off-by: Shuah Khan

kunit: add kunit.enable to enable/disable KUnit test

2022-09-30T19:17:39Z

This patch adds the kunit.enable module parameter that will need to be set to true in addition to KUNIT being enabled for KUnit tests to run. The default value is true giving backwards compatibility. However, for the production+testing use case the new config option KUNIT_DEFAULT_ENABLED can be set to N requiring the tester to opt-in by passing kunit.enable=1 to the kernel. Signed-off-by: Joe Fradley Reviewed-by: David Gow Signed-off-by: Shuah Khan

kunit: executor: Fix a memory leak on failure in kunit_filter_tests

2022-07-14T16:35:56Z

It's possible that memory allocation for 'filtered' will fail, but for the copy of the suite to succeed. In this case, the copy could be leaked. Properly free 'copy' in the error case for the allocation of 'filtered' failing. Note that there may also have been a similar issue in kunit_filter_subsuites, before it was removed in "kunit: flatten kunit_suite*** to kunit_suite** in .kunit_test_suites". This was reported by clang-analyzer via the kernel test robot, here: https://lore.kernel.org/all/c8073b8e-7b9e-0830-4177-87c12f16349c@intel.com/ And by smatch via Dan Carpenter and the kernel test robot: https://lore.kernel.org/all/202207101328.ASjx88yj-lkp@intel.com/ Fixes: a02353f49162 ("kunit: bail out of test filtering logic quicker if OOM") Reported-by: kernel test robot Reported-by: kernel test robot Reported-by: Dan Carpenter Reviewed-by: Daniel Latypov Reviewed-by: Brendan Higgins Signed-off-by: David Gow Signed-off-by: Shuah Khan

kunit: flatten kunit_suite* to kunit_suite in .kunit_test_suites

2022-07-11T23:13:15Z

We currently store kunit suites in the .kunit_test_suites ELF section as a `struct kunit_suite***` (modulo some `const`s). For every test file, we store a struct kunit_suite** NULL-terminated array. This adds quite a bit of complexity to the test filtering code in the executor. Instead, let's just make the .kunit_test_suites section contain a single giant array of struct kunit_suite pointers, which can then be directly manipulated. This array is not NULL-terminated, and so none of the test filtering code needs to NULL-terminate anything. Tested-by: Maíra Canal Reviewed-by: Brendan Higgins Signed-off-by: Daniel Latypov Co-developed-by: David Gow Signed-off-by: David Gow Signed-off-by: Shuah Khan