linux-stable.git/lib/kunit/test.c, branch v6.2.2

kunit: Export kunit_running()

2023-01-20T17:03:04+00:00

Using kunit_fail_current_test() in a loadable module causes a link
error like:

ERROR: modpost: "kunit_running" [drivers/gpu/drm/vc4/vc4.ko] undefined!

Export the symbol to allow using it from modules.

Fixes: da43ff045c3f ("drm/vc4: tests: Fail the current test if we access a register")
Signed-off-by: Arnd Bergmann 
Reviewed-by: David Gow 
Signed-off-by: Shuah Khan

Merge tag 'linux-kselftest-kunit-next-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

2022-12-13T00:42:57+00:00

Pull KUnit updates from Shuah Khan:
 "Several enhancements, fixes, clean-ups, documentation updates,
  improvements to logging and KTAP compliance of KUnit test output:

   - log numbers in decimal and hex

   - parse KTAP compliant test output

   - allow conditionally exposing static symbols to tests when KUNIT is
     enabled

   - make static symbols visible during kunit testing

   - clean-ups to remove unused structure definition"

* tag 'linux-kselftest-kunit-next-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (29 commits)
  Documentation: dev-tools: Clarify requirements for result description
  apparmor: test: make static symbols visible during kunit testing
  kunit: add macro to allow conditionally exposing static symbols to tests
  kunit: tool: make parser preserve whitespace when printing test log
  Documentation: kunit: Fix "How Do I Use This" / "Next Steps" sections
  kunit: tool: don't include KTAP headers and the like in the test log
  kunit: improve KTAP compliance of KUnit test output
  kunit: tool: parse KTAP compliant test output
  mm: slub: test: Use the kunit_get_current_test() function
  kunit: Use the static key when retrieving the current test
  kunit: Provide a static key to check if KUnit is actively running tests
  kunit: tool: make --json do nothing if --raw_ouput is set
  kunit: tool: tweak error message when no KTAP found
  kunit: remove KUNIT_INIT_MEM_ASSERTION macro
  Documentation: kunit: Remove redundant 'tips.rst' page
  Documentation: KUnit: reword description of assertions
  Documentation: KUnit: make usage.rst a superset of tips.rst, remove duplication
  kunit: eliminate KUNIT_INIT_*_ASSERT_STRUCT macros
  kunit: tool: remove redundant file.close() call in unit test
  kunit: tool: unit tests all check parser errors, standardize formatting a bit
  ...

kunit: improve KTAP compliance of KUnit test output

2022-12-12T21:13:47+00:00

Change KUnit test output to better comply with KTAP v1 specifications
found here: https://kernel.org/doc/html/latest/dev-tools/ktap.html.
1) Use "KTAP version 1" instead of "TAP version 14" as test output header
2) Remove '-' between test number and test name on test result lines
2) Add KTAP version lines to each subtest header as well

Note that the new KUnit output still includes the “# Subtest” line now
located after the KTAP version line. This does not completely match the
KTAP v1 spec but since it is classified as a diagnostic line, it is not
expected to be disruptive or break any existing parsers. This
“# Subtest” line comes from the TAP 14 spec
(https://testanything.org/tap-version-14-specification.html) and it is
used to define the test name before the results.

Original output:

 TAP version 14
 1..1
   # Subtest: kunit-test-suite
   1..3
   ok 1 - kunit_test_1
   ok 2 - kunit_test_2
   ok 3 - kunit_test_3
 # kunit-test-suite: pass:3 fail:0 skip:0 total:3
 # Totals: pass:3 fail:0 skip:0 total:3
 ok 1 - kunit-test-suite

New output:

 KTAP version 1
 1..1
   KTAP version 1
   # Subtest: kunit-test-suite
   1..3
   ok 1 kunit_test_1
   ok 2 kunit_test_2
   ok 3 kunit_test_3
 # kunit-test-suite: pass:3 fail:0 skip:0 total:3
 # Totals: pass:3 fail:0 skip:0 total:3
 ok 1 kunit-test-suite

Signed-off-by: Rae Moar 
Reviewed-by: Daniel Latypov 
Reviewed-by: David Gow 
Tested-by: Anders Roxell 
Signed-off-by: Shuah Khan

kunit: Provide a static key to check if KUnit is actively running tests

2022-12-12T21:13:47+00:00

KUnit does a few expensive things when enabled. This hasn't been a
problem because KUnit was only enabled on test kernels, but with a few
people enabling (but not _using_) KUnit on production systems, we need a
runtime way of handling this.

Provide a 'kunit_running' static key (defaulting to false), which allows
us to hide any KUnit code behind a static branch. This should reduce the
performance impact (on other code) of having KUnit enabled to a single
NOP when no tests are running.

Note that, while it looks unintuitive, tests always run entirely within
__kunit_test_suites_init(), so it's safe to decrement the static key at
the end of this function, rather than in __kunit_test_suites_exit(),
which is only there to clean up results in debugfs.

Signed-off-by: David Gow 
Reviewed-by: Daniel Latypov 
Signed-off-by: Shuah Khan

kunit: update NULL vs IS_ERR() tests

2022-10-18T21:08:42+00:00

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

2022-10-07T16:16:38+00:00

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()

2022-10-07T16:15:56+00:00

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

2022-10-07T16:15:50+00:00

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

2022-10-07T16:15:44+00:00

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: string-stream: Simplify resource use

2022-10-07T16:15:22+00:00

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