linux.git/lib/kunit/kunit-test.c, branch v6.9-rc2

kunit: Fix a NULL vs IS_ERR() bug

2024-01-22T14:58:12+00:00

The kunit_device_register() function doesn't return NULL, it returns
error pointers.  Change the KUNIT_ASSERT_NOT_NULL() to check for
ERR_OR_NULL().

Fixes: d03c720e03bd ("kunit: Add APIs for managing devices")
Signed-off-by: Dan Carpenter 
Reviewed-by: Rae Moar 
Reviewed-by: David Gow 
Signed-off-by: Shuah Khan

kunit: Add APIs for managing devices

2023-12-18T20:28:08+00:00

Tests for drivers often require a struct device to pass to other
functions. While it's possible to create these with
root_device_register(), or to use something like a platform device, this
is both a misuse of those APIs, and can be difficult to clean up after,
for example, a failed assertion.

Add some KUnit-specific functions for registering and unregistering a
struct device:
- kunit_device_register()
- kunit_device_register_with_driver()
- kunit_device_unregister()

These helpers allocate a on a 'kunit' bus which will either probe the
driver passed in (kunit_device_register_with_driver), or will create a
stub driver (kunit_device_register) which is cleaned up on test shutdown.

Devices are automatically unregistered on test shutdown, but can be
manually unregistered earlier with kunit_device_unregister() in order
to, for example, test device release code.

Reviewed-by: Matti Vaittinen 
Reviewed-by: Maxime Ripard 
Signed-off-by: David Gow 
Reviewed-by: Greg Kroah-Hartman 
Signed-off-by: Shuah Khan

kunit: Add a macro to wrap a deferred action function

2023-12-18T20:21:14+00:00

KUnit's deferred action API accepts a void(*)(void *) function pointer
which is called when the test is exited. However, we very frequently
want to use existing functions which accept a single pointer, but which
may not be of type void*. While this is probably dodgy enough to be on
the wrong side of the C standard, it's been often used for similar
callbacks, and gcc's -Wcast-function-type seems to ignore cases where
the only difference is the type of the argument, assuming it's
compatible (i.e., they're both pointers to data).

However, clang 16 has introduced -Wcast-function-type-strict, which no
longer permits any deviation in function pointer type. This seems to be
because it'd break CFI, which validates the type of function calls.

This rather ruins our attempts to cast functions to defer them, and
leaves us with a few options. The one we've chosen is to implement a
macro which will generate a wrapper function which accepts a void*, and
casts the argument to the appropriate type.

For example, if you were trying to wrap:
void foo_close(struct foo *handle);
you could use:
KUNIT_DEFINE_ACTION_WRAPPER(kunit_action_foo_close,
			    foo_close,
			    struct foo *);

This would create a new kunit_action_foo_close() function, of type
kunit_action_t, which could be passed into kunit_add_action() and
similar functions.

In addition to defining this macro, update KUnit and its tests to use
it.

Link: https://github.com/ClangBuiltLinux/linux/issues/1750
Reviewed-by: Nathan Chancellor 
Tested-by: Nathan Chancellor 
Acked-by: Daniel Vetter 
Reviewed-by: Maxime Ripard 
Signed-off-by: David Gow 
Signed-off-by: Shuah Khan

kunit: test: Avoid cast warning when adding kfree() as an action

2023-11-14T20:01:57+00:00

In kunit_log_test() pass the kfree_wrapper() function to kunit_add_action()
instead of directly passing kfree().

This prevents a cast warning:

lib/kunit/kunit-test.c:565:25: warning: cast from 'void (*)(const void *)'
to 'kunit_action_t *' (aka 'void (*)(void *)') converts to incompatible
function type [-Wcast-function-type-strict]

   564		full_log = string_stream_get_string(test->log);
 > 565		kunit_add_action(test, (kunit_action_t *)kfree, full_log);

Signed-off-by: Richard Fitzgerald 
Reported-by: kernel test robot 
Closes: https://lore.kernel.org/oe-kbuild-all/202311070041.kWVYx7YP-lkp@intel.com/
Fixes: 05e2006ce493 ("kunit: Use string_stream for test log")
Reviewed-by: David Gow 
Signed-off-by: Shuah Khan

kunit: Use string_stream for test log

2023-09-18T16:45:53+00:00

Replace the fixed-size log buffer with a string_stream so that the
log can grow as lines are added.

The existing kunit log tests have been updated for using a
string_stream as the log. No new test have been added because there
are already tests for the underlying string_stream.

As the log tests now depend on string_stream functions they cannot
build when kunit-test is a module. They have been surrounded by
a #if to replace them with skipping version when the test is
build as a module. Though this isn't pretty, it avoids moving
code to another file while that code is also being changed.

Signed-off-by: Richard Fitzgerald 
Reviewed-by: David Gow 
Signed-off-by: Shuah Khan

kunit: Add kunit_add_action() to defer a call until test exit

2023-05-25T14:52:55+00:00

Many uses of the KUnit resource system are intended to simply defer
calling a function until the test exits (be it due to success or
failure). The existing kunit_alloc_resource() function is often used for
this, but was awkward to use (requiring passing NULL init functions, etc),
and returned a resource without incrementing its reference count, which
-- while okay for this use-case -- could cause problems in others.

Instead, introduce a simple kunit_add_action() API: a simple function
(returning nothing, accepting a single void* argument) can be scheduled
to be called when the test exits. Deferred actions are called in the
opposite order to that which they were registered.

This mimics the devres API, devm_add_action(), and also provides
kunit_remove_action(), to cancel a deferred action, and
kunit_release_action() to trigger one early.

This is implemented as a resource under the hood, so the ordering
between resource cleanup and deferred functions is maintained.

Reviewed-by: Benjamin Berg 
Reviewed-by: Maxime Ripard 
Tested-by: Maxime Ripard 
Signed-off-by: David Gow 
Signed-off-by: Shuah Khan

kunit: add tests for using current KUnit test field

2023-04-05T18:51:30+00:00

Create test suite called "kunit_current" to add test coverage for the use
of current->kunit_test, which returns the current KUnit test.

Add two test cases:
- kunit_current_test to test current->kunit_test and the method
  kunit_get_current_test(), which utilizes current->kunit_test.

- kunit_current_fail_test to test the method
  kunit_fail_current_test(), which utilizes current->kunit_test.

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

kunit: fix bug of extra newline characters in debugfs logs

2023-03-10T20:59:43+00:00

Fix bug of the extra newline characters in debugfs logs. When a
line is added to debugfs with a newline character at the end,
an extra line appears in the debugfs log.

This is due to a discrepancy between how the lines are printed and how they
are added to the logs. Remove this discrepancy by checking if a newline
character is present before adding a newline character. This should closely
match the printk behavior.

Add kunit_log_newline_test to provide test coverage for this issue.  (Also,
move kunit_log_test above suite definition to remove the unnecessary
declaration prior to the suite definition)

As an example, say we add these two lines to the log:

kunit_log(..., "KTAP version 1\n");
kunit_log(..., "1..1");

The debugfs log before this fix:

 KTAP version 1

 1..1

The debugfs log after this fix:

 KTAP version 1
 1..1

Signed-off-by: Rae Moar 
Reviewed-by: David Gow 
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: Make kunit_remove_resource() idempotent

2022-04-05T19:32:50+00:00

The kunit_remove_resource() function is used to unlink a resource from
the list of resources in the test, making it no longer show up in
kunit_find_resource().

However, this could lead to a race condition if two threads called
kunit_remove_resource() on the same resource at the same time: the
resource would be removed from the list twice (causing a crash at the
second list_del()), and the refcount for the resource would be
decremented twice (instead of once, for the reference held by the
resource list).

Fix both problems, the first by using list_del_init(), and the second by
checking if the resource has already been removed using list_empty(),
and only decrementing its refcount if it has not.

Also add a KUnit test for the kunit_remove_resource() function which
tests this behaviour.

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