Commit 047a8a0a authored by Daniel Latypov's avatar Daniel Latypov Committed by Shuah Khan
Browse files

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



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: default avatarDaniel Latypov <dlatypov@google.com>
Reviewed-by: default avatarDavid Gow <davidgow@google.com>
Reviewed-by: default avatarBrendan Higgins <brendanhiggins@google.com>
Signed-off-by: default avatarShuah Khan <skhan@linuxfoundation.org>
parent 4db4598b

include/kunit/resource.h

+0 −16
Original line number Diff line number Diff line
@@ -300,22 +300,6 @@ typedef bool (*kunit_resource_match_t)(struct kunit *test, 
				       struct kunit_resource *res,

				       void *match_data);



/**

 * kunit_resource_instance_match() - Match a resource with the same instance.

 * @test: Test case to which the resource belongs.

 * @res: The resource.

 * @match_data: The resource pointer to match against.

 *

 * An instance of kunit_resource_match_t that matches a resource whose

 * allocation matches @match_data.

 */

static inline bool kunit_resource_instance_match(struct kunit *test,

						 struct kunit_resource *res,

						 void *match_data)

{

	return res->data == match_data;

}



/**

 * kunit_resource_name_match() - Match a resource with the same name.

 * @test: Test case to which the resource belongs.

lib/kunit/kunit-test.c

+7 −0
Original line number Diff line number Diff line
@@ -161,6 +161,13 @@ static void kunit_resource_test_alloc_resource(struct kunit *test) 
	kunit_put_resource(res);

}



static inline bool kunit_resource_instance_match(struct kunit *test,

						 struct kunit_resource *res,

						 void *match_data)

{

	return res->data == match_data;

}



/*

 * Note: tests below use kunit_alloc_and_get_resource(), so as a consequence

 * they have a reference to the associated resource that they must release

lib/kunit/test.c

+8 −2
Original line number Diff line number Diff line
@@ -713,12 +713,18 @@ void *kunit_kmalloc_array(struct kunit *test, size_t n, size_t size, gfp_t gfp) 
}

EXPORT_SYMBOL_GPL(kunit_kmalloc_array);



static inline bool kunit_kfree_match(struct kunit *test,

				     struct kunit_resource *res, void *match_data)

{

	/* Only match resources allocated with kunit_kmalloc() and friends. */

	return res->free == kunit_kmalloc_array_free && res->data == match_data;

}



void kunit_kfree(struct kunit *test, const void *ptr)

{

	struct kunit_resource *res;



	res = kunit_find_resource(test, kunit_resource_instance_match,

				  (void *)ptr);

	res = kunit_find_resource(test, kunit_kfree_match, (void *)ptr);



	/*

	 * Removing the resource from the list of resources drops the