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 dlatypov@google.com --- lib/kunit/test.c | 14 ++------------ 1 file changed, 2 insertions(+), 12 deletions(-)
diff --git a/lib/kunit/test.c b/lib/kunit/test.c index 82019a78462e..c7ca87484968 100644 --- a/lib/kunit/test.c +++ b/lib/kunit/test.c @@ -698,18 +698,8 @@ static inline bool kunit_kfree_match(struct kunit *test,
void kunit_kfree(struct kunit *test, const void *ptr) { - struct kunit_resource *res; - - res = kunit_find_resource(test, kunit_kfree_match, (void *)ptr); - - /* - * Removing the resource from the list of resources drops the - * reference count to 1; the final put will trigger the free. - */ - kunit_remove_resource(test, res); - - kunit_put_resource(res); - + if (kunit_destroy_resource(test, kunit_kfree_match, (void *)ptr)) + KUNIT_FAIL(test, "kunit_kfree: %px already freed or not allocated by kunit", ptr); } EXPORT_SYMBOL_GPL(kunit_kfree);