From e562e309d1d4ac05457c1454b6007071f13b5684 Mon Sep 17 00:00:00 2001 From: Daniel Latypov Date: Fri, 22 Jul 2022 17:15:33 +0000 Subject: kunit: make kunit_kfree() not segfault on invalid inputs 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 --- 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 0f9c1fb32da7..0e9ff5d8fe84 100644 --- a/lib/kunit/test.c +++ b/lib/kunit/test.c @@ -722,18 +722,8 @@ 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); -- cgit v1.2.3