Messages in this thread | | | From | Brendan Higgins <> | Date | Wed, 5 Oct 2022 16:39:14 -0400 | Subject | Re: [PATCH v2 4/5] kunit: make kunit_kfree() not segfault on invalid inputs |
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On Fri, Jul 22, 2022 at 1:15 PM Daniel Latypov <dlatypov@google.com> wrote: > > 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> > Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
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