Re: [PATCH] UML: add support for KASAN under x86_64

Dmitry Vyukov
2020-03-11T10:46:25Z

On Wed, Mar 11, 2020 at 11:32 AM Johannes Berg
<johannes@sipsolutions.net> wrote:
>
> Hi,
>
> > Hi all, I just want to bump this so we can get all the comments while
> > this is still fresh in everyone's minds. I would love if some UML
> > maintainers could give their thoughts!
>
> I'm not the maintainer, and I don't know where Richard is, but I just
> tried with the test_kasan.ko module, and that seems to work. Did you
> test that too? I was surprised to see this because you said you didn't
> test modules, but surely this would've been the easiest way?
>
> Anyway, as expected, stack (and of course alloca) OOB access is not
> detected right now, but otherwise it seems great.
>
> Here's the log:
> https://p.sipsolutions.net/ca9b4157776110fe.txt
>
> I'll repost my module init thing as a proper patch then, I guess.
>
>
> I do see issues with modules though, e.g.
> https://p.sipsolutions.net/1a2df5f65d885937.txt
>
> where we seem to get some real confusion when lockdep is storing the
> stack trace??
>
> And https://p.sipsolutions.net/9a97e8f68d8d24b7.txt, where something
> convinces ASAN that an address is a user address (it might even be
> right?) and it disallows kernel access to it?

Please pass these reports via scripts/decode_stacktrace.sh to add line
numbers (or any other symbolization script). What is the base
revision?
Hard to analyze without line numbers.

> Also, do you have any intention to work on the stack later? For me,
> enabling that doesn't even report any issues, it just hangs at 'boot'.
>
> johannes
>