Re: Odd-sized kmem_cache_alloc and slub_debug=Z

[Marco Elver]

On Fri, 7 Aug 2020 at 21:06, Pekka Enberg <penberg@xxxxxxxxx> wrote:
...
> Yeah, it reproduces with defconfig too, as long as you remember to
> pass "slub_debug=Z"... :-/
>
> The following seems to be the culprit:
>
> commit 3202fa62fb43087387c65bfa9c100feffac74aa6
> Author: Kees Cook <keescook@xxxxxxxxxxxx>
> Date:   Wed Apr 1 21:04:27 2020 -0700
>
>     slub: relocate freelist pointer to middle of object
>
> Reverting this commit and one of it's follow up fixes from Kees from
> v5.8 makes the issue go away for me. Btw, please note that caches with
> size 24 and larger do not trigger this bug, so the issue is that with
> small enough object size, we're stomping on allocator metadata (I
> assume part of the freelist).

Was there a patch to fix this? Checking, just in case I missed it.

Thanks,
-- Marco