Re: SLAB_TYPESAFE_BY_RCU without constructors (was Re: [PATCH v4 13/17] khwasan: add hooks implementation)

[Dmitry Vyukov]

On Wed, Aug 1, 2018 at 3:46 PM, Florian Westphal <fw@xxxxxxxxx> wrote:
> Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote:
>> If that scenario is possible that a fix would be to make
>
> Looks possible.
>
>> __nf_conntrack_find_get ever return NULL iff it got NULL from
>> ____nf_conntrack_find (not if any of the checks has failed).
>
> I don't see why we need to restart on nf_ct_is_dying(), but other
> than that this seems ok.

Because it can be a wrong entry dying. When we check dying, we don't
yet know if we are looking at the right entry or not. If we
successfully acquire a reference, then recheck nf_ct_key_equal and
_then_ check dying, then we don't need to restart on dying. But with
the current check order, we need to restart on dying too.