On Wed, Aug 1, 2018 at 3:46 PM, Florian Westphal [off-list ref] wrote:

Dmitry Vyukov [off-list ref] wrote:

quoted

If that scenario is possible that a fix would be to make

Looks possible.

quoted

__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.