On Wed, Jun 19, 2024 at 6:10 PM Xin Long <[email protected]> wrote:
>
> On Wed, Jun 19, 2024 at 5:20 PM Florian Westphal <[email protected]> wrote:
> >
> > Xin Long <[email protected]> wrote:
> > > Got it, I will fix this in ovs.
> >
> > Thanks!
> >
> > I don't want to throw more work at you, but since you are
> > already working on ovs+conntrack:
> >
> > ovs_ct_init() is bad, as this runs unconditionally.
> >
> > modprobe openvswitch -> conntrack becomes active in all
> > existing and future namespaces.
> >
> > Conntrack is slow, we should avoid this behaviour.
> >
> > ovs_ct_limit_init() should be called only when the feature is
> > configured (the problematic call is nf_conncount_init, as that
> > turns on connection tracking, the kmalloc etc is fine).
> understand.
>
> >
> > Likewise, nf_connlabels_get() should only be called when
> > labels are added/configured, not at the start.
> >
> > I resolved this for tc in 70f06c115bcc but it seems i never
> > got around to fix it for ovs.
Hi, Florian,
I noticed the warning in nf_ct_ext_add() while I'm making this change:
WARN_ON(nf_ct_is_confirmed(ct));
It can be triggered by these ovs flows from ovs selftests:
table=0,priority=30,in_port=1,ip,nw_dst=172.1.1.2,actions=ct(commit,nat(dst=10.1.1.2:80),table=1)
table=1,ip,actions=ct(commit,nat(src=10.1.1.240),exec(set_field:0xac->ct_mark,set_field:0xac->ct_label),table=2)
The 1st flow creates the ct and commits/confirms it, then the 2nd flow is
setting ct_label on a confirmed ct. With this change, the connlabels ext
is not yet allocated at the time, and then the warning is triggered when
allocating it in nf_ct_ext_add().
tc act_ct action doesn't have this issue, as it returns an error if the
connlabels is not found in tcf_ct_act_set_labels(), instead of allocating it.
I can avoid this warning by not allocating ext for commit ct in ovs:
@@ -426,7 +426,7 @@ static int ovs_ct_set_labels(struct nf_conn *ct,
struct sw_flow_key *key,
struct nf_conn_labels *cl;
int err;
- cl = ovs_ct_get_conn_labels(ct);
+ cl = nf_ct_labels_find(ct);
if (!cl)
return -ENOSPC;
However, the test case would fail, although the failure can be worked around
by setting ct_label in the 1st rule:
table=0,priority=30,in_port=1,ip,nw_dst=172.1.1.2,actions=ct(commit,nat(dst=10.1.1.2:80),exec(set_field:0x01->ct_label),table=1)
So I'm worrying our change may break some existing OVS user cases.
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