netdev - Re: [ovs-dev] [PATCH net] Revert "openvswitch: switch to per-action label counting in conntrack"

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Message-ID: <fd11917d-ff8e-4de3-ba65-6e5da993db6a@nvidia.com>
Date: Thu, 13 Mar 2025 11:17:52 +0800
From: Jianbo Liu <jianbol@...dia.com>
To: Aaron Conole <aconole@...hat.com>, Xin Long <lucien.xin@...il.com>
CC: network dev <netdev@...r.kernel.org>, <dev@...nvswitch.org>,
	<ovs-dev@...nvswitch.org>, Marcelo Ricardo Leitner
	<marcelo.leitner@...il.com>, Florian Westphal <fw@...len.de>, Ilya Maximets
	<i.maximets@....org>, Eric Dumazet <edumazet@...gle.com>, <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>, <davem@...emloft.net>
Subject: Re: [ovs-dev] [PATCH net] Revert "openvswitch: switch to per-action
 label counting in conntrack"



On 3/12/2025 10:25 PM, Aaron Conole wrote:
> Xin Long <lucien.xin@...il.com> writes:
> 
>> Currently, ovs_ct_set_labels() is only called for confirmed conntrack
>> entries (ct) within ovs_ct_commit(). However, if the conntrack entry
>> does not have the labels_ext extension, attempting to allocate it in
>> ovs_ct_get_conn_labels() for a confirmed entry triggers a warning in
>> nf_ct_ext_add():
>>
>>    WARN_ON(nf_ct_is_confirmed(ct));
>>
>> This happens when the conntrack entry is created externally before OVS
>> increments net->ct.labels_used. The issue has become more likely since
>> commit fcb1aa5163b1 ("openvswitch: switch to per-action label counting
>> in conntrack"), which changed to use per-action label counting and
>> increment net->ct.labels_used when a flow with ct action is added.
>>
>> Since there’s no straightforward way to fully resolve this issue at the
>> moment, this reverts the commit to avoid breaking existing use cases.
>>
>> Fixes: fcb1aa5163b1 ("openvswitch: switch to per-action label counting in conntrack")
>> Reported-by: Jianbo Liu <jianbol@...dia.com>
>> Signed-off-by: Xin Long <lucien.xin@...il.com>
>> ---
> 
> I did a quick test using the case provided by Jianbo and I wasn't able
> to generate the warning.  If possible, I'd like Jianbo to confirm that
> it works as well.

Yes, it works. The warning is gone after applying this revert. Thanks!

> 
> Acked-by: Aaron Conole <aconole@...hat.com>
> 
>>   net/openvswitch/conntrack.c | 30 ++++++++++++++++++------------
>>   net/openvswitch/datapath.h  |  3 +++
>>   2 files changed, 21 insertions(+), 12 deletions(-)
>>
>> diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
>> index 3bb4810234aa..e573e9221302 100644
>> --- a/net/openvswitch/conntrack.c
>> +++ b/net/openvswitch/conntrack.c
>> @@ -1368,8 +1368,11 @@ bool ovs_ct_verify(struct net *net, enum ovs_key_attr attr)
>>   	    attr == OVS_KEY_ATTR_CT_MARK)
>>   		return true;
>>   	if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) &&
>> -	    attr == OVS_KEY_ATTR_CT_LABELS)
>> -		return true;
>> +	    attr == OVS_KEY_ATTR_CT_LABELS) {
>> +		struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
>> +
>> +		return ovs_net->xt_label;
>> +	}
>>   
>>   	return false;
>>   }
>> @@ -1378,7 +1381,6 @@ int ovs_ct_copy_action(struct net *net, const struct nlattr *attr,
>>   		       const struct sw_flow_key *key,
>>   		       struct sw_flow_actions **sfa,  bool log)
>>   {
>> -	unsigned int n_bits = sizeof(struct ovs_key_ct_labels) * BITS_PER_BYTE;
>>   	struct ovs_conntrack_info ct_info;
>>   	const char *helper = NULL;
>>   	u16 family;
>> @@ -1407,12 +1409,6 @@ int ovs_ct_copy_action(struct net *net, const struct nlattr *attr,
>>   		return -ENOMEM;
>>   	}
>>   
>> -	if (nf_connlabels_get(net, n_bits - 1)) {
>> -		nf_ct_tmpl_free(ct_info.ct);
>> -		OVS_NLERR(log, "Failed to set connlabel length");
>> -		return -EOPNOTSUPP;
>> -	}
>> -
>>   	if (ct_info.timeout[0]) {
>>   		if (nf_ct_set_timeout(net, ct_info.ct, family, key->ip.proto,
>>   				      ct_info.timeout))
>> @@ -1581,7 +1577,6 @@ static void __ovs_ct_free_action(struct ovs_conntrack_info *ct_info)
>>   	if (ct_info->ct) {
>>   		if (ct_info->timeout[0])
>>   			nf_ct_destroy_timeout(ct_info->ct);
>> -		nf_connlabels_put(nf_ct_net(ct_info->ct));
>>   		nf_ct_tmpl_free(ct_info->ct);
>>   	}
>>   }
>> @@ -2006,9 +2001,17 @@ struct genl_family dp_ct_limit_genl_family __ro_after_init = {
>>   
>>   int ovs_ct_init(struct net *net)
>>   {
>> -#if	IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
>> +	unsigned int n_bits = sizeof(struct ovs_key_ct_labels) * BITS_PER_BYTE;
>>   	struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
>>   
>> +	if (nf_connlabels_get(net, n_bits - 1)) {
>> +		ovs_net->xt_label = false;
>> +		OVS_NLERR(true, "Failed to set connlabel length");
>> +	} else {
>> +		ovs_net->xt_label = true;
>> +	}
>> +
>> +#if	IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
>>   	return ovs_ct_limit_init(net, ovs_net);
>>   #else
>>   	return 0;
>> @@ -2017,9 +2020,12 @@ int ovs_ct_init(struct net *net)
>>   
>>   void ovs_ct_exit(struct net *net)
>>   {
>> -#if	IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
>>   	struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
>>   
>> +#if	IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
>>   	ovs_ct_limit_exit(net, ovs_net);
>>   #endif
>> +
>> +	if (ovs_net->xt_label)
>> +		nf_connlabels_put(net);
>>   }
>> diff --git a/net/openvswitch/datapath.h b/net/openvswitch/datapath.h
>> index 365b9bb7f546..9ca6231ea647 100644
>> --- a/net/openvswitch/datapath.h
>> +++ b/net/openvswitch/datapath.h
>> @@ -160,6 +160,9 @@ struct ovs_net {
>>   #if	IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
>>   	struct ovs_ct_limit_info *ct_limit_info;
>>   #endif
>> +
>> +	/* Module reference for configuring conntrack. */
>> +	bool xt_label;
>>   };
>>   
>>   /**
>