[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Message-ID: <900f28da-83db-4b17-b56b-21acde70e47f@huawei.com>
Date: Thu, 26 Jun 2025 11:41:45 +0800
From: "dongchenchen (A)" <dongchenchen2@...wei.com>
To: Jakub Kicinski <kuba@...nel.org>
CC: <davem@...emloft.net>, <edumazet@...gle.com>, <pabeni@...hat.com>,
<horms@...nel.org>, <jiri@...nulli.us>, <oscmaes92@...il.com>,
<linux@...blig.org>, <pedro.netdev@...devamos.com>, <netdev@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <yuehaibing@...wei.com>,
<zhangchangzhong@...wei.com>
Subject: Re: [PATCH net] net: vlan: fix VLAN 0 refcount imbalance of toggling
filtering during runtime
> On Mon, 23 Jun 2025 19:30:08 +0800 Dong Chenchen wrote:
>> $ ip link add bond0 type bond mode 0
>> $ ip link add link bond0 name vlan0 type vlan id 0 protocol 802.1q
>> $ ethtool -K bond0 rx-vlan-filter off
>> $ ifconfig bond0 up
>> $ ethtool -K bond0 rx-vlan-filter on
>> $ ifconfig bond0 down
>> $ ifconfig bond0 up
>> $ ip link del vlan0
Hi, Jakub
Thanks for your review!
> Please try to figure out the reasonable combinations in which we can
> change the flags and bring the device up and down. Create a selftest
> in bash and add it under tools/testing/selftests/net
selftest patch will be added in v2.
>> diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c
>> index 06908e37c3d9..6e01ece0a95c 100644
>> --- a/net/8021q/vlan.c
>> +++ b/net/8021q/vlan.c
>> @@ -504,12 +504,21 @@ static int vlan_device_event(struct notifier_block *unused, unsigned long event,
>> break;
>>
>> case NETDEV_CVLAN_FILTER_PUSH_INFO:
>> + flgs = dev_get_flags(dev);
> Why call dev_get_flags()? You can test dev->flags & IFF_UP directly
Yes, there is no need to use this function, I will modify it in v2
>> + if (flgs & IFF_UP) {
>> + pr_info("adding VLAN 0 to HW filter on device %s\n",
>> + dev->name);
>> + vlan_vid_add(dev, htons(ETH_P_8021Q), 0);
> Not sure if this works always, because if we have no vlan at all when
> the device comes up vlan_info will be NULL and we won't even get here.
>
> IIUC adding vlan 0 has to be handled early, where UP is handled.
Yes, that's right.
the sequence as below can still trigger the issue:
$ ip link add bond0 type bond mode 0
$ ethtool -K bond0 rx-vlan-filter off
$ ifconfig bond0 up
$ ethtool -K bond0 rx-vlan-filter on
$ ip link add link bond0 name vlan0 type vlan id 0 protocol 802.1q
$ ifconfig bond0 down
$ ifconfig bond0 up
$ ip link del vlan0
maybe we can fix it by:
diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c
index 6e01ece0a95c..262f8d3f06ef 100644
--- a/net/8021q/vlan.c
+++ b/net/8021q/vlan.c
@@ -378,14 +378,18 @@ static int vlan_device_event(struct notifier_block *unused, unsigned long event,
return notifier_from_errno(err);
}
- if ((event == NETDEV_UP) &&
- (dev->features & NETIF_F_HW_VLAN_CTAG_FILTER)) {
+ if (((event == NETDEV_UP) &&
+ (dev->features & NETIF_F_HW_VLAN_CTAG_FILTER)) ||
+ (event == NETDEV_CVLAN_FILTER_PUSH_INFO &&
+ (dev->flags & IFF_UP))) {
pr_info("adding VLAN 0 to HW filter on device %s\n",
dev->name);
vlan_vid_add(dev, htons(ETH_P_8021Q), 0);
}
- if (event == NETDEV_DOWN &&
- (dev->features & NETIF_F_HW_VLAN_CTAG_FILTER))
+ if ((event == NETDEV_DOWN &&
+ (dev->features & NETIF_F_HW_VLAN_CTAG_FILTER)) ||
+ (event == NETDEV_CVLAN_FILTER_DROP_INFO &&
+ (dev->flags & IFF_UP)))
vlan_vid_del(dev, htons(ETH_P_8021Q), 0);
vlan_info = rtnl_dereference(dev->vlan_info);
------
Best regards
Dong Chenchen
>> + }
>> err = vlan_filter_push_vids(vlan_info, htons(ETH_P_8021Q));
>> if (err)
>> return notifier_from_errno(err);
>> break;
>>
>> case NETDEV_CVLAN_FILTER_DROP_INFO:
>> + flgs = dev_get_flags(dev);
>> + if (flgs & IFF_UP)
>> + vlan_vid_del(dev, htons(ETH_P_8021Q), 0);
>> vlan_filter_drop_vids(vlan_info, htons(ETH_P_8021Q));
Powered by blists - more mailing lists