On 2014/2/28 13:41, Florian Fainelli wrote:

2014-02-27 21:26 GMT-08:00 Ding Tianhong [off-list ref]:

quoted

On 2014/2/28 11:45, John Fastabend wrote:

quoted

On 2/27/2014 6:43 PM, Ding Tianhong wrote:

quoted

I run these steps:

modprobe 8021q
vconfig add eth2 20
vconfig add eth2.20 20
ifconfig eth2 xx.xx.xx.xx

then the Call Trace happened:

[...]

quoted

========================================================================

The reason is that if add vlan on vlan dev, the vlan dev will create vlan_info,
then the notification will let the real dev to run dev_set_rx_mode() and hold
netif_addr_lock, and then the real dev will call ndo_set_rx_mode(), if the real
dev is vlan dev, the ndo_set_rx_mode() will hold netif_addr_lock again, so deadlock
happened.

Don't allow to add vlan on vlan dev to fix this problem.

Signed-off-by: Ding Tianhong <redacted>
---

I'm not sure we can just disable stacked vlans. There might be something
using them today and they have worked in the past. Lets try to find a
better fix.

.John

Yes, maybe I miss something, can you gave me a scene that the use of eth2.20.30?
the device is created from vlan device eth2.20, than I will find a better way to fix it.

Is not QinQ (802.1ad) such as case [1]?

[1]: http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=8ad227ff89a7e6f05d07cd0acfd95ed3a24450ca
--
Florian

Yep, thanks a lot.

Ding