From: Ding Tianhong Subject: Re: [PATCH net RESEND] vlan: don't allow to add VLAN on VLAN device Date: Fri, 28 Feb 2014 14:34:16 +0800 Message-ID: <53102DE8.9090707@huawei.com> References: <530FF7BF.4030706@huawei.com> <53100677.2060705@intel.com> <53101E1A.6020707@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: John Fastabend , Patrick McHardy , "David S. Miller" , Netdev , "linux-kernel@vger.kernel.org" To: Florian Fainelli Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 2014/2/28 13:41, Florian Fainelli wrote: > 2014-02-27 21:26 GMT-08:00 Ding Tianhong : >> On 2014/2/28 11:45, John Fastabend wrote: >>> On 2/27/2014 6:43 PM, Ding Tianhong wrote: >>>> 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: >>>> >>> >>> [...] >>> >>>> ======================================================================== >>>> >>>> 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 >>>> --- >>> >>> 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