Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752070AbaB1Cnh (ORCPT ); Thu, 27 Feb 2014 21:43:37 -0500 Received: from szxga03-in.huawei.com ([119.145.14.66]:45048 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750941AbaB1Cng (ORCPT ); Thu, 27 Feb 2014 21:43:36 -0500 Message-ID: <530FF7BF.4030706@huawei.com> Date: Fri, 28 Feb 2014 10:43:11 +0800 From: Ding Tianhong User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:24.0) Gecko/20100101 Thunderbird/24.0.1 MIME-Version: 1.0 To: Patrick McHardy , "David S. Miller" , Netdev , "linux-kernel@vger.kernel.org" Subject: [PATCH net RESEND] vlan: don't allow to add VLAN on VLAN device Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.22.246] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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: [32524.386288] ============================================= [32524.386293] [ INFO: possible recursive locking detected ] [32524.386298] 3.14.0-rc2-0.7-default+ #35 Tainted: G O [32524.386302] --------------------------------------------- [32524.386306] ifconfig/3103 is trying to acquire lock: [32524.386310] (&vlan_netdev_addr_lock_key/1){+.....}, at: [] dev_mc_sync+0x64/0xb0 [32524.386326] [32524.386326] but task is already holding lock: [32524.386330] (&vlan_netdev_addr_lock_key/1){+.....}, at: [] dev_set_rx_mode+0x23/0x40 [32524.386341] [32524.386341] other info that might help us debug this: [32524.386345] Possible unsafe locking scenario: [32524.386345] [32524.386350] CPU0 [32524.386352] ---- [32524.386354] lock(&vlan_netdev_addr_lock_key/1); [32524.386359] lock(&vlan_netdev_addr_lock_key/1); [32524.386364] [32524.386364] *** DEADLOCK *** [32524.386364] [32524.386368] May be due to missing lock nesting notation [32524.386368] [32524.386373] 2 locks held by ifconfig/3103: [32524.386376] #0: (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x12/0x20 [32524.386387] #1: (&vlan_netdev_addr_lock_key/1){+.....}, at: [] dev_set_rx_mode+0x23/0x40 [32524.386398] [32524.386398] stack backtrace: [32524.386403] CPU: 1 PID: 3103 Comm: ifconfig Tainted: G O 3.14.0-rc2-0.7-default+ #35 [32524.386409] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007 [32524.386414] ffffffff81ffae40 ffff8800d9625ae8 ffffffff814f68a2 ffff8800d9625bc8 [32524.386421] ffffffff810a35fb ffff8800d8a8d9d0 00000000d9625b28 ffff8800d8a8e5d0 [32524.386428] 000003cc00000000 0000000000000002 ffff8800d8a8e5f8 0000000000000000 [32524.386435] Call Trace: [32524.386441] [] dump_stack+0x6a/0x78 [32524.386448] [] __lock_acquire+0x7ab/0x1940 [32524.386454] [] ? __lock_acquire+0x3ea/0x1940 [32524.386459] [] lock_acquire+0xe4/0x110 [32524.386464] [] ? dev_mc_sync+0x64/0xb0 [32524.386471] [] _raw_spin_lock_nested+0x2a/0x40 [32524.386476] [] ? dev_mc_sync+0x64/0xb0 [32524.386481] [] dev_mc_sync+0x64/0xb0 [32524.386489] [] vlan_dev_set_rx_mode+0x2b/0x50 [8021q] [32524.386495] [] __dev_set_rx_mode+0x5f/0xb0 [32524.386500] [] dev_set_rx_mode+0x2b/0x40 [32524.386506] [] __dev_open+0xef/0x150 [32524.386511] [] __dev_change_flags+0xa7/0x190 [32524.386516] [] dev_change_flags+0x32/0x80 [32524.386524] [] devinet_ioctl+0x7d6/0x830 [32524.386532] [] ? dev_ioctl+0x34b/0x660 [32524.386540] [] inet_ioctl+0x80/0xa0 [32524.386550] [] sock_do_ioctl+0x2d/0x60 [32524.386558] [] sock_ioctl+0x82/0x2a0 [32524.386568] [] do_vfs_ioctl+0x93/0x590 [32524.386578] [] ? rcu_read_lock_held+0x45/0x50 [32524.386586] [] ? __fget_light+0x105/0x110 [32524.386594] [] SyS_ioctl+0x91/0xb0 [32524.386604] [] system_call_fastpath+0x16/0x1b ======================================================================== 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 --- net/8021q/vlan.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c index 16fb0f4..052d201 100644 --- a/net/8021q/vlan.c +++ b/net/8021q/vlan.c @@ -132,6 +132,11 @@ int vlan_check_real_dev(struct net_device *real_dev, return -EOPNOTSUPP; } + if (real_dev->priv_flags & IFF_802_1Q_VLAN) { + pr_info("Don't add VLAN on VLAN device %s\n", name); + return -EOPNOTSUPP; + } + if (vlan_find_dev(real_dev, protocol, vlan_id) != NULL) return -EEXIST; -- 1.8.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/