On 2014/2/28 10:08, 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: > > [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: > [<ffffffff814275f4>] dev_mc_sync+0x64/0xb0 > [32524.386326] > [32524.386326] but task is already holding lock: > [32524.386330] (&vlan_netdev_addr_lock_key/1){+.....}, at: > [<ffffffff8141af83>] 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: [<ffffffff81431d42>] > rtnl_lock+0x12/0x20 > [32524.386387] #1: (&vlan_netdev_addr_lock_key/1){+.....}, at: > [<ffffffff8141af83>] 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] [<ffffffff814f68a2>] dump_stack+0x6a/0x78 > [32524.386448] [<ffffffff810a35fb>] __lock_acquire+0x7ab/0x1940 > [32524.386454] [<ffffffff810a323a>] ? __lock_acquire+0x3ea/0x1940 > [32524.386459] [<ffffffff810a4874>] lock_acquire+0xe4/0x110 > [32524.386464] [<ffffffff814275f4>] ? dev_mc_sync+0x64/0xb0 > [32524.386471] [<ffffffff814fc07a>] _raw_spin_lock_nested+0x2a/0x40 > [32524.386476] [<ffffffff814275f4>] ? dev_mc_sync+0x64/0xb0 > [32524.386481] [<ffffffff814275f4>] dev_mc_sync+0x64/0xb0 > [32524.386489] [<ffffffffa0500cab>] vlan_dev_set_rx_mode+0x2b/0x50 [8021q] > [32524.386495] [<ffffffff8141addf>] __dev_set_rx_mode+0x5f/0xb0 > [32524.386500] [<ffffffff8141af8b>] dev_set_rx_mode+0x2b/0x40 > [32524.386506] [<ffffffff8141b3cf>] __dev_open+0xef/0x150 > [32524.386511] [<ffffffff8141b177>] __dev_change_flags+0xa7/0x190 > [32524.386516] [<ffffffff8141b292>] dev_change_flags+0x32/0x80 > [32524.386524] [<ffffffff8149ca56>] devinet_ioctl+0x7d6/0x830 > [32524.386532] [<ffffffff81437b0b>] ? dev_ioctl+0x34b/0x660 > [32524.386540] [<ffffffff814a05b0>] inet_ioctl+0x80/0xa0 > [32524.386550] [<ffffffff8140199d>] sock_do_ioctl+0x2d/0x60 > [32524.386558] [<ffffffff81401a52>] sock_ioctl+0x82/0x2a0 > [32524.386568] [<ffffffff811a7123>] do_vfs_ioctl+0x93/0x590 > [32524.386578] [<ffffffff811b2705>] ? rcu_read_lock_held+0x45/0x50 > [32524.386586] [<ffffffff811b39e5>] ? __fget_light+0x105/0x110 > [32524.386594] [<ffffffff811a76b1>] SyS_ioctl+0x91/0xb0 > [32524.386604] [<ffffffff815057e2>] 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 <dingtianh...@huawei.com> > --- > 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; > + } > +
Self Naked, whitespace errors detected, sorry for that, resend soon. Ding > if (vlan_find_dev(real_dev, protocol, vlan_id) != NULL) > return -EEXIST; > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/