From 20ea60ca9952bd19d4b0d74719daba305aef5178 Mon Sep 17 00:00:00 2001 From: lucien Date: Sun, 23 Nov 2014 15:04:11 +0800 Subject: [PATCH] ip_tunnel: the lack of vti_link_ops' dellink() cause kernel panic Now the vti_link_ops do not point the .dellink, for fb tunnel device (ip_vti0), the net_device will be removed as the default .dellink is unregister_netdevice_queue,but the tunnel still in the tunnel list, then if we add a new vti tunnel, in ip_tunnel_find(): hlist_for_each_entry_rcu(t, head, hash_node) { if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr && link == t->parms.link && ==> type == t->dev->type && ip_tunnel_key_match(&t->parms, flags, key)) break; } the panic will happen, cause dev of ip_tunnel *t is null: [ 3835.072977] IP: [] ip_tunnel_find+0x9d/0xc0 [ip_tunnel] [ 3835.073008] PGD b2c21067 PUD b7277067 PMD 0 [ 3835.073008] Oops: 0000 [#1] SMP ..... [ 3835.073008] Stack: [ 3835.073008] ffff8800b72d77f0 ffffffffa0411924 ffff8800bb956000 ffff8800b72d78e0 [ 3835.073008] ffff8800b72d78a0 0000000000000000 ffffffffa040d100 ffff8800b72d7858 [ 3835.073008] ffffffffa040b2e3 0000000000000000 0000000000000000 0000000000000000 [ 3835.073008] Call Trace: [ 3835.073008] [] ip_tunnel_newlink+0x64/0x160 [ip_tunnel] [ 3835.073008] [] vti_newlink+0x43/0x70 [ip_vti] [ 3835.073008] [] rtnl_newlink+0x4fa/0x5f0 [ 3835.073008] [] ? nla_strlcpy+0x5b/0x70 [ 3835.073008] [] ? rtnl_link_ops_get+0x40/0x60 [ 3835.073008] [] ? rtnl_newlink+0x13f/0x5f0 [ 3835.073008] [] rtnetlink_rcv_msg+0xa4/0x270 [ 3835.073008] [] ? sock_has_perm+0x75/0x90 [ 3835.073008] [] ? rtnetlink_rcv+0x30/0x30 [ 3835.073008] [] netlink_rcv_skb+0xa9/0xc0 [ 3835.073008] [] rtnetlink_rcv+0x28/0x30 .... modprobe ip_vti ip link del ip_vti0 type vti ip link add ip_vti0 type vti rmmod ip_vti do that one or more times, kernel will panic. fix it by assigning ip_tunnel_dellink to vti_link_ops' dellink, in which we skip the unregister of fb tunnel device. do the same on ip6_vti. Signed-off-by: Xin Long Signed-off-by: Cong Wang Signed-off-by: David S. Miller --- net/ipv4/ip_vti.c | 1 + net/ipv6/ip6_vti.c | 11 +++++++++++ 2 files changed, 12 insertions(+) diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c index 3e861011e4a3..1a7e979e80ba 100644 --- a/net/ipv4/ip_vti.c +++ b/net/ipv4/ip_vti.c @@ -528,6 +528,7 @@ static struct rtnl_link_ops vti_link_ops __read_mostly = { .validate = vti_tunnel_validate, .newlink = vti_newlink, .changelink = vti_changelink, + .dellink = ip_tunnel_dellink, .get_size = vti_get_size, .fill_info = vti_fill_info, }; diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c index 31089d153fd3..bcda14de7f84 100644 --- a/net/ipv6/ip6_vti.c +++ b/net/ipv6/ip6_vti.c @@ -905,6 +905,15 @@ static int vti6_newlink(struct net *src_net, struct net_device *dev, return vti6_tnl_create2(dev); } +static void vti6_dellink(struct net_device *dev, struct list_head *head) +{ + struct net *net = dev_net(dev); + struct vti6_net *ip6n = net_generic(net, vti6_net_id); + + if (dev != ip6n->fb_tnl_dev) + unregister_netdevice_queue(dev, head); +} + static int vti6_changelink(struct net_device *dev, struct nlattr *tb[], struct nlattr *data[]) { @@ -980,6 +989,7 @@ static struct rtnl_link_ops vti6_link_ops __read_mostly = { .setup = vti6_dev_setup, .validate = vti6_validate, .newlink = vti6_newlink, + .dellink = vti6_dellink, .changelink = vti6_changelink, .get_size = vti6_get_size, .fill_info = vti6_fill_info, @@ -1020,6 +1030,7 @@ static int __net_init vti6_init_net(struct net *net) if (!ip6n->fb_tnl_dev) goto err_alloc_dev; dev_net_set(ip6n->fb_tnl_dev, net); + ip6n->fb_tnl_dev->rtnl_link_ops = &vti6_link_ops; err = vti6_fb_tnl_dev_init(ip6n->fb_tnl_dev); if (err < 0)