From 0d7a7b2014b1a499a0fe24c9f3063d7856b5aaaf Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 31 Mar 2021 14:38:11 -0700 Subject: [PATCH] ipv6: remove extra dev_hold() for fallback tunnels My previous commits added a dev_hold() in tunnels ndo_init(), but forgot to remove it from special functions setting up fallback tunnels. Fallback tunnels do call their respective ndo_init() This leads to various reports like : unregister_netdevice: waiting for ip6gre0 to become free. Usage count = 2 Fixes: 48bb5697269a ("ip6_tunnel: sit: proper dev_{hold|put} in ndo_[un]init methods") Fixes: 6289a98f0817 ("sit: proper dev_{hold|put} in ndo_[un]init methods") Fixes: 40cb881b5aaa ("ip6_vti: proper dev_{hold|put} in ndo_[un]init methods") Fixes: 7f700334be9a ("ip6_gre: proper dev_{hold|put} in ndo_[un]init methods") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller --- net/ipv6/ip6_gre.c | 3 --- net/ipv6/ip6_tunnel.c | 1 - net/ipv6/ip6_vti.c | 1 - net/ipv6/sit.c | 1 - 4 files changed, 6 deletions(-) diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c index 9689bf9f46f3..bc224f917bbd 100644 --- a/net/ipv6/ip6_gre.c +++ b/net/ipv6/ip6_gre.c @@ -387,7 +387,6 @@ static struct ip6_tnl *ip6gre_tunnel_locate(struct net *net, if (!(nt->parms.o_flags & TUNNEL_SEQ)) dev->features |= NETIF_F_LLTX; - dev_hold(dev); ip6gre_tunnel_link(ign, nt); return nt; @@ -1539,8 +1538,6 @@ static void ip6gre_fb_tunnel_init(struct net_device *dev) strcpy(tunnel->parms.name, dev->name); tunnel->hlen = sizeof(struct ipv6hdr) + 4; - - dev_hold(dev); } static struct inet6_protocol ip6gre_protocol __read_mostly = { diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c index 67ee9d58ec5e..07a0a06a9b52 100644 --- a/net/ipv6/ip6_tunnel.c +++ b/net/ipv6/ip6_tunnel.c @@ -1925,7 +1925,6 @@ static int __net_init ip6_fb_tnl_dev_init(struct net_device *dev) struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id); t->parms.proto = IPPROTO_IPV6; - dev_hold(dev); rcu_assign_pointer(ip6n->tnls_wc[0], t); return 0; diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c index a018afdb3e06..856e46ad0895 100644 --- a/net/ipv6/ip6_vti.c +++ b/net/ipv6/ip6_vti.c @@ -963,7 +963,6 @@ static int __net_init vti6_fb_tnl_dev_init(struct net_device *dev) struct vti6_net *ip6n = net_generic(net, vti6_net_id); t->parms.proto = IPPROTO_IPV6; - dev_hold(dev); rcu_assign_pointer(ip6n->tnls_wc[0], t); return 0; diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c index 488d3181aec3..ff2ca2e7c7f5 100644 --- a/net/ipv6/sit.c +++ b/net/ipv6/sit.c @@ -1470,7 +1470,6 @@ static void __net_init ipip6_fb_tunnel_init(struct net_device *dev) iph->ihl = 5; iph->ttl = 64; - dev_hold(dev); rcu_assign_pointer(sitn->tunnels_wc[0], tunnel); }