From 158cd4af8dedbda0d612d448c724c715d0dda649 Mon Sep 17 00:00:00 2001 From: Lars Westerhoff Date: Tue, 28 Jul 2015 01:32:21 +0300 Subject: [PATCH] packet: missing dev_put() in packet_do_bind() When binding a PF_PACKET socket, the use count of the bound interface is always increased with dev_hold in dev_get_by_{index,name}. However, when rebound with the same protocol and device as in the previous bind the use count of the interface was not decreased. Ultimately, this caused the deletion of the interface to fail with the following message: unregister_netdevice: waiting for dummy0 to become free. Usage count = 1 This patch moves the dev_put out of the conditional part that was only executed when either the protocol or device changed on a bind. Fixes: 902fefb82ef7 ('packet: improve socket create/bind latency in some cases') Signed-off-by: Lars Westerhoff Signed-off-by: Dan Carpenter Reviewed-by: Daniel Borkmann Signed-off-by: David S. Miller --- net/packet/af_packet.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index c9e8741226c6..c7c42eb617ef 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2784,7 +2784,7 @@ static int packet_release(struct socket *sock) static int packet_do_bind(struct sock *sk, struct net_device *dev, __be16 proto) { struct packet_sock *po = pkt_sk(sk); - const struct net_device *dev_curr; + struct net_device *dev_curr; __be16 proto_curr; bool need_rehook; @@ -2808,15 +2808,13 @@ static int packet_do_bind(struct sock *sk, struct net_device *dev, __be16 proto) po->num = proto; po->prot_hook.type = proto; - - if (po->prot_hook.dev) - dev_put(po->prot_hook.dev); - po->prot_hook.dev = dev; po->ifindex = dev ? dev->ifindex : 0; packet_cached_dev_assign(po, dev); } + if (dev_curr) + dev_put(dev_curr); if (proto == 0 || !need_rehook) goto out_unlock; -- 2.20.1