From b3f1be4b5412e34647764457bec901e06b03e624 Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Thu, 9 Feb 2006 17:08:52 -0800 Subject: [BRIDGE]: fix for RCU and deadlock on device removal Change Bridge receive path to correctly handle RCU removal of device from bridge. Also fixes deadlock between carrier_check and del_nbp. This replaces the previous deleted flag fix. Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller --- net/bridge/br_stp_bpdu.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-) (limited to 'net/bridge/br_stp_bpdu.c') diff --git a/net/bridge/br_stp_bpdu.c b/net/bridge/br_stp_bpdu.c index d071f1c9ad0b..296f6a487c52 100644 --- a/net/bridge/br_stp_bpdu.c +++ b/net/bridge/br_stp_bpdu.c @@ -133,29 +133,35 @@ void br_send_tcn_bpdu(struct net_bridge_port *p) static const unsigned char header[6] = {0x42, 0x42, 0x03, 0x00, 0x00, 0x00}; -/* NO locks */ +/* NO locks, but rcu_read_lock (preempt_disabled) */ int br_stp_handle_bpdu(struct sk_buff *skb) { - struct net_bridge_port *p = skb->dev->br_port; - struct net_bridge *br = p->br; + struct net_bridge_port *p = rcu_dereference(skb->dev->br_port); + struct net_bridge *br; unsigned char *buf; + if (!p) + goto err; + + br = p->br; + spin_lock(&br->lock); + + if (p->state == BR_STATE_DISABLED || !(br->dev->flags & IFF_UP)) + goto out; + /* insert into forwarding database after filtering to avoid spoofing */ - br_fdb_update(p->br, p, eth_hdr(skb)->h_source); + br_fdb_update(br, p, eth_hdr(skb)->h_source); + + if (!br->stp_enabled) + goto out; /* need at least the 802 and STP headers */ if (!pskb_may_pull(skb, sizeof(header)+1) || memcmp(skb->data, header, sizeof(header))) - goto err; + goto out; buf = skb_pull(skb, sizeof(header)); - spin_lock_bh(&br->lock); - if (p->state == BR_STATE_DISABLED - || !(br->dev->flags & IFF_UP) - || !br->stp_enabled) - goto out; - if (buf[0] == BPDU_TYPE_CONFIG) { struct br_config_bpdu bpdu; @@ -201,7 +207,7 @@ int br_stp_handle_bpdu(struct sk_buff *skb) br_received_tcn_bpdu(p); } out: - spin_unlock_bh(&br->lock); + spin_unlock(&br->lock); err: kfree_skb(skb); return 0; -- cgit v1.2.3-59-g8ed1b