From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: br_forward.c - rcu dereference warning Date: Tue, 27 Jul 2010 13:42:23 -0700 Message-ID: <20100727134223.5bb0be30@nehalam> References: <1280227553.3755.2.camel@jlt3.sipsolutions.net> <20100727123859.GF3766@linux.vnet.ibm.com> <20100727112630.5a5ce84b@nehalam> <1280261679.3755.6.camel@jlt3.sipsolutions.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: paulmck@linux.vnet.ibm.com, netdev To: Johannes Berg Return-path: Received: from mail.vyatta.com ([76.74.103.46]:56509 "EHLO mail.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751031Ab0G0Um1 (ORCPT ); Tue, 27 Jul 2010 16:42:27 -0400 In-Reply-To: <1280261679.3755.6.camel@jlt3.sipsolutions.net> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, 27 Jul 2010 22:14:39 +0200 Johannes Berg wrote: > On Tue, 2010-07-27 at 11:26 -0700, Stephen Hemminger wrote: > > > -/* net device transmit always called with no BH (preempt_disabled) */ > > +/* net device transmit always called with no BH disabled */ > > "no BH disabled"? > > > @@ -48,6 +48,7 @@ netdev_tx_t br_dev_xmit(struct sk_buff * > > skb_reset_mac_header(skb); > > skb_pull(skb, ETH_HLEN); > > > > + rcu_read_lock(); > > if (is_multicast_ether_addr(dest)) { > > if (unlikely(netpoll_tx_running(dev))) { > > br_flood_deliver(br, skb); > > @@ -67,6 +68,7 @@ netdev_tx_t br_dev_xmit(struct sk_buff * > > br_flood_deliver(br, skb); > > > > out: > > + rcu_read_unlock(); > > return NETDEV_TX_OK; > > } > > > > --- a/net/bridge/br_fdb.c 2010-07-27 11:18:30.815320981 -0700 > > +++ b/net/bridge/br_fdb.c 2010-07-27 11:18:59.597710975 -0700 > > @@ -214,7 +214,7 @@ void br_fdb_delete_by_port(struct net_br > > spin_unlock_bh(&br->hash_lock); > > } > > > > -/* No locking or refcounting, assumes caller has no preempt (rcu_read_lock) */ > > +/* No locking or refcounting, assumes caller has rcu_read_lock */ > > struct net_bridge_fdb_entry *__br_fdb_get(struct net_bridge *br, > > const unsigned char *addr) > > { > > --- a/net/bridge/br_input.c 2010-07-27 11:19:05.266181492 -0700 > > +++ b/net/bridge/br_input.c 2010-07-27 11:19:29.148163149 -0700 > > @@ -39,7 +39,7 @@ static int br_pass_frame_up(struct sk_bu > > netif_receive_skb); > > } > > > > -/* note: already called with rcu_read_lock (preempt_disabled) */ > > +/* note: already called with rcu_read_lock */ > > int br_handle_frame_finish(struct sk_buff *skb) > > { > > const unsigned char *dest = eth_hdr(skb)->h_dest; > > @@ -110,7 +110,7 @@ drop: > > goto out; > > } > > > > -/* note: already called with rcu_read_lock (preempt_disabled) */ > > +/* note: already called with rcu_read_lock */ > > static int br_handle_local_finish(struct sk_buff *skb) > > { > > struct net_bridge_port *p = br_port_get_rcu(skb->dev); > > @@ -133,8 +133,7 @@ static inline int is_link_local(const un > > > > /* > > * Return NULL if skb is handled > > - * note: already called with rcu_read_lock (preempt_disabled) from > > - * netif_receive_skb > > + * note: already called with rcu_read_lock from netif_receive_skb > > */ > > struct sk_buff *br_handle_frame(struct sk_buff *skb) > > { > > --- a/net/bridge/br_stp_bpdu.c 2010-07-27 11:19:34.092573294 -0700 > > +++ b/net/bridge/br_stp_bpdu.c 2010-07-27 11:19:40.725123403 -0700 > > @@ -131,7 +131,7 @@ void br_send_tcn_bpdu(struct net_bridge_ > > /* > > * Called from llc. > > * > > - * NO locks, but rcu_read_lock (preempt_disabled) > > + * NO locks, but rcu_read_lock > > */ > > void br_stp_rcv(const struct stp_proto *proto, struct sk_buff *skb, > > struct net_device *dev) > > > > Did you want me to test the patch? Yes please, I can make sure it works, but not that it gets rid of your error --