On Fri, 06 Dec 2013 15:43:21 -0500 (EST) David Miller <davem@xxxxxxxxxxxxx> wrote: > From: Jiri Pirko <jiri@xxxxxxxxxxx> > Date: Thu, 5 Dec 2013 16:27:37 +0100 > > > br_stp_rcv() is reached by non-rx_handler path. That means there is no > > guarantee that dev is bridge port and therefore simple NULL check of > > ->rx_handler_data is not enough. There is need to check if dev is really > > bridge port and since only rcu read lock is held here, do it by checking > > ->rx_handler pointer. > > > > Note that synchronize_net() in netdev_rx_handler_unregister() ensures > > this approach as valid. > > > > Introduced originally by: > > commit f350a0a87374418635689471606454abc7beaa3a > > "bridge: use rx_handler_data pointer to store net_bridge_port pointer" > > > > Fixed but not in the best way by: > > commit b5ed54e94d324f17c97852296d61a143f01b227a > > "bridge: fix RCU races with bridge port" > > > > Reintroduced by: > > commit 716ec052d2280d511e10e90ad54a86f5b5d4dcc2 > > "bridge: fix NULL pointer deref of br_port_get_rcu" > > > > Please apply to stable trees as well. Thanks. > > > > RH bugzilla reference: https://bugzilla.redhat.com/show_bug.cgi?id=1025770 > > > > Reported-by: Laine Stump <laine@xxxxxxxxxx> > > Debugged-by: Michael S. Tsirkin <mst@xxxxxxxxxx> > > Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> > > Signed-off-by: Jiri Pirko <jiri@xxxxxxxxxxx> > > --- > > v1->v2: moved br_port_get_check_rcu definition below br_handle_frame definition > > Applied and queued up for -stable, thanks Jiri. How come you ignored my simpler fix, that used the existing logic. I don't like introducing this especially into the stable; much prefer to go back to testing the flag as was being done before.
