From: Jiri Pirko Date: Thu, 5 Dec 2013 15:27:37 +0000 (+0100) Subject: br: fix use of ->rx_handler_data in code executed on non-rx_handler path X-Git-Tag: v3.13-rc4~3^2~43 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=859828c0ea476b42f3a93d69d117aaba90994b6f;p=pandora-kernel.git br: fix use of ->rx_handler_data in code executed on non-rx_handler path 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 Debugged-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Signed-off-by: Jiri Pirko Acked-by: Michael S. Tsirkin Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- Reading git-diff-tree failed