HI Eric the problem is as follow: br_del_if()-->del_nbp(): list_del_rcu(&p->list); dev->priv_flags &= ~IFF_BRIDGE_PORT;
------>at this point, the nic be deleting still have rx_handler , so , may in br_handle_frame() ------>br_port_exists() will return false,so br_get_port_rcu() will return NULL ------>so in br_handle_frame , there will be a null panic. netdev_rx_handler_unregister(dev); synchronize_net(); i have checked commit 00cfec37484761a44, i think it didn't fix this bug.. thanks. On Thu, Jun 20, 2013 at 12:55 PM, Eric Dumazet <[email protected]>wrote: > On Thu, 2013-06-20 at 11:08 +0800, xiaoming gao wrote: > > From: newtongao <[email protected]> > > Date: Wed, 19 Jun 2013 14:58:33 +0800 > > Subject: [PATCH] net bridge: add null pointer check,fix panic > > > > in kernel 3.0, br_port_get_rcu() may return NULL when network interface > be deleting from bridge, > > but in function br_handle_frame and br_handle_local_finish, the pointer > didn't be checked before using, > > so all br_port_get_rcu callers must do null check,or there occurs the > null pointer panic. > > > > kernel 3.4 also has this bug,i have verified. > > mainline kernel still did not check br_port_get_rcu()'s NULL pointer, > but i have not tested it yet. > > Please check current version before sending a patch. > > This was most probably fixed in commit 00cfec37484761a44 > ("net: add a synchronize_net() in netdev_rx_handler_unregister()") > > Thanks > > >
