On Mon, 4 Aug 2014 11:37:56 +0800 <lichu...@huawei.com> wrote: > From: Chunhe Li <lichu...@huawei.com> > > In the br_hanle_frame function has a bug, when the bridge receive packets > which go througth the br_handle_frame, get the net_bridge_port pointer "p", > but don't check NULL pointer to use it. If somebody delete the bridge port > at the same time, will call a NULL pointer, trigger kernel panic. I see the > del_nbp comments, call del_nbp should via RCU, but the caller don't do this. > > following steps will make bug happened > 1.start vm and add the vm interface to a bridge br0,for example, > brctl addbr br0 tap0 > > 2.configuer vm interface and br0 same ip subnet, vm ping br0. > > 3.add and delete the vm interface port for endless loop. > > Signed-off-by: Chunhe Li <lichu...@huawei.com>
This is safe because: 1. br_dev_delete is called with RTNL mutex therefore it is safe with other add/delete RCU does not block anything 2. br_handle_frame is called with RCU lock (in frame rx) 3. port is not freed until after grace period -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/