Re:Re: [drivers/net/vxlan]Why rcu_read_lock is not obtained before rculist travelling

Hi Cong,

Thanks very much for your reply.  It's indeeded acquired by upper layer.

Thanks

At 2017-03-01 05:29:17, "Cong Wang" [off-list ref] wrote:

On Tue, Feb 28, 2017 at 6:03 AM, Xiaobo Yan [off-list ref] wrote:

quoted

But I don’t find any rcu_read_lock invoked before travelling fdb_head list.  In vxlan_xmit and vxlan_snoop function, vxlan_find_mac function is called to search the vxlan_fdb of the dst_mac or src_mac. Then information in vxlan_fdb  is used for further process.  But as no rcu_read_lock is obtained before the list travelling, I am wondering if it is possible that vxlan_fdb is freed when it is being used.

In both RX and TX paths, rcu read lock is acquired by upper layer.
Check __dev_queue_xmit() and process_backlog().