On Sat, Mar 18, 2017 at 6:48 PM, Kevin Xu <kaiwen...@hulu.com> wrote: > In some rare cases, inet_sk_rx_dst_set() may be called multiple times > on the same dst, causing double refcounting. Eventually, it > prevents net_device to be destroyed. The bug manifested as > > unregister_netdevice: waiting for lo to become free. Usage count = 1 > > in the kernel log, preventing new network namespace creation. > > Signed-off-by: Kevin Xu <kaiwen...@hulu.com>
Don't know why you don't follow the discussion on your v1... It is protected by bh_lock_sock(), so your patch is not needed at all. Read net/ipv4/udp.c: 1762 /* For TCP sockets, sk_rx_dst is protected by socket lock 1763 * For UDP, we use xchg() to guard against concurrent changes. 1764 */
