bareudp_exit_rtnl_net() iterates bareudp devices whose sockets
are in the dying netns and queues them for destruction.
So the devices may reside in different netns.
Let's use unregister_netdevice_queue_net() to support per-netns
device unregistration.
list_del() is changed to list_del_init() to avoid queueing the
same device twice.
Even after bareudp_exit_rtnl_net() queues a cross-netns bareudp
device, bareudp_dellink() could be called concurrently for it
(once RTNL is removed). In such a case, __rtnl_net_unlock() will
perform the unregistration.
Note that bareudp uses register_pernet_subsys() instead of _device(),
so default_device_exit_batch() guarantees that the async per-netns
works are flushed before ->exit().
Tested:
1. Create bareudp device across two netns.
# ip netns add ns1
# ip netns add ns2
# ip -n ns1 link add bareudp0 link-netns ns2 type bareudp \
dstport 9292 ethertype ipv4
2. Run bpftrace to check that bareudp_uninit() is called between
->exit_rtnl() and ->exit().
# bpftrace -e '#include <linux/netdevice.h>
kprobe:bareudp_uninit {
$dev = (struct net_device *)arg0;
printf("PID: %d | DEV: %s%s\n", pid, $dev->name, kstack());
}
kprobe:bareudp_exit_rtnl_net,
kprobe:bareudp_exit_net {
printf("PID: %d%s\n", pid, kstack());
}'
3. Remove the netns where the bareudp socket resides
# ip netns del ns2
Now, we can see bareudp0 is unregistered by per-netns work
instead of cleanup_net() and it finishes before ->exit() to
avoid WARN_ON_ONCE(!list_empty(&bn->bareudp_list)) there.
PID: 576
bareudp_exit_rtnl_net+5
ops_undo_list+702
cleanup_net+1122
process_scheduled_works+2538
...
PID: 470 | DEV: bareudp0
bareudp_uninit+5
unregister_netdevice_many_notify+7129
unregister_netdevice_many_net+1050
rtnl_net_work_func+136
process_scheduled_works+2538
...
PID: 576
bareudp_exit_net+5
ops_undo_list+1064
cleanup_net+1122
process_scheduled_works+2538
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260703001009.1572444-11-kuniyu@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
f1de92507a