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Kuniyuki IwashimaandPaolo Abeni
00a40d8092
When a lower device is unregistered, its upper ipvlan devices
must also be unregistered. However, these upper devices may
reside in different netns than the lower device.
Let's use unregister_netdevice_queue_net() to support per-netns
device unregistration for ipvlan.
The new dying flag in struct ipvl_dev is used to avoid a race
that ipvlan_link_delete() is called while its lower device is
being removed in ipvlan_device_event().
If dying is true in ipvlan_link_delete(), the ipvlan device is
already destructed but not yet unregistered. In this case,
unregistration will be done in __rtnl_net_unlock() of the
->dellink() caller.
Tested:
1. Create veth in ns1 and two ipvlan devices in ns2 and ns3.
# ip netns add ns1
# ip netns add ns2
# ip netns add ns3
# ip -n ns1 link add veth0 type veth peer veth1
# ip -n ns2 link add ipvl2 link veth0 link-netns ns1 type ipvlan mode l2
# ip -n ns3 link add ipvl3 link veth0 link-netns ns1 type ipvlan mode l2
2. Run bpftrace to check that veth is unregistered first but
wait ipvlan to be unregistered
# bpftrace -e '#include <linux/netdevice.h>
kprobe:ipvlan_uninit,
kprobe:veth_dellink,
kprobe:free_netdev {
$dev = (struct net_device *)arg0;
printf("PID: %d | DEV: %s%s\n", pid, $dev->name, kstack());
}'
3. Remove the lower veth0 in ns1.
# ip -n ns1 link del veth0
We can see that veth0 is freed after unregistering ipvl2 and ipvl3
in per-netns work because ipvl_port holds refcount of veth0.
PID: 2010 | DEV: veth0
veth_dellink+5
rtnl_dellink+1213
rtnetlink_rcv_msg+1791
...
PID: 440 | DEV: ipvl2
ipvlan_uninit+5
unregister_netdevice_many_notify+7129
unregister_netdevice_many_net+1050
rtnl_net_work_func+136
process_scheduled_works+2538
...
PID: 440 | DEV: ipvl2
free_netdev+5
netdev_run_todo+4798
process_scheduled_works+2538
...
PID: 440 | DEV: ipvl3
ipvlan_uninit+5
unregister_netdevice_many_notify+7129
unregister_netdevice_many_net+1050
rtnl_net_work_func+136
process_scheduled_works+2538
...
PID: 2010 | DEV: veth0
free_netdev+5
netdev_run_todo+4798
rtnl_dellink+1507
rtnetlink_rcv_msg+1791
...
PID: 440 | DEV: ipvl3
free_netdev+5
netdev_run_todo+4798
process_scheduled_works+2538
...
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260703001009.1572444-15-kuniyu@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>