unregister_netdevice: waiting for lo to become free. Usage count = 2 leaked reference. __netdev_tracker_alloc include/linux/netdevice.h:4020 [inline] netdev_hold include/linux/netdevice.h:4049 [inline] ipv6_add_dev+0x43e/0x1320 net/ipv6/addrconf.c:401 addrconf_notify+0x61e/0x18c0 net/ipv6/addrconf.c:3552 notifier_call_chain+0xb5/0x200 kernel/notifier.c:87 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1944 call_netdevice_notifiers_extack net/core/dev.c:1982 [inline] call_netdevice_notifiers net/core/dev.c:1996 [inline] register_netdevice+0xfb4/0x1640 net/core/dev.c:10078 register_netdev+0x31/0x50 net/core/dev.c:10173 loopback_net_init+0x7a/0x170 drivers/net/loopback.c:219 ops_init+0xb9/0x670 net/core/net_namespace.c:135 setup_net+0x5d1/0xc50 net/core/net_namespace.c:338 copy_net_ns+0x4e9/0x8d0 net/core/net_namespace.c:490 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0xc5/0x1f0 kernel/nsproxy.c:228 ksys_unshare+0x449/0x920 kernel/fork.c:3202 __do_sys_unshare kernel/fork.c:3273 [inline] __se_sys_unshare kernel/fork.c:3271 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:3271 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd