unregister_netdevice: waiting for netdevsim0 to become free. Usage count = 2
ref_tracker: netdev@ffff88805a7ac618 has 1/1 users at
     xfrm_dev_state_add+0x6e7/0xc30 net/xfrm/xfrm_device.c:316
     xfrm_state_construct net/xfrm/xfrm_user.c:986 [inline]
     xfrm_add_sa+0x34ca/0x4230 net/xfrm/xfrm_user.c:1022
     xfrm_user_rcv_msg+0x746/0xb20 net/xfrm/xfrm_user.c:3507
     netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550
     xfrm_netlink_rcv+0x79/0x90 net/xfrm/xfrm_user.c:3529
     netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
     netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1344
     netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894
     sock_sendmsg_nosec net/socket.c:727 [inline]
     __sock_sendmsg net/socket.c:742 [inline]
     ____sys_sendmsg+0xa68/0xad0 net/socket.c:2592
     ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646
     __sys_sendmsg net/socket.c:2678 [inline]
     __do_sys_sendmsg net/socket.c:2683 [inline]
     __se_sys_sendmsg net/socket.c:2681 [inline]
     __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681
     do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
     do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
     entry_SYSCALL_64_after_hwframe+0x77/0x7f