unregister_netdevice: waiting for syz_tun to become free. Usage count = 4
ref_tracker: syz_tun@ffff888066774608 has 1/3 users at
     __netdev_tracker_alloc include/linux/netdevice.h:4119 [inline]
     netdev_hold include/linux/netdevice.h:4148 [inline]
     dst_init+0xee/0x490 net/core/dst.c:52
     dst_alloc+0x14f/0x190 net/core/dst.c:93
     ip6_dst_alloc net/ipv6/route.c:342 [inline]
     ip6_rt_pcpu_alloc net/ipv6/route.c:1381 [inline]
     rt6_make_pcpu_route net/ipv6/route.c:1430 [inline]
     ip6_pol_route+0xb87/0x15d0 net/ipv6/route.c:2267
     pol_lookup_func include/net/ip6_fib.h:616 [inline]
     fib6_rule_lookup+0x3c2/0x790 net/ipv6/fib6_rules.c:122
     ip6_route_output_flags_noref net/ipv6/route.c:2639 [inline]
     ip6_route_output_flags+0x38e/0x610 net/ipv6/route.c:2651
     ip6_dst_lookup_tail+0x290/0x14f0 net/ipv6/ip6_output.c:1156
     ip6_dst_lookup_flow+0xb9/0x180 net/ipv6/ip6_output.c:1259
     inet6_csk_route_req+0x4a8/0x6d0 net/ipv6/inet6_connection_sock.c:51
     tcp_conn_request+0xd3d/0x34c0 net/ipv4/tcp_input.c:7251
     tcp_rcv_state_process+0x187e/0x44e0 net/ipv4/tcp_input.c:6757
     tcp_v6_do_rcv+0x8bc/0x13a0 net/ipv6/tcp_ipv6.c:1669
     tcp_v6_rcv+0x220a/0x2fb0 net/ipv6/tcp_ipv6.c:1906
     ip6_protocol_deliver_rcu+0xc79/0x1580 net/ipv6/ip6_input.c:436
     ip6_input_finish+0x187/0x2d0 net/ipv6/ip6_input.c:481
     NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314
     NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314

ref_tracker: syz_tun@ffff888066774608 has 1/3 users at
     __netdev_tracker_alloc include/linux/netdevice.h:4119 [inline]
     netdev_tracker_alloc include/linux/netdevice.h:4131 [inline]
     netdev_get_by_index+0x7a/0xb0 net/core/dev.c:916
     fib6_nh_init+0x1d8/0x2180 net/ipv6/route.c:3543
     ip6_route_info_create+0x999/0x12b0 net/ipv6/route.c:3809
     ip6_route_add+0x28/0x160 net/ipv6/route.c:3853
     addrconf_prefix_route net/ipv6/addrconf.c:2486 [inline]
     fixup_permanent_addr net/ipv6/addrconf.c:3603 [inline]
     addrconf_permanent_addr+0x7c7/0xc50 net/ipv6/addrconf.c:3627
     addrconf_notify+0x9f5/0x1020 net/ipv6/addrconf.c:3699
     notifier_call_chain+0x19f/0x3e0 kernel/notifier.c:85
     __dev_notify_flags+0x207/0x400
     dev_change_flags+0xf0/0x1a0 net/core/dev.c:8981
     do_setlink+0xc90/0x4210 net/core/rtnetlink.c:3043
     rtnl_changelink net/core/rtnetlink.c:3646 [inline]
     __rtnl_newlink net/core/rtnetlink.c:3767 [inline]
     rtnl_newlink+0xeec/0x1550 net/core/rtnetlink.c:3887
     rtnetlink_rcv_msg+0x73f/0xcf0 net/core/rtnetlink.c:6799
     netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2556
     netlink_unicast_kernel net/netlink/af_netlink.c:1336 [inline]
     netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1362
     netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1906
     sock_sendmsg_nosec net/socket.c:711 [inline]
     __sock_sendmsg+0x221/0x270 net/socket.c:726

ref_tracker: syz_tun@ffff888066774608 has 1/3 users at
     __netdev_tracker_alloc include/linux/netdevice.h:4119 [inline]
     netdev_hold include/linux/netdevice.h:4148 [inline]
     ipv6_add_dev+0x3f2/0x1220 net/ipv6/addrconf.c:407
     addrconf_notify+0x6a7/0x1020 net/ipv6/addrconf.c:3655
     notifier_call_chain+0x19f/0x3e0 kernel/notifier.c:85
     call_netdevice_notifiers_extack net/core/dev.c:2034 [inline]
     call_netdevice_notifiers net/core/dev.c:2048 [inline]
     register_netdevice+0x167f/0x1b00 net/core/dev.c:10587
     tun_set_iff+0x85c/0xe80 drivers/net/tun.c:2862
     __tun_chr_ioctl+0x863/0x2400 drivers/net/tun.c:3131
     vfs_ioctl fs/ioctl.c:51 [inline]
     __do_sys_ioctl fs/ioctl.c:906 [inline]
     __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
     do_syscall_x64 arch/x86/entry/common.c:52 [inline]
     do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
     entry_SYSCALL_64_after_hwframe+0x77/0x7f