unregister_netdevice: waiting for lo to become free. Usage count = 2
leaked reference.
=====================================================
BUG: KMSAN: uninit-value in __is_kernel include/asm-generic/sections.h:224 [inline]
BUG: KMSAN: uninit-value in is_kernel include/linux/kallsyms.h:36 [inline]
BUG: KMSAN: uninit-value in is_ksym_addr include/linux/kallsyms.h:44 [inline]
BUG: KMSAN: uninit-value in kallsyms_lookup_buildid+0x1fb/0xca0 kernel/kallsyms.c:414
 __is_kernel include/asm-generic/sections.h:224 [inline]
 is_kernel include/linux/kallsyms.h:36 [inline]
 is_ksym_addr include/linux/kallsyms.h:44 [inline]
 kallsyms_lookup_buildid+0x1fb/0xca0 kernel/kallsyms.c:414
 __sprint_symbol+0x166/0x650 kernel/kallsyms.c:527
 sprint_symbol+0x80/0x90 kernel/kallsyms.c:570
 symbol_string+0x44a/0x6e0 lib/vsprintf.c:1000
 pointer+0x17af/0x2970 lib/vsprintf.c:2394
 vsnprintf+0x1d4b/0x3510 lib/vsprintf.c:2800
 vprintk_store+0x571/0x18e0 kernel/printk/printk.c:2243
 vprintk_emit+0x290/0xab0 kernel/printk/printk.c:2340
 vprintk_default+0x8a/0xa0 kernel/printk/printk.c:2370
 vprintk+0x163/0x180 kernel/printk/printk_safe.c:50
 _printk+0x191/0x1e0 kernel/printk/printk.c:2380
 stack_trace_print+0x14e/0x1e0 kernel/stacktrace.c:33
 stack_depot_print+0x59/0x60 lib/stackdepot.c:351
 ref_tracker_dir_print+0x1f9/0x390 lib/ref_tracker.c:57
 netdev_wait_allrefs_any net/core/dev.c:10268 [inline]
 netdev_run_todo+0x1138/0x18f0 net/core/dev.c:10341
 rtnl_unlock+0x17/0x20 net/core/rtnetlink.c:148
 default_device_exit_batch+0xc6e/0xd40 net/core/dev.c:11349
 ops_exit_list net/core/net_namespace.c:174 [inline]
 cleanup_net+0xd77/0x1860 net/core/net_namespace.c:606
 process_one_work+0xe73/0x18d0 kernel/workqueue.c:2289
 worker_thread+0x10fc/0x2230 kernel/workqueue.c:2436
 kthread+0x3c7/0x500 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

Uninit was created at:
 __alloc_pages+0x926/0x10a0 mm/page_alloc.c:5572
 alloc_pages+0xb4b/0xec0
 __stack_depot_save+0x440/0x4b0 lib/stackdepot.c:474
 stack_depot_save+0x17/0x20 lib/stackdepot.c:533
 ref_tracker_alloc+0x31a/0x9a0 lib/ref_tracker.c:92
 __netdev_tracker_alloc include/linux/netdevice.h:4020 [inline]
 netdev_tracker_alloc+0xe6/0x140 include/linux/netdevice.h:4032
 fib_create_info+0x4689/0x4870 net/ipv4/fib_semantics.c:1547
 fib_table_insert+0x3b2/0x3a00 net/ipv4/fib_trie.c:1236
 fib_magic+0x67c/0x880 net/ipv4/fib_frontend.c:1101
 fib_add_ifaddr+0x2b6/0xb10 net/ipv4/fib_frontend.c:1123
 fib_inetaddr_event+0x24b/0x6c0 net/ipv4/fib_frontend.c:1437
 notifier_call_chain kernel/notifier.c:87 [inline]
 blocking_notifier_call_chain+0x178/0x350 kernel/notifier.c:382
 __inet_insert_ifa+0x134b/0x1450 net/ipv4/devinet.c:555
 inet_rtm_newaddr+0x14be/0x2780 net/ipv4/devinet.c:961
 rtnetlink_rcv_msg+0x162a/0x1ab0 net/core/rtnetlink.c:6141
 netlink_rcv_skb+0x6de/0x800 net/netlink/af_netlink.c:2574
 rtnetlink_rcv+0x54/0x60 net/core/rtnetlink.c:6159
 netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
 netlink_unicast+0x10a0/0x1370 net/netlink/af_netlink.c:1365
 netlink_sendmsg+0x13aa/0x1700 net/netlink/af_netlink.c:1942
 sock_sendmsg_nosec net/socket.c:714 [inline]
 sock_sendmsg net/socket.c:734 [inline]
 __sys_sendto+0xa10/0xc90 net/socket.c:2117
 __se_compat_sys_socketcall+0x10eb/0x1770 net/compat.c:422
 __ia32_compat_sys_socketcall+0x95/0xc0 net/compat.c:422
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x37/0x80 arch/x86/entry/common.c:203
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/common.c:246
 entry_SYSENTER_compat_after_hwframe+0x70/0x82

CPU: 0 PID: 3515 Comm: kworker/u4:17 Not tainted 6.2.0-rc8-syzkaller-80999-g31b504f219a9 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/21/2023
Workqueue: netns cleanup_net
=====================================================