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+0x99a/0x2000 net/ipv6/addrconf.c:401
 addrconf_notify+0x9c0/0x1e50 net/ipv6/addrconf.c:3552
 notifier_call_chain kernel/notifier.c:87 [inline]
 raw_notifier_call_chain+0x11b/0x2a0 kernel/notifier.c:455
=====================================================
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

Local variable name created at:
 __fsnotify_parent+0x24b/0x10a0 fs/notify/fsnotify.c:189
 fsnotify_parent include/linux/fsnotify.h:77 [inline]
 fsnotify_file include/linux/fsnotify.h:99 [inline]
 fsnotify_modify include/linux/fsnotify.h:317 [inline]
 do_iter_write+0x163d/0x1800 fs/read_write.c:865

CPU: 1 PID: 27 Comm: kworker/u4:1 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
=====================================================