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
 __netns_tracker_alloc include/net/net_namespace.h:331 [inline]
 sk_alloc+0x9f1/0xa90 net/core/sock.c:2108
 __netlink_create net/netlink/af_netlink.c:649 [inline]
 __netlink_kernel_create+0x30a/0x11f0 net/netlink/af_netlink.c:2066
 netlink_kernel_create include/linux/netlink.h:62 [inline]
 rtnetlink_net_init+0xa7/0x180 net/core/rtnetlink.c:6217
 ops_init+0x399/0x970 net/core/net_namespace.c:135
 setup_net+0x7d5/0x19c0 net/core/net_namespace.c:333
 copy_net_ns+0x85a/0xc90 net/core/net_namespace.c:483
 create_new_namespaces+0x8ff/0xfb0 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x262/0x340 kernel/nsproxy.c:228
 ksys_unshare+0xa98/0x1580 kernel/fork.c:3202
 __do_sys_unshare kernel/fork.c:3273 [inline]
 __se_sys_unshare kernel/fork.c:3271 [inline]
 __x64_sys_unshare+0x5d/0x80 kernel/fork.c:3271
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

CPU: 0 PID: 3586 Comm: kworker/u4:19 Not tainted 6.2.0-rc8-syzkaller-80994-gda13c00eebfb #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/21/2023
Workqueue: netns cleanup_net
=====================================================