=====================================================
BUG: KMSAN: uninit-value in ref_tracker_free+0x5ca/0xec0 lib/ref_tracker.c:228
 ref_tracker_free+0x5ca/0xec0 lib/ref_tracker.c:228
 netdev_tracker_free include/linux/netdevice.h:4295 [inline]
 netdev_put include/linux/netdevice.h:4312 [inline]
 neigh_parms_release+0x212/0x3d0 net/core/neighbour.c:1711
 addrconf_ifdown+0x2f4a/0x3240 net/ipv6/addrconf.c:4003
 addrconf_notify+0x18f/0x1c40 net/ipv6/addrconf.c:3772
 notifier_call_chain kernel/notifier.c:85 [inline]
 raw_notifier_call_chain+0xe8/0x440 kernel/notifier.c:453
 call_netdevice_notifiers_info+0x1be/0x2b0 net/core/dev.c:2141
 call_netdevice_notifiers_extack net/core/dev.c:2179 [inline]
 call_netdevice_notifiers net/core/dev.c:2193 [inline]
 unregister_netdevice_many_notify+0x1fbf/0x3e30 net/core/dev.c:11809
 unregister_netdevice_many+0x22/0x30 net/core/dev.c:11875
 cleanup_net+0xf02/0x1d20 net/core/net_namespace.c:647
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xae0/0x1c40 kernel/workqueue.c:3317
 worker_thread+0xea7/0x14f0 kernel/workqueue.c:3398
 kthread+0x6b9/0xef0 kernel/kthread.c:464
 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Uninit was created at:
 __alloc_frozen_pages_noprof+0x9a7/0xe00 mm/page_alloc.c:4762
 alloc_pages_mpol+0x4cd/0x890 mm/mempolicy.c:2270
 alloc_frozen_pages_noprof+0x1bf/0x1e0 mm/mempolicy.c:2341
 alloc_slab_page mm/slub.c:2423 [inline]
 allocate_slab+0x23a/0x1110 mm/slub.c:2587
 new_slab mm/slub.c:2640 [inline]
 ___slab_alloc+0x1287/0x3540 mm/slub.c:3826
 __slab_alloc mm/slub.c:3916 [inline]
 __slab_alloc_node mm/slub.c:3991 [inline]
 slab_alloc_node mm/slub.c:4152 [inline]
 __do_kmalloc_node mm/slub.c:4293 [inline]
 __kmalloc_noprof+0xa59/0x1230 mm/slub.c:4306
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1037 [inline]
 new_dir fs/proc/proc_sysctl.c:962 [inline]
 get_subdir fs/proc/proc_sysctl.c:1006 [inline]
 sysctl_mkdir_p fs/proc/proc_sysctl.c:1316 [inline]
 __register_sysctl_table+0x1bcb/0x2e30 fs/proc/proc_sysctl.c:1391
 register_net_sysctl_sz+0x3f5/0x410 net/sysctl_net.c:171
 neigh_sysctl_register+0x755/0x980 net/core/neighbour.c:3795
 devinet_sysctl_register+0x167/0x400 net/ipv4/devinet.c:2667
 inetdev_init+0x561/0x8e0 net/ipv4/devinet.c:299
 inetdev_event+0xbec/0x1e60 net/ipv4/devinet.c:1598
 notifier_call_chain kernel/notifier.c:85 [inline]
 raw_notifier_call_chain+0xe8/0x440 kernel/notifier.c:453
 call_netdevice_notifiers_info+0x1be/0x2b0 net/core/dev.c:2141
 call_netdevice_notifiers_extack net/core/dev.c:2179 [inline]
 call_netdevice_notifiers net/core/dev.c:2193 [inline]
 register_netdevice+0x2124/0x22f0 net/core/dev.c:10915
 tun_set_iff+0xe71/0x16c0 drivers/net/tun.c:2866
 __tun_chr_ioctl+0x2506/0x3bb0 drivers/net/tun.c:3135
 tun_chr_ioctl+0x43/0x50 drivers/net/tun.c:3422
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0x246/0x440 fs/ioctl.c:892
 __x64_sys_ioctl+0x96/0xe0 fs/ioctl.c:892
 x64_sys_call+0x19f0/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 UID: 0 PID: 3953 Comm: kworker/u8:20 Not tainted 6.13.0-syzkaller-09338-g05dbaf8dd8bf #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: netns cleanup_net
=====================================================