WARNING in __nf_unregister_net

similar bugs (3):
Kernel	Title	Repro	Cause bisect	Count	Last	Reported	Patched	Status
upstream	WARNING in __nf_unregister_net_hook (4)	C	error	66	81d	411d	22/22	fixed on 2022/03/08 16:11
upstream	WARNING in __nf_unregister_net_hook			1	763d	759d	0/22	auto-closed as invalid on 2020/06/22 17:41
upstream	WARNING in __nf_unregister_net_hook (2)	C	done	9	683d	682d	17/22	fixed on 2020/09/16 22:51

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hook not found, pf 10 num 3
WARNING: CPU: 1 PID: 3575 at net/netfilter/core.c:413 __nf_unregister_net_hook+0x1eb/0x500 net/netfilter/core.c:413
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 3575 Comm: kworker/u4:6 Not tainted 5.9.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x198/0x1fd lib/dump_stack.c:118
 panic+0x347/0x7c0 kernel/panic.c:231
 __warn.cold+0x20/0x46 kernel/panic.c:600
 report_bug+0x1bd/0x210 lib/bug.c:198
 handle_bug+0x38/0x90 arch/x86/kernel/traps.c:234
 exc_invalid_op+0x14/0x40 arch/x86/kernel/traps.c:254
 asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:536
RIP: 0010:__nf_unregister_net_hook+0x1eb/0x500 net/netfilter/core.c:413
Code: 0f b6 14 02 48 89 c8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 09 03 00 00 8b 53 1c 89 ee 48 c7 c7 c0 a8 04 89 e8 27 9b cc fa <0f> 0b e9 b1 00 00 00 e8 19 9a fb fa 44 8b 3c 24 4c 89 f8 48 c1 e0
RSP: 0018:ffffc9000737fb78 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffffffff890d9ec8 RCX: 0000000000000000
RDX: ffff88809a0b6080 RSI: ffffffff815dba07 RDI: fffff52000e6ff61
RBP: 000000000000000a R08: 0000000000000001 R09: ffffffff8c5f4a27
R10: 0000000000001432 R11: 0000000000000001 R12: ffff888090c39048
R13: 0000000000000000 R14: ffff888000100380 R15: 0000000000000001
 nf_unregister_net_hook net/netfilter/core.c:431 [inline]
 nf_unregister_net_hooks+0x47/0xe0 net/netfilter/core.c:499
 defrag6_net_exit net/ipv6/netfilter/nf_defrag_ipv6_hooks.c:93 [inline]
 defrag6_net_exit+0x6f/0xc0 net/ipv6/netfilter/nf_defrag_ipv6_hooks.c:90
 ops_exit_list+0xb0/0x160 net/core/net_namespace.c:186
 cleanup_net+0x4ea/0xa00 net/core/net_namespace.c:603
 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Kernel Offset: disabled
Rebooting in 86400 seconds..