------------[ cut here ]------------
WARNING: CPU: 3 PID: 9158 at net/netfilter/core.c:329 nf_hook_entry_head+0x230/0x310 net/netfilter/core.c:329
Modules linked in:
CPU: 3 UID: 0 PID: 9158 Comm: kworker/u32:26 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: netns cleanup_net
RIP: 0010:nf_hook_entry_head+0x230/0x310 net/netfilter/core.c:329
Code: 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 dc 00 00 00 4d 3b a5 08 01 00 00 0f 84 07 ff ff ff e8 31 06 41 f8 90 <0f> 0b 90 eb 98 e8 26 06 41 f8 89 ee bf 01 00 00 00 e8 5a 01 41 f8
RSP: 0018:ffffc90003937910 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000005 RCX: ffffffff897be153
RDX: ffff888024e72480 RSI: ffffffff897be19f RDI: ffff8880541f4108
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000002b81 R12: ffff888035632480
R13: ffff8880541f4000 R14: ffff88805406d690 R15: ffff888028a3e33c
FS:  0000000000000000(0000) GS:ffff8880d6d05000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555566fe35c8 CR3: 000000004e5ba000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 __nf_unregister_net_hook+0x81/0x680 net/netfilter/core.c:491
 nf_unregister_net_hook+0xd5/0x110 net/netfilter/core.c:536
 nft_unregister_flowtable_ops net/netfilter/nf_tables_api.c:8979 [inline]
 __nft_unregister_flowtable_net_hooks+0xfc/0x3f0 net/netfilter/nf_tables_api.c:8994
 __nft_release_hook+0x26e/0x350 net/netfilter/nf_tables_api.c:11987
 __nft_release_hooks net/netfilter/nf_tables_api.c:12001 [inline]
 nf_tables_pre_exit_net+0xc5/0x120 net/netfilter/nf_tables_api.c:12152
 ops_pre_exit_list net/core/net_namespace.c:161 [inline]
 ops_undo_list+0x187/0xab0 net/core/net_namespace.c:234
 cleanup_net+0x41b/0x8b0 net/core/net_namespace.c:695
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
 process_scheduled_works kernel/workqueue.c:3346 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>