------------[ cut here ]------------
WARNING: CPU: 3 PID: 1151 at net/ipv6/xfrm6_tunnel.c:341 xfrm6_tunnel_net_exit+0x9f/0x160 net/ipv6/xfrm6_tunnel.c:341
Modules linked in:
CPU: 3 UID: 0 PID: 1151 Comm: kworker/u32:9 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:xfrm6_tunnel_net_exit+0x9f/0x160 net/ipv6/xfrm6_tunnel.c:341
Code: 00 00 00 49 8d 3c dc 48 89 f8 48 c1 e8 03 42 80 3c 28 00 0f 85 bd 00 00 00 89 e8 49 8b 04 c4 48 85 c0 74 ab e8 22 49 9e f7 90 <0f> 0b 90 eb a0 4d 8d ac 24 00 08 00 00 31 db 49 be 00 00 00 00 00
RSP: 0018:ffffc90006d9fa90 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: fffff52000db3f23
RDX: ffff8880227a2480 RSI: ffffffff8a1e0e5e RDI: ffff88804d6f8000
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff90824cd7 R11: 0000000000000001 R12: ffff88804d6f8000
R13: dffffc0000000000 R14: fffffbfff205e6e8 R15: ffffffff902f3720
FS:  0000000000000000(0000) GS:ffff888097b0d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000057bfd4c0 CR3: 0000000076639000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 ops_exit_list net/core/net_namespace.c:199 [inline]
 ops_undo_list+0x2ee/0xab0 net/core/net_namespace.c:252
 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>