------------[ cut here ]------------
WARNING: CPU: 1 PID: 10 at net/core/dev.c:10994 unregister_netdevice_many+0x207/0x1790 net/core/dev.c:10994
Modules linked in:
CPU: 1 PID: 10 Comm: kworker/u4:1 Not tainted 5.14.0-rc4-next-20210806-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
RIP: 0010:unregister_netdevice_many+0x207/0x1790 net/core/dev.c:10994
Code: 05 00 00 31 ff 44 89 fe e8 f6 09 5c fa 45 84 ff 0f 85 49 ff ff ff e8 a8 03 5c fa 0f 1f 44 00 00 e8 9e 03 5c fa e8 99 03 5c fa <0f> 0b 4c 89 ef e8 1f 2f bf fc 31 ff 41 89 c5 89 c6 e8 c3 09 5c fa
RSP: 0018:ffffc90000cf7a70 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff888000110000 RCX: 0000000000000000
RDX: ffff888011ac1c80 RSI: ffffffff8719c5c7 RDI: 0000000000000003
RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff8719c5aa R11: 0000000000000000 R12: ffff8880322ca000
R13: ffff888000110060 R14: ffffc90000cf7ae0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000542978 CR3: 000000001af4d000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 ip_tunnel_delete_nets+0x39f/0x5b0 net/ipv4/ip_tunnel.c:1123
 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:178
 cleanup_net+0x4ea/0xb10 net/core/net_namespace.c:595
 process_one_work+0x98d/0x1630 kernel/workqueue.c:2276
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2422
 kthread+0x3e5/0x4d0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295