------------[ cut here ]------------
sk->sk_forward_alloc
WARNING: net/ipv4/af_inet.c:162 at inet_sock_destruct+0x62d/0x740, CPU#0: syz.1.278/6842
Modules linked in:
CPU: 0 UID: 0 PID: 6842 Comm: syz.1.278 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:inet_sock_destruct+0x62d/0x740
Code: 0f 0b 90 e9 58 fe ff ff e8 60 05 9e f7 90 0f 0b 90 e9 8b fe ff ff e8 52 05 9e f7 90 0f 0b 90 e9 b1 fe ff ff e8 44 05 9e f7 90 <0f> 0b 90 e9 d7 fe ff ff 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c 95 fc
RSP: 0018:ffffc90000007d40 EFLAGS: 00010246
RAX: ffffffff8a27bf7c RBX: dffffc0000000000 RCX: ffff888199d48000
RDX: 0000000000000100 RSI: 0000000000000f70 RDI: 0000000000000000
RBP: 0000000000000f70 R08: ffff888168e5be27 R09: 1ffff1102d1cb7c4
R10: dffffc0000000000 R11: ffffed102d1cb7c5 R12: ffff888168e5bb80
R13: ffff888168e5c088 R14: ffff888168e5be0c R15: ffffffff8feb0900
FS:  000055556a4c2500(0000) GS:ffff88818dc87000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe7455e8158 CR3: 000000016c2ae000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 __sk_destruct+0x8d/0x9d0
 rcu_core+0x7cd/0x1070
 handle_softirqs+0x22a/0x840
 do_softirq+0x76/0xd0
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0xf8/0x130
 __fib6_clean_all+0x464/0x5a0
 rt6_disable_ip+0x128/0x730
 addrconf_ifdown+0x161/0x1a40
 addrconf_notify+0x1bc/0x1050
 notifier_call_chain+0x1ad/0x3d0
 unregister_netdevice_many_notify+0x17a5/0x22c0
 vlan_device_event+0x1dd5/0x1f10
 notifier_call_chain+0x1ad/0x3d0
 unregister_netdevice_many_notify+0x17a5/0x22c0
 unregister_netdevice_queue+0x31f/0x360
 __tun_detach+0x6d9/0x15d0
 tun_chr_close+0x10a/0x1c0
 __fput+0x44f/0xa60
 task_work_run+0x1d9/0x270
 exit_to_user_mode_loop+0xf3/0x4d0
 do_syscall_64+0x33e/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5890d9ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff61656f78 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f5891017da0 RCX: 00007f5890d9ce59
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f5891017da0 R08: 00007f5891016218 R09: 0000000000000000
R10: 00000000003dfbd0 R11: 0000000000000246 R12: 000000000001571f
R13: 00007f589101627c R14: 00000000000154cd R15: 00007f5891016270
 </TASK>
