------------[ cut here ]------------
WARNING: CPU: 0 PID: 8701 at net/ipv4/af_inet.c:167 inet_sock_destruct+0x598/0x760 net/ipv4/af_inet.c:167()
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 8701 Comm: kworker/0:0 Not tainted 4.4.150-g5541782 #83
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: sock_diag_events sock_diag_broadcast_destroy_work
 0000000000000000 c17b2413734e16ce ffff88009402fa30 ffffffff81e14e2d
 ffffffff83a44e40 ffff8800b59db000 ffffffff83f13300 0000000000000009
 00000000000000a7 ffff88009402faf0 ffffffff8140d3c4 0000000041b58ab3
Call Trace:
 [<ffffffff81e14e2d>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81e14e2d>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff8140d3c4>] panic+0x19e/0x38d kernel/panic.c:112
 [<ffffffff8140d5e8>] warn_slowpath_common.cold.6+0x20/0x20 kernel/panic.c:455
 [<ffffffff81133069>] warn_slowpath_null+0x29/0x30 kernel/panic.c:492
 [<ffffffff833043b8>] inet_sock_destruct+0x598/0x760 net/ipv4/af_inet.c:167
 [<ffffffff835a85fe>] l2tp_tunnel_destruct+0x33e/0x590 net/l2tp/l2tp_core.c:1235
 [<ffffffff82f36e3c>] sk_destruct+0x4c/0x4c0 net/core/sock.c:1447
 [<ffffffff82fd3f2a>] sock_diag_broadcast_destroy_work+0x21a/0x390 net/core/sock_diag.c:153
 [<ffffffff81184eff>] process_one_work+0x7df/0x1600 kernel/workqueue.c:2064
 [<ffffffff81185df9>] worker_thread+0xd9/0xfc0 kernel/workqueue.c:2196
 [<ffffffff81193908>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff838cb4d5>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:510
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..