IPVS: Creating netns size=2536 id=14
IPVS: Creating netns size=2536 id=15
IPVS: Creating netns size=2536 id=16
ip (5589) used greatest stack depth: 23744 bytes left
------------[ cut here ]------------
WARNING: CPU: 0 PID: 4085 at net/xfrm/xfrm_state.c:2167 xfrm_state_fini+0x2a0/0x340 net/xfrm/xfrm_state.c:2167
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 4085 Comm: kworker/u4:4 Not tainted 4.9.90-gdd1e37e #66
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
 ffff8801d4b67938 ffffffff81d94ee9 ffffffff83a482c0 ffff8801d4b67a10
 ffffffff83f43400 ffffffff833e1c30 0000000000000009 ffff8801d4b67a00
 ffffffff8142e651 0000000041b58ab3 ffffffff8418b7a0 ffffffff8142e495
Call Trace:
 [<ffffffff81d94ee9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d94ee9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff8142e651>] panic+0x1bc/0x3a8 kernel/panic.c:179
 [<ffffffff81132894>] __warn+0x1c4/0x1e0 kernel/panic.c:542
 [<ffffffff81132afc>] warn_slowpath_null+0x2c/0x40 kernel/panic.c:585
 [<ffffffff833e1c30>] xfrm_state_fini+0x2a0/0x340 net/xfrm/xfrm_state.c:2167
 [<ffffffff833c0c2d>] xfrm_net_exit+0x2d/0x30 net/xfrm/xfrm_policy.c:3066
 [<ffffffff82f1d8de>] ops_exit_list.isra.4+0xae/0x150 net/core/net_namespace.c:136
 [<ffffffff82f2079d>] cleanup_net+0x31d/0x610 net/core/net_namespace.c:454
 [<ffffffff8118b030>] process_one_work+0x7e0/0x1610 kernel/workqueue.c:2092
 [<ffffffff8118bf40>] worker_thread+0xe0/0x10d0 kernel/workqueue.c:2226
 [<ffffffff8119bf4d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff838b865c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..