------------[ cut here ]------------
WARNING: CPU: 1 PID: 64 at net/xfrm/xfrm_state.c:2192 xfrm_state_fini+0x2a0/0x340 net/xfrm/xfrm_state.c:2192
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 64 Comm: kworker/u4:1 Not tainted 4.9.191+ #0
Workqueue: netns cleanup_net
 ffff8801d79af900 ffffffff81b67171 0000000000000000 ffffffff82a3b340
 00000000ffffffff 0000000000000001 0000000000000009 ffff8801d79af9e0
 ffffffff813ff0ca 0000000041b58ab3 ffffffff82e32ec5 ffffffff813feef1
Call Trace:
 [<000000002a7ced6b>] __dump_stack lib/dump_stack.c:15 [inline]
 [<000000002a7ced6b>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
 [<00000000b81ad9a0>] panic+0x1d9/0x3bd kernel/panic.c:180
 [<000000003dbf5ecf>] __warn.cold+0x2f/0x2f kernel/panic.c:546
 [<0000000076429d69>] warn_slowpath_null+0x2d/0x40 kernel/panic.c:589
 [<000000000ba9f08b>] xfrm_state_fini+0x2a0/0x340 net/xfrm/xfrm_state.c:2192
 [<00000000ea783a4b>] xfrm_net_exit+0x2e/0x40 net/xfrm/xfrm_policy.c:3122
 [<00000000d1752922>] ops_exit_list.isra.0+0xb0/0x160 net/core/net_namespace.c:136
 [<00000000ce76787e>] cleanup_net+0x3d6/0x8a0 net/core/net_namespace.c:474
 [<00000000f84b12f7>] process_one_work+0x88b/0x1600 kernel/workqueue.c:2114
 [<000000009eb88f8d>] worker_thread+0x5df/0x11d0 kernel/workqueue.c:2251
 [<00000000a7a77646>] kthread+0x278/0x310 kernel/kthread.c:211
 [<00000000ae0438bf>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:375
Kernel Offset: disabled
Rebooting in 86400 seconds..