------------[ cut here ]------------
WARNING: CPU: 1 PID: 2200 at net/xfrm/xfrm_state.c:2148 xfrm_state_fini+0x297/0x330 net/xfrm/xfrm_state.c:2148()
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 2200 Comm: kworker/u4:6 Not tainted 4.4.174+ #4
Workqueue: netns cleanup_net
 0000000000000000 634e895e5682ec21 ffff8800b8737910 ffffffff81aad1a1
 0000000000000000 ffffffff82835ee0 ffffffff82a9bc00 0000000000000864
 ffffffff82567fb7 ffff8800b87379f0 ffffffff813a48c2 0000000041b58ab3
Call Trace:
 [<ffffffff81aad1a1>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81aad1a1>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
 [<ffffffff813a48c2>] panic+0x1b9/0x37b kernel/panic.c:112
 [<ffffffff813a4ab9>] warn_slowpath_common kernel/panic.c:455 [inline]
 [<ffffffff813a4ab9>] warn_slowpath_common.cold+0x20/0x20 kernel/panic.c:435
 [<ffffffff810d3aaa>] warn_slowpath_null+0x2a/0x30 kernel/panic.c:492
 [<ffffffff82567fb7>] xfrm_state_fini+0x297/0x330 net/xfrm/xfrm_state.c:2148
 [<ffffffff8254a67e>] xfrm_net_exit+0x2e/0x40 net/xfrm/xfrm_policy.c:3044
 [<ffffffff82217d90>] ops_exit_list.isra.0+0xb0/0x160 net/core/net_namespace.c:134
 [<ffffffff8221ac16>] cleanup_net+0x3d6/0x860 net/core/net_namespace.c:452
 [<ffffffff81122c25>] process_one_work+0x825/0x1720 kernel/workqueue.c:2064
 [<ffffffff81124004>] worker_thread+0x4e4/0xf50 kernel/workqueue.c:2196
 [<ffffffff811342c3>] kthread+0x273/0x310 kernel/kthread.c:211
 [<ffffffff82718fc5>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:537
Kernel Offset: disabled
Rebooting in 86400 seconds..