IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
IPVS: ftp: loaded support on port[0] = 21
WARNING: CPU: 0 PID: 20 at net/kcm/kcmsock.c:2023 kcm_exit_net+0xf8/0x100 net/kcm/kcmsock.c:2023
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 20 Comm: kworker/u4:1 Not tainted 4.17.0-rc5+ #103
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:113
 panic+0x39d/0x940 kernel/panic.c:184
 __warn+0x40f/0x580 kernel/panic.c:536
 report_bug+0x72a/0x880 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:179 [inline]
 do_error_trap+0x1c1/0x620 arch/x86/kernel/traps.c:298
 do_invalid_op+0x46/0x50 arch/x86/kernel/traps.c:317
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:992
RIP: 0010:kcm_exit_net+0xf8/0x100 net/kcm/kcmsock.c:2023
RSP: 0018:ffff8801d897fb90 EFLAGS: 00010293
RAX: ffffffff89221898 RBX: 0000000000000000 RCX: ffff8801d8803a80
RDX: 0000000000000000 RSI: aaaaaaaaaaaab000 RDI: ffffea0000000000
RBP: ffff8801d897fbc0 R08: 0000000001080000 R09: 0000000000000002
R10: 0000000000000000 R11: 0000000000000000 R12: ffff880194a55680
R13: 0000000000000000 R14: ffff8801942bd3b0 R15: 0000000000000000
 ops_exit_list net/core/net_namespace.c:152 [inline]
 cleanup_net+0xa4e/0x1670 net/core/net_namespace.c:523
 process_one_work+0x12c6/0x1f60 kernel/workqueue.c:2145
 worker_thread+0x113c/0x24f0 kernel/workqueue.c:2279
 kthread+0x4e3/0x6d0 kernel/kthread.c:241
 ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:412
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..