TCP: request_sock_TCP: Possible SYN flooding on port 20028. Sending cookies.  Check SNMP counters.
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WARNING: CPU: 1 PID: 4937 at net/ipv6/ip6_fib.c:1490 fib6_del+0x9d7/0xd50 net/ipv6/ip6_fib.c:1490
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 4937 Comm: modprobe Not tainted 4.13.0-rc7+ #63
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:52
 panic+0x1e4/0x417 kernel/panic.c:180
 __warn+0x1c4/0x1d9 kernel/panic.c:541
 report_bug+0x211/0x2d0 lib/bug.c:183
 fixup_bug+0x40/0x90 arch/x86/kernel/traps.c:190
 do_trap_no_signal arch/x86/kernel/traps.c:224 [inline]
 do_trap+0x260/0x390 arch/x86/kernel/traps.c:273
 do_error_trap+0x120/0x390 arch/x86/kernel/traps.c:310
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:323
 invalid_op+0x1e/0x30 arch/x86/entry/entry_64.S:846
RIP: 0010:fib6_del+0x9d7/0xd50 net/ipv6/ip6_fib.c:1490
RSP: 0000:ffff8801db307358 EFLAGS: 00010206
RAX: ffff8801cc46a100 RBX: ffff8801c2c50700 RCX: 0000000000000000
RDX: 0000000000000100 RSI: ffff8801ce7e1830 RDI: ffff8801c2c50764
RBP: ffff8801db307470 R08: ffffffff86df1148 R09: 0000000000000002
R10: ffff8801db307338 R11: 1ffff1003988d67b R12: dffffc0000000000
R13: ffff8801db3074d0 R14: ffff88019c14c200 R15: 1ffff1003b660e75
 __ip6_del_rt+0xc7/0x120 net/ipv6/route.c:2146
 ip6_del_rt+0x132/0x1a0 net/ipv6/route.c:2159
 ip6_link_failure+0x1a6/0x580 net/ipv6/route.c:1362
 dst_link_failure include/net/dst.h:454 [inline]
 ndisc_error_report+0xae/0x180 net/ipv6/ndisc.c:682
 neigh_invalidate+0x225/0x530 net/core/neighbour.c:883
 neigh_timer_handler+0x883/0xca0 net/core/neighbour.c:969
 call_timer_fn+0x233/0x830 kernel/time/timer.c:1281
 expire_timers kernel/time/timer.c:1320 [inline]
 __run_timers+0x7fd/0xb90 kernel/time/timer.c:1620
 run_timer_softirq+0x4c/0xb0 kernel/time/timer.c:1646
 __do_softirq+0x2f5/0xba3 kernel/softirq.c:284
 invoke_softirq kernel/softirq.c:364 [inline]
 irq_exit+0x1cc/0x200 kernel/softirq.c:405
 exiting_irq arch/x86/include/asm/apic.h:638 [inline]
 smp_trace_apic_timer_interrupt+0x139/0x6a0 arch/x86/kernel/apic/apic.c:1065
 trace_apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:702
RIP: 0033:0x7f58009a2935
RSP: 002b:00007fff0fbcb2f8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff10
RAX: 0000562e53d4ca80 RBX: 0000562e53d4ca80 RCX: 0000000000000203
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000562e53d4ca80
RBP: 0000000000018db0 R08: 0000000000001018 R09: 0000000000000000
R10: 0000000000000000 R11: 00007f5800a77a50 R12: 0000562e53d52250
R13: 0000000000001018 R14: 00007f5800ca8e40 R15: 0000562e53d4ca70
 </IRQ>
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..