TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies.  Check SNMP counters.
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BUG: KASAN: null-ptr-deref in atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
BUG: KASAN: null-ptr-deref in refcount_sub_and_test_checked+0x9d/0x310 lib/refcount.c:179
Read of size 4 at addr 000000000000002e by task udevd/5753

CPU: 0 PID: 5753 Comm: udevd Not tainted 4.19.0-rc6+ #245
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113
 kasan_report_error mm/kasan/report.c:352 [inline]
 kasan_report.cold.9+0x6d/0x309 mm/kasan/report.c:412
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
 kasan_check_read+0x11/0x20 mm/kasan/kasan.c:272
 atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
 refcount_sub_and_test_checked+0x9d/0x310 lib/refcount.c:179
 refcount_dec_and_test_checked+0x1a/0x20 lib/refcount.c:212
 ip_fib_metrics_put include/net/ip.h:428 [inline]
 fib6_info_destroy_rcu+0x2ef/0x3e0 net/ipv6/ip6_fib.c:204
 __rcu_reclaim kernel/rcu/rcu.h:236 [inline]
 rcu_do_batch kernel/rcu/tree.c:2576 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2880 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2847 [inline]
 rcu_process_callbacks+0xf23/0x2670 kernel/rcu/tree.c:2864
 __do_softirq+0x30b/0xad8 kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:372 [inline]
 irq_exit+0x17f/0x1c0 kernel/softirq.c:412
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x1cb/0x760 arch/x86/kernel/apic/apic.c:1056
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:864
 </IRQ>
RIP: 0010:unwind_next_frame.part.7+0x10/0x9e0 arch/x86/kernel/unwind_frame.c:282
Code: e8 75 d4 8b 00 e9 4e ff ff ff 4c 89 ff e8 08 d4 8b 00 eb 87 e8 41 79 12 00 90 48 ba 00 00 00 00 00 fc ff df 55 48 89 e5 41 57 <41> 56 4c 8d 7f 50 41 55 41 54 4c 8d a5 38 ff ff ff 49 c1 ec 03 53
RSP: 0018:ffff8801d8d8ea68 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: ffff8801d8d8ea98 RCX: 000000000000000a
RDX: dffffc0000000000 RSI: ffffffff87c0008d RDI: ffff8801d8d8ea98
RBP: ffff8801d8d8ea70 R08: ffff8801d8d8ead0 R09: ffff8801bc5f60c0
R10: ffffed003b1b1d5d R11: ffff8801d8d8eaef R12: 0000000000000000
R13: 0000000000000000 R14: ffff8801bc5f60c0 R15: ffff8801d22945ef
 unwind_next_frame+0x3e/0x50 arch/x86/kernel/unwind_frame.c:287
 __save_stack_trace+0x7d/0xf0 arch/x86/kernel/stacktrace.c:44
 save_stack_trace+0x1a/0x20 arch/x86/kernel/stacktrace.c:60
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490
 kmem_cache_alloc+0x12e/0x730 mm/slab.c:3554
 vm_area_dup+0x7a/0x230 kernel/fork.c:323
 dup_mmap kernel/fork.c:484 [inline]
 dup_mm kernel/fork.c:1274 [inline]
 copy_mm kernel/fork.c:1329 [inline]
 copy_process+0x42a0/0x8780 kernel/fork.c:1869
 _do_fork+0x1cb/0x11d0 kernel/fork.c:2166
 __do_sys_clone kernel/fork.c:2273 [inline]
 __se_sys_clone kernel/fork.c:2267 [inline]
 __x64_sys_clone+0xbf/0x150 kernel/fork.c:2267
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f9d81052f46
Code: f7 d8 64 89 04 25 d4 02 00 00 64 4c 8b 14 25 10 00 00 00 31 d2 49 81 c2 d0 02 00 00 31 f6 bf 11 00 20 01 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 31 01 00 00 85 c0 41 89 c4 0f 85 3b 01 00
RSP: 002b:00007ffdf8745410 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffdf8745410 RCX: 00007f9d81052f46
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007ffdf8745470 R08: 0000000000001679 R09: 0000000000001679
R10: 00007f9d8196fa70 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffdf8745430 R14: 0000000000000005 R15: 0000000000000005
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