======================================
| [ 1112.127340][    C1] TCP: request_sock_TCP: Possible SYN flooding on port 127.0.0.1:23456. Sending cookies.
| [ 1112.658685][    C3] TCP: request_sock_TCP: Possible SYN flooding on port 127.0.0.1:23456. Sending cookies.
| [ 1113.932619][    C3] Oops: general protection fault, probably for non-canonical address 0xdffffc000000000e: 0000 [#1] PREEMPT SMP KASAN NOPTI
| [ 1113.933042][    C3] KASAN: null-ptr-deref in range [0x0000000000000070-0x0000000000000077]
[ 1113.933436][    C3] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 1113.933735][ C3] RIP: 0010:__inet_csk_reqsk_queue_drop (./include/linux/list.h:958 ./include/net/sock.h:744 ./include/net/sock.h:749 net/ipv4/inet_connection_sock.c:1042 net/ipv4/inet_connection_sock.c:1058) 
[ 1113.933913][ C3] Code: 00 00 00 00 00 fc ff df 41 57 4c 8d 7e 70 41 56 41 55 41 89 d5 4c 89 fa 41 54 48 c1 ea 03 55 48 89 f5 53 48 89 fb 48 83 ec 08 <80> 3c 02 00 0f 85 6c 05 00 00 45 31 e4 48 83 7d 70 00 0f 84 0f 01
All code
========
   0:	00 00                	add    %al,(%rax)
   2:	00 00                	add    %al,(%rax)
   4:	00 fc                	add    %bh,%ah
   6:	ff                   	(bad)
   7:	df 41 57             	filds  0x57(%rcx)
   a:	4c 8d 7e 70          	lea    0x70(%rsi),%r15
   e:	41 56                	push   %r14
  10:	41 55                	push   %r13
  12:	41 89 d5             	mov    %edx,%r13d
  15:	4c 89 fa             	mov    %r15,%rdx
  18:	41 54                	push   %r12
  1a:	48 c1 ea 03          	shr    $0x3,%rdx
  1e:	55                   	push   %rbp
  1f:	48 89 f5             	mov    %rsi,%rbp
  22:	53                   	push   %rbx
  23:	48 89 fb             	mov    %rdi,%rbx
  26:	48 83 ec 08          	sub    $0x8,%rsp
  2a:*	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)		<-- trapping instruction
  2e:	0f 85 6c 05 00 00    	jne    0x5a0
  34:	45 31 e4             	xor    %r12d,%r12d
  37:	48 83 7d 70 00       	cmpq   $0x0,0x70(%rbp)
  3c:	0f                   	.byte 0xf
  3d:	84 0f                	test   %cl,(%rdi)
  3f:	01                   	.byte 0x1

Code starting with the faulting instruction
===========================================
   0:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   4:	0f 85 6c 05 00 00    	jne    0x576
   a:	45 31 e4             	xor    %r12d,%r12d
   d:	48 83 7d 70 00       	cmpq   $0x0,0x70(%rbp)
  12:	0f                   	.byte 0xf
  13:	84 0f                	test   %cl,(%rdi)
  15:	01                   	.byte 0x1
[ 1113.934382][    C3] RSP: 0018:ffffc90000298c28 EFLAGS: 00010296
[ 1113.934556][    C3] RAX: dffffc0000000000 RBX: ffff888009db8d40 RCX: 1ffff110003765a7
[ 1113.934741][    C3] RDX: 000000000000000e RSI: 0000000000000000 RDI: ffff888009db8d40
[ 1113.934932][    C3] RBP: 0000000000000000 R08: ffffffffb2d3fedf R09: fffffbfff6a2e811
[ 1113.935136][    C3] R10: ffffffffb517408f R11: 0000000000000001 R12: 0000000000000000
[ 1113.935327][    C3] R13: 0000000000000001 R14: ffff888003b9a278 R15: 0000000000000070
[ 1113.935519][    C3] FS:  0000000000000000(0000) GS:ffff888036180000(0000) knlGS:0000000000000000
[ 1113.935742][    C3] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1113.935904][    C3] CR2: 00007f94ca8fa020 CR3: 00000000116b4002 CR4: 0000000000772ef0
[ 1113.936096][    C3] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1113.936302][    C3] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 1113.936514][    C3] PKRU: 55555554
[ 1113.936620][    C3] Call Trace:
[ 1113.936728][    C3]  <IRQ>
[ 1113.936800][ C3] ? die_addr (arch/x86/kernel/dumpstack.c:421 arch/x86/kernel/dumpstack.c:460) 
[ 1113.936916][ C3] ? exc_general_protection (arch/x86/kernel/traps.c:751 arch/x86/kernel/traps.c:693) 
[ 1113.937050][ C3] ? asm_exc_general_protection (./arch/x86/include/asm/idtentry.h:617) 
[ 1113.937181][ C3] ? reuseport_migrate_sock (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/sock_reuseport.c:674) 
[ 1113.937310][ C3] ? __inet_csk_reqsk_queue_drop (./include/linux/list.h:958 ./include/net/sock.h:744 ./include/net/sock.h:749 net/ipv4/inet_connection_sock.c:1042 net/ipv4/inet_connection_sock.c:1058) 
[ 1113.937467][ C3] ? lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5827) 
[ 1113.937598][ C3] reqsk_timer_handler (./include/net/request_sock.h:148 net/ipv4/inet_connection_sock.c:1194) 
[ 1113.937726][ C3] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5790) 
[ 1113.937857][ C3] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 52)) 
[ 1113.937991][ C3] ? __pfx_reqsk_timer_handler (net/ipv4/inet_connection_sock.c:1085) 
[ 1113.938117][ C3] ? call_timer_fn (kernel/time/timer.c:1791) 
[ 1113.938243][ C3] ? lock_acquire (kernel/locking/lockdep.c:5798) 
[ 1113.938370][ C3] ? __pfx_reqsk_timer_handler (net/ipv4/inet_connection_sock.c:1085) 
[ 1113.938495][ C3] call_timer_fn (kernel/time/timer.c:1794) 
[ 1113.938624][ C3] ? call_timer_fn (./include/linux/lockdep.h:31 kernel/time/timer.c:1784) 
[ 1113.938751][ C3] ? call_timer_fn (./include/linux/lockdep.h:31 kernel/time/timer.c:1784) 
[ 1113.938879][ C3] ? __pfx_call_timer_fn (kernel/time/timer.c:1771) 
[ 1113.939008][ C3] ? mark_lock (kernel/locking/lockdep.c:4703 (discriminator 3)) 
[ 1113.939111][ C3] __run_timers (kernel/time/timer.c:1846 kernel/time/timer.c:2419) 
[ 1113.939246][ C3] ? __pfx_reqsk_timer_handler (net/ipv4/inet_connection_sock.c:1085) 
[ 1113.939373][ C3] ? __pfx___run_timers (kernel/time/timer.c:2390) 
[ 1113.939495][ C3] ? do_raw_spin_lock (./arch/x86/include/asm/atomic.h:107 ./include/linux/atomic/atomic-arch-fallback.h:2170 ./include/linux/atomic/atomic-instrumented.h:1302 ./include/asm-generic/qspinlock.h:111 kernel/locking/spinlock_debug.c:116) 
[ 1113.939625][ C3] ? __pfx_do_raw_spin_lock (kernel/locking/spinlock_debug.c:114) 
[ 1113.939749][ C3] ? lock_acquire (kernel/locking/lockdep.c:5798) 
[ 1113.939877][ C3] ? run_timer_softirq (kernel/time/timer.c:2430 kernel/time/timer.c:2423 kernel/time/timer.c:2439 kernel/time/timer.c:2447) 
[ 1113.940007][ C3] run_timer_softirq (kernel/time/timer.c:2431 kernel/time/timer.c:2423 kernel/time/timer.c:2439 kernel/time/timer.c:2447) 
[ 1113.940137][ C3] handle_softirqs (kernel/softirq.c:554) 
[ 1113.940267][ C3] irq_exit_rcu (kernel/softirq.c:589 kernel/softirq.c:428 kernel/softirq.c:637 kernel/softirq.c:649) 
[ 1113.940360][ C3] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1037 arch/x86/kernel/apic/apic.c:1037) 
[ 1113.940487][    C3]  </IRQ>
[ 1113.940552][    C3]  <TASK>
[ 1113.940617][ C3] asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) 
[ 1113.940777][ C3] RIP: 0010:default_idle (./arch/x86/include/asm/irqflags.h:37 ./arch/x86/include/asm/irqflags.h:92 arch/x86/kernel/process.c:743) 
[ 1113.940914][ C3] Code: 4c 01 c7 4c 29 c2 e9 72 ff ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 23 ba 3f 00 fb f4 <fa> c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90
All code
========
   0:	4c 01 c7             	add    %r8,%rdi
   3:	4c 29 c2             	sub    %r8,%rdx
   6:	e9 72 ff ff ff       	jmp    0xffffffffffffff7d
   b:	90                   	nop
   c:	90                   	nop
   d:	90                   	nop
   e:	90                   	nop
   f:	90                   	nop
  10:	90                   	nop
  11:	90                   	nop
  12:	90                   	nop
  13:	90                   	nop
  14:	90                   	nop
  15:	90                   	nop
  16:	90                   	nop
  17:	90                   	nop
  18:	90                   	nop
  19:	90                   	nop
  1a:	90                   	nop
  1b:	f3 0f 1e fa          	endbr64
  1f:	66 90                	xchg   %ax,%ax
  21:	0f 00 2d 23 ba 3f 00 	verw   0x3fba23(%rip)        # 0x3fba4b
  28:	fb                   	sti
  29:	f4                   	hlt
  2a:*	fa                   	cli		<-- trapping instruction
  2b:	c3                   	ret
  2c:	cc                   	int3
  2d:	cc                   	int3
  2e:	cc                   	int3
  2f:	cc                   	int3
  30:	66 66 2e 0f 1f 84 00 	data16 cs nopw 0x0(%rax,%rax,1)
  37:	00 00 00 00 
  3b:	90                   	nop
  3c:	90                   	nop
  3d:	90                   	nop
  3e:	90                   	nop
  3f:	90                   	nop

Code starting with the faulting instruction
===========================================
   0:	fa                   	cli
   1:	c3                   	ret
   2:	cc                   	int3
   3:	cc                   	int3
   4:	cc                   	int3
   5:	cc                   	int3
   6:	66 66 2e 0f 1f 84 00 	data16 cs nopw 0x0(%rax,%rax,1)
   d:	00 00 00 00 
  11:	90                   	nop
  12:	90                   	nop
  13:	90                   	nop
  14:	90                   	nop
  15:	90                   	nop
[ 1113.941373][    C3] RSP: 0018:ffffc9000017fdf8 EFLAGS: 00000242
[ 1113.941535][    C3] RAX: 0000000001e6e65d RBX: 1ffff9200002ffc1 RCX: ffffffffb34658f5
[ 1113.941728][    C3] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffb0cb2564
[ 1113.941928][    C3] RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1006c370e2
[ 1113.942118][    C3] R10: ffff8880361b8713 R11: ffff8880361bdd40 R12: 0000000000000000
[ 1113.942306][    C3] R13: ffff888001bb2300 R14: dffffc0000000000 R15: 0000000000000000
[ 1113.942502][ C3] ? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:147) 
[ 1113.942635][ C3] ? cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 1113.942763][ C3] default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) 
[ 1113.942890][ C3] cpuidle_idle_call (kernel/sched/idle.c:186) 
[ 1113.943021][ C3] ? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168) 
[ 1113.943150][ C3] ? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:59) 
[ 1113.943284][ C3] do_idle (kernel/sched/idle.c:326) 
[ 1113.943380][ C3] cpu_startup_entry (kernel/sched/idle.c:423 (discriminator 1)) 
[ 1113.943510][ C3] start_secondary (arch/x86/kernel/smpboot.c:202 arch/x86/kernel/smpboot.c:282) 
[ 1113.943636][ C3] ? __pfx_start_secondary (arch/x86/kernel/smpboot.c:232) 


Finger prints:
__inet_csk_reqsk_queue_drop:reqsk_timer_handler:call_timer_fn:__run_timers:run_timer_softirq