======================================
| 0
| xx__-> [   15.605188][  T231] ------------[ cut here ]------------
| [   15.605804][  T231] WARNING: CPU: 3 PID: 231 at ./include/net/sch_generic.h:843 fq_dequeue_skb (./include/net/sch_generic.h:843 ./include/net/sch_generic.h:889 ./include/net/sch_generic.h:901 net/sched/sch_fq.c:503)
| [   15.606390][  T231] Modules linked in:
[   15.607404][  T231] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   15.607811][  T231] RIP: 0010:fq_dequeue_skb (./include/net/sch_generic.h:843 ./include/net/sch_generic.h:889 ./include/net/sch_generic.h:901 net/sched/sch_fq.c:503)
[   15.608165][  T231] Code: d0 7c 08 84 d2 0f 85 8d 00 00 00 8b 43 28 48 01 85 a0 01 00 00 4c 01 b5 a8 01 00 00 48 83 c4 08 5b 5d 41 5c 41 5d 41 5e c3 90 <0f> 0b 90 eb b2 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03
All code
========
   0:	d0 7c 08 84          	sarb   $1,-0x7c(%rax,%rcx,1)
   4:	d2 0f                	rorb   %cl,(%rdi)
   6:	85 8d 00 00 00 8b    	test   %ecx,-0x75000000(%rbp)
   c:	43 28 48 01          	rex.XB sub %cl,0x1(%r8)
  10:	85 a0 01 00 00 4c    	test   %esp,0x4c000001(%rax)
  16:	01 b5 a8 01 00 00    	add    %esi,0x1a8(%rbp)
  1c:	48 83 c4 08          	add    $0x8,%rsp
  20:	5b                   	pop    %rbx
  21:	5d                   	pop    %rbp
  22:	41 5c                	pop    %r12
  24:	41 5d                	pop    %r13
  26:	41 5e                	pop    %r14
  28:	c3                   	ret
  29:	90                   	nop
  2a:*	0f 0b                	ud2		<-- trapping instruction
  2c:	90                   	nop
  2d:	eb b2                	jmp    0xffffffffffffffe1
  2f:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  36:	fc ff df 
  39:	48 89 da             	mov    %rbx,%rdx
  3c:	48 c1 ea 03          	shr    $0x3,%rdx

Code starting with the faulting instruction
===========================================
   0:	0f 0b                	ud2
   2:	90                   	nop
   3:	eb b2                	jmp    0xffffffffffffffb7
   5:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
   c:	fc ff df 
   f:	48 89 da             	mov    %rbx,%rdx
  12:	48 c1 ea 03          	shr    $0x3,%rdx
[   15.609362][  T231] RSP: 0018:ffffc90000ae70f8 EFLAGS: 00010202
[   15.609777][  T231] RAX: 0000000000000007 RBX: ffff88800b738118 RCX: 0000000000000001
[   15.610279][  T231] RDX: 0000000000000000 RSI: ffff888004a9d348 RDI: ffff888004a1da06
[   15.610782][  T231] RBP: ffff888004a9d000 R08: 0000000000000000 R09: ffff888004a9d040
[   15.611299][  T231] R10: ffffffffae60df57 R11: ffff888004a9d384 R12: ffff888004a1da00
[   15.611799][  T231] R13: ffff88800b738140 R14: 0000000000000002 R15: ffff888004a9d000
[   15.612311][  T231] FS:  000000002ee733c0(0000) GS:ffff88808739a000(0000) knlGS:0000000000000000
[   15.612884][  T231] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   15.613322][  T231] CR2: 00007ffb416d9000 CR3: 000000000bffa002 CR4: 0000000000772ef0
[   15.613825][  T231] PKRU: 55555554
[   15.614253][  T231] Call Trace:
[   15.614521][  T231]  <TASK>
[   15.614771][  T231]  ? lockdep_unlock (kernel/locking/lockdep.c:159)
[   15.615118][  T231]  fq_dequeue (net/sched/sch_fq.c:671)
[   15.615459][  T231]  ? __lock_acquire (kernel/locking/lockdep.c:5237)
[   15.615804][  T231]  dequeue_skb (net/sched/sch_generic.c:297)
[   15.616141][  T231]  __qdisc_run (net/sched/sch_generic.c:403 net/sched/sch_generic.c:420)
[   15.616480][  T231]  ? kvm_clock_get_cycles (./arch/x86/include/asm/preempt.h:95 arch/x86/kernel/kvmclock.c:80 arch/x86/kernel/kvmclock.c:86)
[   15.616823][  T231]  ? sch_direct_xmit (net/sched/sch_generic.c:416)
[   15.617160][  T231]  ? fq_enqueue (net/sched/sch_fq.c:580)
[   15.617495][  T231]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   15.617824][  T231]  __dev_xmit_skb (./include/net/sch_generic.h:223 ./include/net/pkt_sched.h:121 ./include/net/pkt_sched.h:117 net/core/dev.c:4254)
[   15.618163][  T231]  ? dev_get_stats (net/core/dev.c:4143)
[   15.618507][  T231]  ? rcu_is_watching (./include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[   15.618847][  T231]  ? lock_acquire (./include/trace/events/lock.h:24 kernel/locking/lockdep.c:5831)
[   15.619178][  T231]  __dev_queue_xmit (net/core/dev.c:4786)
[   15.619530][  T231]  ? netdev_core_pick_tx (net/core/dev.c:4728)
[   15.619867][  T231]  ? find_held_lock (kernel/locking/lockdep.c:5350)
[   15.620202][  T231]  ? neigh_connected_output (./include/linux/seqlock.h:74 ./include/linux/seqlock.h:836 net/core/neighbour.c:1617)
[   15.620538][  T231]  ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4472)
[   15.620872][  T231]  ? neigh_connected_output (./include/linux/seqlock.h:74 ./include/linux/seqlock.h:836 net/core/neighbour.c:1617)
[   15.621206][  T231]  ip_finish_output2 (./include/net/neighbour.h:556 net/ipv4/ip_output.c:237)
[   15.621558][  T231]  ? ip_skb_dst_mtu (./include/linux/rcupdate.h:341 ./include/linux/rcupdate.h:897 ./include/net/ip.h:504 ./include/net/ip.h:518)
[   15.621887][  T231]  ? ip_fragment.constprop.0 (net/ipv4/ip_output.c:201)
[   15.622213][  T231]  ? __ip_finish_output (net/ipv4/ip_output.c:258 net/ipv4/ip_output.c:310)
[   15.622547][  T231]  ip_output (./include/linux/netfilter.h:414 net/ipv4/ip_output.c:438)
[   15.622799][  T231]  __ip_queue_xmit (./include/net/dst.h:464 net/ipv4/ip_output.c:131 net/ipv4/ip_output.c:534)
[   15.623121][  T231]  ? __skb_clone (./arch/x86/include/asm/atomic.h:53 (discriminator 4) ./include/linux/atomic/atomic-arch-fallback.h:992 (discriminator 4) ./include/linux/atomic/atomic-instrumented.h:436 (discriminator 4) net/core/skbuff.c:1585 (discriminator 4))
[   15.623454][  T231]  __tcp_transmit_skb (net/ipv4/tcp_output.c:1628)
[   15.623792][  T231]  ? get_page (./arch/x86/include/asm/atomic.h:53 ./include/linux/atomic/atomic-arch-fallback.h:992 ./include/linux/atomic/atomic-instrumented.h:436 ./include/linux/page_ref.h:153 ./include/linux/page_ref.h:160 ./include/linux/mm.h:1387 ./include/linux/mm.h:1397)
[   15.624037][  T231]  ? __tcp_select_window (net/ipv4/tcp_output.c:1449)
[   15.624400][  T231]  tcp_write_xmit (net/ipv4/tcp_output.c:2999)
[   15.624731][  T231]  ? __alloc_skb (./arch/x86/include/asm/atomic.h:28 ./include/linux/atomic/atomic-arch-fallback.h:503 ./include/linux/atomic/atomic-instrumented.h:68 ./include/linux/refcount.h:134 net/core/skbuff.c:698)
[   15.625058][  T231]  ? tcp_retrans_try_collapse (net/ipv4/tcp_output.c:2903)
[   15.625391][  T231]  ? trace_tcp_ao_handshake_failure (./include/linux/cpumask.h:135 ./include/linux/cpumask.h:142 ./include/linux/cpumask.h:646 ./include/linux/cpumask.h:1205 ./include/trace/events/tcp.h:689 ./include/trace/events/tcp.h:689)
[   15.625809][  T231]  ? __sk_mem_schedule (net/core/sock.c:3410)
[   15.626139][  T231]  tcp_sendmsg_locked (net/ipv4/tcp.c:1355)
[   15.626505][  T231]  ? tcp_sendmsg_fastopen (net/ipv4/tcp.c:1078)
[   15.626847][  T231]  ? find_held_lock (kernel/locking/lockdep.c:5350)
[   15.627173][  T231]  ? __local_bh_enable_ip (./arch/x86/include/asm/irqflags.h:42 ./arch/x86/include/asm/irqflags.h:119 kernel/softirq.c:455)
[   15.627513][  T231]  tcp_sendmsg (net/ipv4/tcp.c:1413)
[   15.627771][  T231]  sock_write_iter (net/socket.c:727 net/socket.c:742 net/socket.c:1195)
[   15.628110][  T231]  ? ____sys_recvmsg (net/socket.c:1176)
[   15.628446][  T231]  ? sk_setsockopt (net/core/sock.c:1161 net/core/sock.c:1674)
[   15.628797][  T231]  ? __lock_acquire (kernel/locking/lockdep.c:5237)
[   15.629124][  T231]  vfs_write (fs/read_write.c:594 fs/read_write.c:686)
[   15.629381][  T231]  ? find_held_lock (kernel/locking/lockdep.c:5350)
[   15.629715][  T231]  ? kernel_write (fs/read_write.c:667)
[   15.630047][  T231]  ? __fget_files (./include/linux/rcupdate.h:341 ./include/linux/rcupdate.h:897 fs/file.c:1072)
[   15.630400][  T231]  ksys_write (fs/read_write.c:738)
[   15.630644][  T231]  ? fput (./arch/x86/include/asm/preempt.h:104 ./include/linux/preempt.h:470 ./include/linux/file_ref.h:150 fs/file_table.c:544)
[   15.630888][  T231]  ? __ia32_sys_read (fs/read_write.c:728)
[   15.631218][  T231]  do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)
[   15.631551][  T231]  entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[   15.631956][  T231] RIP: 0033:0x49002f
[   15.632217][  T231] Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 89 7a 04 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 dc 7a 04 00 48
All code
========
   0:	89 54 24 18          	mov    %edx,0x18(%rsp)
   4:	48 89 74 24 10       	mov    %rsi,0x10(%rsp)
   9:	89 7c 24 08          	mov    %edi,0x8(%rsp)
   d:	e8 89 7a 04 00       	call   0x47a9b
  12:	48 8b 54 24 18       	mov    0x18(%rsp),%rdx
  17:	48 8b 74 24 10       	mov    0x10(%rsp),%rsi
  1c:	41 89 c0             	mov    %eax,%r8d
  1f:	8b 7c 24 08          	mov    0x8(%rsp),%edi
  23:	b8 01 00 00 00       	mov    $0x1,%eax
  28:	0f 05                	syscall
  2a:*	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax		<-- trapping instruction
  30:	77 31                	ja     0x63
  32:	44 89 c7             	mov    %r8d,%edi
  35:	48 89 44 24 08       	mov    %rax,0x8(%rsp)
  3a:	e8 dc 7a 04 00       	call   0x47b1b
  3f:	48                   	rex.W

Code starting with the faulting instruction
===========================================
   0:	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax
   6:	77 31                	ja     0x39
   8:	44 89 c7             	mov    %r8d,%edi
   b:	48 89 44 24 08       	mov    %rax,0x8(%rsp)
  10:	e8 dc 7a 04 00       	call   0x47af1
  15:	48                   	rex.W
[   15.633389][  T231] RSP: 002b:00007ffda9978e50 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
[   15.633880][  T231] RAX: ffffffffffffffda RBX: 00007ffda9979440 RCX: 000000000049002f
[   15.634388][  T231] RDX: 0000000000009c40 RSI: 000000002ee876c0 RDI: 000000000000000a
[   15.634884][  T231] RBP: 00007ffda9978ed0 R08: 0000000000000000 R09: 00000000000009d3
[   15.635377][  T231] R10: 0000000000000010 R11: 0000000000000293 R12: 00007ffda99793b8


Finger prints:
fq_dequeue_skb:fq_dequeue:dequeue_skb:__qdisc_run:__dev_xmit_skb