======================================
| [ 21.346517][ T663] #0: ffffffff9176f640 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit (./include/linux/bottom_half.h:20 ./include/linux/rcupdate.h:901 net/core/dev.c:4555) 
| [ 21.346863][ T663] #1: ffff88800a802258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+...}-{3:3}, at: __dev_xmit_skb (./include/net/sch_generic.h:197 ./include/net/sch_generic.h:194 net/core/dev.c:4006) 
| [   21.347513][  T663]
| [   21.347513][  T663] stack backtrace:
[   21.347738][  T663] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   21.347740][  T663] Call Trace:
[   21.347742][  T663]  <TASK>
[ 21.347745][ T663] dump_stack_lvl (lib/dump_stack.c:123) 
[ 21.347755][ T663] lockdep_rcu_suspicious (kernel/locking/lockdep.c:6848) 
[ 21.347768][ T663] dev_hard_start_xmit (./include/net/net_namespace.h:418 ./include/linux/netdevice.h:2695 net/core/dev.c:2466 net/core/dev.c:3772 net/core/dev.c:3793) 
[ 21.347780][ T663] sch_direct_xmit (net/sched/sch_generic.c:343) 
[ 21.347789][ T663] ? tun_select_queue (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 drivers/net/tun.c:545) 
[ 21.347796][ T663] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5816) 
[ 21.347802][ T663] ? __pfx_sch_direct_xmit (net/sched/sch_generic.c:318) 
[ 21.347805][ T663] ? do_raw_spin_trylock (./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:97 kernel/locking/spinlock_debug.c:123) 
[ 21.347813][ T663] ? lock_acquire (kernel/locking/lockdep.c:5824) 
[ 21.347815][ T663] ? __dev_xmit_skb (./include/net/sch_generic.h:197 ./include/net/sch_generic.h:194 net/core/dev.c:4006) 
[ 21.347825][ T663] __dev_xmit_skb (net/core/dev.c:4019) 
[ 21.347829][ T663] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5816) 
[ 21.347836][ T663] ? __pfx___dev_xmit_skb (net/core/dev.c:3994) 
[ 21.347844][ T663] ? netdev_core_pick_tx (net/core/dev.c:4505) 
[ 21.347852][ T663] __dev_queue_xmit (net/core/dev.c:4596) 
[ 21.347865][ T663] ? sock_alloc_send_pskb (net/core/sock.c:2952) 
[ 21.347874][ T663] ? __pfx___dev_queue_xmit (net/core/dev.c:4538) 
[ 21.347879][ T663] ? packet_parse_headers (./include/linux/skbuff.h:3108 net/packet/af_packet.c:1992) 
[ 21.347891][ T663] ? __pfx_sock_alloc_send_pskb (net/core/sock.c:2922) 
[ 21.347897][ T663] ? __pfx_packet_parse_headers (net/packet/af_packet.c:1977) 
[ 21.347905][ T663] ? dev_get_by_index (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/dev.c:982) 
[ 21.347916][ T663] packet_snd (net/packet/af_packet.c:3131) 
[ 21.347929][ T663] ? __lock_release (kernel/locking/lockdep.c:5527) 
[ 21.347932][ T663] ? __might_fault (mm/memory.c:6858 mm/memory.c:6851) 
[ 21.347939][ T663] ? __pfx_packet_snd (net/packet/af_packet.c:2995) 
[ 21.347942][ T663] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 21)) 
[ 21.347950][ T663] ? lock_acquire (kernel/locking/lockdep.c:5824) 
[ 21.347956][ T663] ? __might_fault (mm/memory.c:6858 mm/memory.c:6851) 
[ 21.347968][ T663] __sys_sendto (net/socket.c:709 net/socket.c:724 net/socket.c:2177) 
[ 21.347976][ T663] ? __pfx___sys_sendto (net/socket.c:2144) 
[ 21.347980][ T663] ? __might_fault (mm/memory.c:6858 mm/memory.c:6851) 
[ 21.348001][ T663] ? fd_install (./arch/x86/include/asm/preempt.h:94 ./include/linux/rcupdate.h:964 fs/file.c:655) 
[ 21.348011][ T663] ? __x64_sys_openat (fs/open.c:1454) 
[ 21.348020][ T663] ? __pfx___x64_sys_openat (fs/open.c:1454) 
[ 21.348023][ T663] ? __pfx_ksys_write (fs/read_write.c:721) 
[ 21.348032][ T663] __x64_sys_sendto (net/socket.c:2180) 
[ 21.348037][ T663] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4349 kernel/locking/lockdep.c:4408) 
[ 21.348042][ T663] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) 
[ 21.348051][ T663] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) 
[   21.348056][  T663] RIP: 0033:0x7fef78040a4a
[ 21.348062][ T663] Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb b8 0f 1f 00 f3 0f 1e fa 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 15 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 7e c3 0f 1f 44 00 00 41 54 48 83 ec 30 44 89
All code
========
   0:	d8 64 89 02          	fsubs  0x2(%rcx,%rcx,4)
   4:	48 c7 c0 ff ff ff ff 	mov    $0xffffffffffffffff,%rax
   b:	eb b8                	jmp    0xffffffffffffffc5
   d:	0f 1f 00             	nopl   (%rax)
  10:	f3 0f 1e fa          	endbr64
  14:	41 89 ca             	mov    %ecx,%r10d
  17:	64 8b 04 25 18 00 00 	mov    %fs:0x18,%eax
  1e:	00 
  1f:	85 c0                	test   %eax,%eax
  21:	75 15                	jne    0x38
  23:	b8 2c 00 00 00       	mov    $0x2c,%eax
  28:	0f 05                	syscall
  2a:*	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax		<-- trapping instruction
  30:	77 7e                	ja     0xb0
  32:	c3                   	ret
  33:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
  38:	41 54                	push   %r12
  3a:	48 83 ec 30          	sub    $0x30,%rsp
  3e:	44                   	rex.R
  3f:	89                   	.byte 0x89

Code starting with the faulting instruction
===========================================
   0:	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax
   6:	77 7e                	ja     0x86
   8:	c3                   	ret
   9:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
   e:	41 54                	push   %r12
  10:	48 83 ec 30          	sub    $0x30,%rsp
  14:	44                   	rex.R
  15:	89                   	.byte 0x89
[   21.348065][  T663] RSP: 002b:00007fffa6285dc8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
[   21.348068][  T663] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fef78040a4a
[   21.348071][  T663] RDX: 0000000000000000 RSI: 00007fffa6285e54 RDI: 0000000000000006
[   21.348072][  T663] RBP: 0000000000000022 R08: 00007fffa6285e20 R09: 0000000000000014
[   21.348074][  T663] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000


Finger prints:
lockdep_rcu_suspicious:dev_hard_start_xmit:sch_direct_xmit:__dev_xmit_skb:__dev_queue_xmit