======================================
| [   23.890078][  T399] 1 lock held by mausezahn/399:
| [ 23.890234][ T399] #0: ffffffffa1d5b5c0 (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) 
| [   23.890515][  T399]
| [   23.890515][  T399] stack backtrace:
[   23.890708][  T399] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   23.890710][  T399] Call Trace:
[   23.890712][  T399]  <TASK>
[ 23.890714][ T399] dump_stack_lvl (lib/dump_stack.c:123) 
[ 23.890723][ T399] lockdep_rcu_suspicious (kernel/locking/lockdep.c:6848) 
[ 23.890735][ T399] 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) 
[ 23.890746][ T399] __dev_queue_xmit (net/core/dev.h:340 net/core/dev.c:4631) 
[ 23.890760][ T399] ? __pfx___dev_queue_xmit (net/core/dev.c:4538) 
[ 23.890764][ T399] ? packet_parse_headers (./include/linux/skbuff.h:3108 net/packet/af_packet.c:1992) 
[ 23.890773][ T399] ? __pfx_sock_alloc_send_pskb (net/core/sock.c:2922) 
[ 23.890780][ T399] ? __pfx_packet_parse_headers (net/packet/af_packet.c:1977) 
[ 23.890785][ T399] ? skb_copy_datagram_from_iter (net/core/datagram.c:564) 
[ 23.890792][ T399] ? dev_get_by_index (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/dev.c:982) 
[ 23.890804][ T399] packet_snd (net/packet/af_packet.c:3131) 
[ 23.890816][ T399] ? __lock_release (kernel/locking/lockdep.c:5527) 
[ 23.890820][ T399] ? __might_fault (mm/memory.c:6858 mm/memory.c:6851) 
[ 23.890829][ T399] ? __pfx_packet_snd (net/packet/af_packet.c:2995) 
[ 23.890831][ T399] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 21)) 
[ 23.890833][ T399] ? __might_fault (mm/memory.c:6858 mm/memory.c:6851) 
[ 23.890840][ T399] ? lock_acquire (kernel/locking/lockdep.c:5824) 
[ 23.890847][ T399] ? __might_fault (mm/memory.c:6858 mm/memory.c:6851) 
[ 23.890857][ T399] __sys_sendto (net/socket.c:709 net/socket.c:724 net/socket.c:2177) 
[ 23.890864][ T399] ? __pfx___sys_sendto (net/socket.c:2144) 
[ 23.890878][ T399] ? sock_ioctl (net/socket.c:1311) 
[ 23.890889][ T399] ? __pfx___up_read (kernel/locking/rwsem.c:1337) 
[ 23.890900][ T399] ? do_user_addr_fault (./include/linux/mmap_lock.h:218 arch/x86/mm/fault.c:1416) 
[ 23.890912][ T399] ? do_user_addr_fault (./include/linux/mmap_lock.h:218 arch/x86/mm/fault.c:1416) 
[ 23.890918][ T399] __x64_sys_sendto (net/socket.c:2180) 
[ 23.890922][ T399] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4349 kernel/locking/lockdep.c:4408) 
[ 23.890927][ T399] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) 
[ 23.890937][ T399] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) 
[   23.890942][  T399] RIP: 0033:0x7f4639e13a4a
[ 23.890946][ T399] 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
[   23.890948][  T399] RSP: 002b:00007ffc3a94d498 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
[   23.890952][  T399] RAX: ffffffffffffffda RBX: 00000000132539d0 RCX: 00007f4639e13a4a
[   23.890954][  T399] RDX: 000000000000002a RSI: 0000000013253c92 RDI: 0000000000000005
[   23.890956][  T399] RBP: 0000000013253c92 R08: 00007ffc3a94d4a0 R09: 0000000000000014
[   23.890958][  T399] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000


Finger prints:
lockdep_rcu_suspicious:dev_hard_start_xmit:__dev_queue_xmit:packet_snd:__sys_sendto