======================================
| [   26.331517][  T421] 1 lock held by mausezahn/421:
| [ 26.331700][ T421] #0: ffffffffb8f5b5c0 (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) 
| [   26.332020][  T421]
| [   26.332020][  T421] stack backtrace:
[   26.332259][  T421] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   26.332261][  T421] Call Trace:
[   26.332264][  T421]  <TASK>
[ 26.332267][ T421] dump_stack_lvl (lib/dump_stack.c:123) 
[ 26.332275][ T421] lockdep_rcu_suspicious (kernel/locking/lockdep.c:6848) 
[ 26.332288][ T421] 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) 
[ 26.332298][ T421] __dev_queue_xmit (net/core/dev.h:340 net/core/dev.c:4631) 
[ 26.332312][ T421] ? __pfx___dev_queue_xmit (net/core/dev.c:4538) 
[ 26.332317][ T421] ? packet_parse_headers (./include/linux/skbuff.h:3108 net/packet/af_packet.c:1992) 
[ 26.332326][ T421] ? __pfx_sock_alloc_send_pskb (net/core/sock.c:2922) 
[ 26.332333][ T421] ? __pfx_packet_parse_headers (net/packet/af_packet.c:1977) 
[ 26.332337][ T421] ? skb_copy_datagram_from_iter (net/core/datagram.c:564) 
[ 26.332343][ T421] ? dev_get_by_index (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/dev.c:982) 
[ 26.332356][ T421] packet_snd (net/packet/af_packet.c:3131) 
[ 26.332367][ T421] ? __lock_release (kernel/locking/lockdep.c:5527) 
[ 26.332371][ T421] ? __might_fault (mm/memory.c:6858 mm/memory.c:6851) 
[ 26.332379][ T421] ? __pfx_packet_snd (net/packet/af_packet.c:2995) 
[ 26.332381][ T421] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 21)) 
[ 26.332384][ T421] ? __might_fault (mm/memory.c:6858 mm/memory.c:6851) 
[ 26.332390][ T421] ? lock_acquire (kernel/locking/lockdep.c:5824) 
[ 26.332397][ T421] ? __might_fault (mm/memory.c:6858 mm/memory.c:6851) 
[ 26.332408][ T421] __sys_sendto (net/socket.c:709 net/socket.c:724 net/socket.c:2177) 
[ 26.332414][ T421] ? __pfx___sys_sendto (net/socket.c:2144) 
[ 26.332428][ T421] ? sock_ioctl (net/socket.c:1311) 
[ 26.332441][ T421] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4349 kernel/locking/lockdep.c:4408) 
[ 26.332457][ T421] __x64_sys_sendto (net/socket.c:2180) 
[ 26.332460][ T421] ? __pfx___x64_sys_sendto (net/socket.c:2180) 
[ 26.332466][ T421] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) 
[ 26.332474][ T421] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) 
[   26.332480][  T421] RIP: 0033:0x7fcdd6d9da4a
[ 26.332486][ T421] 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
[   26.332489][  T421] RSP: 002b:00007ffcbd7522c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
[   26.332493][  T421] RAX: ffffffffffffffda RBX: 000000001ead69d0 RCX: 00007fcdd6d9da4a
[   26.332495][  T421] RDX: 0000000000000062 RSI: 000000001ead65c2 RDI: 0000000000000005
[   26.332497][  T421] RBP: 000000001ead65c2 R08: 00007ffcbd7522d0 R09: 0000000000000014
[   26.332499][  T421] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000


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