======================================
| [   25.402493][  T404] 1 lock held by mausezahn/404:
| [ 25.402646][ T404] #0: ffffffff9d15b5c0 (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) 
| [   25.402931][  T404]
| [   25.402931][  T404] stack backtrace:
[   25.403140][  T404] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   25.403143][  T404] Call Trace:
[   25.403145][  T404]  <TASK>
[ 25.403147][ T404] dump_stack_lvl (lib/dump_stack.c:123) 
[ 25.403156][ T404] lockdep_rcu_suspicious (kernel/locking/lockdep.c:6848) 
[ 25.403168][ T404] 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) 
[ 25.403178][ T404] __dev_queue_xmit (net/core/dev.h:340 net/core/dev.c:4631) 
[ 25.403192][ T404] ? __pfx___dev_queue_xmit (net/core/dev.c:4538) 
[ 25.403196][ T404] ? packet_parse_headers (./include/linux/skbuff.h:3108 net/packet/af_packet.c:1992) 
[ 25.403206][ T404] ? __pfx_sock_alloc_send_pskb (net/core/sock.c:2922) 
[ 25.403212][ T404] ? __pfx_packet_parse_headers (net/packet/af_packet.c:1977) 
[ 25.403217][ T404] ? skb_copy_datagram_from_iter (net/core/datagram.c:564) 
[ 25.403223][ T404] ? dev_get_by_index (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/core/dev.c:982) 
[ 25.403235][ T404] packet_snd (net/packet/af_packet.c:3131) 
[ 25.403246][ T404] ? __lock_release (kernel/locking/lockdep.c:5527) 
[ 25.403250][ T404] ? __might_fault (mm/memory.c:6858 mm/memory.c:6851) 
[ 25.403258][ T404] ? __pfx_packet_snd (net/packet/af_packet.c:2995) 
[ 25.403260][ T404] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 21)) 
[ 25.403263][ T404] ? __might_fault (mm/memory.c:6858 mm/memory.c:6851) 
[ 25.403270][ T404] ? lock_acquire (kernel/locking/lockdep.c:5824) 
[ 25.403276][ T404] ? __might_fault (mm/memory.c:6858 mm/memory.c:6851) 
[ 25.403287][ T404] __sys_sendto (net/socket.c:709 net/socket.c:724 net/socket.c:2177) 
[ 25.403293][ T404] ? __pfx___sys_sendto (net/socket.c:2144) 
[ 25.403308][ T404] ? sock_ioctl (net/socket.c:1311) 
[ 25.403318][ T404] ? __pfx___up_read (kernel/locking/rwsem.c:1337) 
[ 25.403328][ T404] ? do_user_addr_fault (./include/linux/mmap_lock.h:218 arch/x86/mm/fault.c:1416) 
[ 25.403339][ T404] ? do_user_addr_fault (./include/linux/mmap_lock.h:218 arch/x86/mm/fault.c:1416) 
[ 25.403346][ T404] __x64_sys_sendto (net/socket.c:2180) 
[ 25.403350][ T404] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4349 kernel/locking/lockdep.c:4408) 
[ 25.403355][ T404] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) 
[ 25.403364][ T404] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) 
[   25.403370][  T404] RIP: 0033:0x7f64f6d75a4a
[ 25.403374][ T404] 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
[   25.403377][  T404] RSP: 002b:00007fff14ab5b68 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
[   25.403381][  T404] RAX: ffffffffffffffda RBX: 00000000095029d0 RCX: 00007f64f6d75a4a
[   25.403384][  T404] RDX: 000000000000002a RSI: 0000000009502c92 RDI: 0000000000000005
[   25.403386][  T404] RBP: 0000000009502c92 R08: 00007fff14ab5b70 R09: 0000000000000014
[   25.403388][  T404] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000


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