======================================
| [  986.592003][T12371] 1 lock held by ra6/12371:
| [986.592166][T12371] #0: ffffffffa296f640 (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) 
| [  986.592494][T12371]
| [  986.592494][T12371] stack backtrace:
[  986.592688][T12371] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  986.592691][T12371] Call Trace:
[  986.592693][T12371]  <TASK>
[986.592695][T12371] dump_stack_lvl (lib/dump_stack.c:123) 
[986.592706][T12371] lockdep_rcu_suspicious (kernel/locking/lockdep.c:6848) 
[986.592718][T12371] 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) 
[986.592738][T12371] __dev_queue_xmit (net/core/dev.h:340 net/core/dev.c:4631) 
[986.592745][T12371] ? _copy_from_iter (./arch/x86/include/asm/uaccess_64.h:126 ./arch/x86/include/asm/uaccess_64.h:141 lib/iov_iter.c:55 ./include/linux/iov_iter.h:30 ./include/linux/iov_iter.h:300 ./include/linux/iov_iter.h:328 lib/iov_iter.c:249 lib/iov_iter.c:260) 
[986.592765][T12371] ? __pfx___dev_queue_xmit (net/core/dev.c:4538) 
[986.592770][T12371] ? packet_parse_headers (./include/linux/skbuff.h:3108 net/packet/af_packet.c:1992) 
[986.592782][T12371] ? __pfx_sock_alloc_send_pskb (net/core/sock.c:2922) 
[986.592790][T12371] ? __pfx_packet_parse_headers (net/packet/af_packet.c:1977) 
[986.592794][T12371] ? skb_copy_datagram_from_iter (net/core/datagram.c:564) 
[986.592803][T12371] ? packet_cached_dev_get (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 net/packet/af_packet.c:295) 
[986.592813][T12371] packet_snd (net/packet/af_packet.c:3131) 
[986.592825][T12371] ? hlock_class (./arch/x86/include/asm/bitops.h:227 ./arch/x86/include/asm/bitops.h:239 ./include/asm-generic/bitops/instrumented-non-atomic.h:142 kernel/locking/lockdep.c:230) 
[986.592830][T12371] ? mark_lock (kernel/locking/lockdep.c:4729 (discriminator 3)) 
[986.592835][T12371] ? __pfx_packet_snd (net/packet/af_packet.c:2995) 
[986.592843][T12371] ? __lock_acquire (kernel/locking/lockdep.c:5228) 
[986.592859][T12371] __sys_sendto (net/socket.c:709 net/socket.c:724 net/socket.c:2177) 
[986.592866][T12371] ? __pfx___sys_sendto (net/socket.c:2144) 
[986.592880][T12371] ? __lock_release (kernel/locking/lockdep.c:5527) 
[986.592882][T12371] ? do_user_addr_fault (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 ./include/linux/mm.h:742 arch/x86/mm/fault.c:1339) 
[986.592889][T12371] ? __pfx___lock_release (kernel/locking/lockdep.c:5503) 
[986.592892][T12371] ? __up_read (./arch/x86/include/asm/atomic64_64.h:79 ./include/linux/atomic/atomic-arch-fallback.h:2749 ./include/linux/atomic/atomic-long.h:184 ./include/linux/atomic/atomic-instrumented.h:3317 kernel/locking/rwsem.c:1345) 
[986.592898][T12371] ? __pfx___up_read (kernel/locking/rwsem.c:1337) 
[986.592905][T12371] ? do_user_addr_fault (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 ./include/linux/mm.h:742 arch/x86/mm/fault.c:1339) 
[986.592913][T12371] ? do_user_addr_fault (./include/linux/rcupdate.h:882 ./include/linux/mm.h:742 arch/x86/mm/fault.c:1339) 
[986.592920][T12371] __x64_sys_sendto (net/socket.c:2180) 
[986.592925][T12371] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4349 kernel/locking/lockdep.c:4408) 
[986.592930][T12371] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) 
[986.592939][T12371] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) 
[  986.592944][T12371] RIP: 0033:0x7f1a080b18f0
[ 986.592949][T12371] Code: ff ff 64 89 02 eb bd 0f 1f 00 f3 0f 1e fa 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 1d 45 31 c9 45 31 c0 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 68 c3 0f 1f 80 00 00 00 00 41 54 48 83 ec 20
All code
========
   0:	ff                   	(bad)
   1:	ff 64 89 02          	jmp    *0x2(%rcx,%rcx,4)
   5:	eb bd                	jmp    0xffffffffffffffc4
   7:	0f 1f 00             	nopl   (%rax)
   a:	f3 0f 1e fa          	endbr64
   e:	41 89 ca             	mov    %ecx,%r10d
  11:	64 8b 04 25 18 00 00 	mov    %fs:0x18,%eax
  18:	00 
  19:	85 c0                	test   %eax,%eax
  1b:	75 1d                	jne    0x3a
  1d:	45 31 c9             	xor    %r9d,%r9d
  20:	45 31 c0             	xor    %r8d,%r8d
  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 68                	ja     0x9a
  32:	c3                   	ret
  33:	0f 1f 80 00 00 00 00 	nopl   0x0(%rax)
  3a:	41 54                	push   %r12
  3c:	48 83 ec 20          	sub    $0x20,%rsp

Code starting with the faulting instruction
===========================================
   0:	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax
   6:	77 68                	ja     0x70
   8:	c3                   	ret
   9:	0f 1f 80 00 00 00 00 	nopl   0x0(%rax)
  10:	41 54                	push   %r12
  12:	48 83 ec 20          	sub    $0x20,%rsp
[  986.592952][T12371] RSP: 002b:00007ffc26744568 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
[  986.592956][T12371] RAX: ffffffffffffffda RBX: 000000002c6f7e50 RCX: 00007f1a080b18f0
[  986.592958][T12371] RDX: 0000000000000046 RSI: 0000000000417940 RDI: 0000000000000006
[  986.592960][T12371] RBP: 00007ffc267445c0 R08: 0000000000000000 R09: 0000000000000000
[  986.592962][T12371] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc267450a8


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