======================================
| xx__-> echo $?
| 0
| xx__-> [   33.700645][    C1] BUG: spinlock bad magic on CPU#1, ip/282
| [ 33.700878][ C1] lock: noop_qdisc+0x240/0x300, .magic: 00000000, .owner: ip/282, .owner_cpu: 1 
[   33.701403][    C1] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[   33.701727][    C1] Call Trace:
[   33.701840][    C1]  <IRQ>
[ 33.701921][ C1] dump_stack_lvl (lib/dump_stack.c:122) 
[ 33.702077][ C1] do_raw_spin_unlock (kernel/locking/spinlock_debug.c:100 kernel/locking/spinlock_debug.c:141) 
[ 33.702238][ C1] _raw_spin_unlock (./arch/x86/include/asm/preempt.h:94 ./include/linux/spinlock_api_smp.h:143 kernel/locking/spinlock.c:186) 
[ 33.702421][ C1] net_tx_action (./include/net/sch_generic.h:226 ./include/net/sch_generic.h:217 ./include/net/pkt_sched.h:128 ./include/net/pkt_sched.h:124 net/core/dev.c:5323) 
[ 33.702568][ C1] handle_softirqs (kernel/softirq.c:554) 
[ 33.702716][ C1] ? dev_deactivate_many (./include/linux/bottom_half.h:33 ./include/linux/netdevice.h:4448 net/sched/sch_generic.c:571 net/sched/sch_generic.c:1363) 
[ 33.702866][ C1] do_softirq (kernel/softirq.c:455 kernel/softirq.c:442) 
[   33.702975][    C1]  </IRQ>
[   33.703049][    C1]  <TASK>
[ 33.703123][ C1] __local_bh_enable_ip (kernel/softirq.c:382) 
[ 33.703266][ C1] dev_deactivate_many (net/sched/sch_generic.c:1356) 
[ 33.703410][ C1] __dev_close_many (net/core/dev.c:1547) 
[ 33.703557][ C1] ? __pfx___dev_close_many (net/core/dev.c:1522) 
[ 33.703701][ C1] ? mark_held_locks (kernel/locking/lockdep.c:4273) 
[ 33.703846][ C1] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4299 kernel/locking/lockdep.c:4358) 
[ 33.704024][ C1] __dev_change_flags (./include/linux/list.h:111 ./include/linux/list.h:215 ./include/linux/list.h:229 net/core/dev.c:1571 net/core/dev.c:8836) 
[ 33.704170][ C1] ? __pfx___dev_change_flags (net/core/dev.c:8802) 
[ 33.704313][ C1] dev_change_flags (net/core/dev.c:8910) 
[ 33.704457][ C1] cycle_netdev (drivers/net/vrf.c:1071) vrf
[ 33.704606][ C1] vrf_add_slave (drivers/net/vrf.c:1102 drivers/net/vrf.c:1121) vrf
[ 33.704755][ C1] do_setlink (net/core/rtnetlink.c:2907) 
[ 33.704901][ C1] ? is_bpf_text_address (./include/linux/rcupdate.h:336 ./include/linux/rcupdate.h:869 ./kernel/bpf/core.c:769) 
[ 33.705048][ C1] ? __pfx_do_setlink (net/core/rtnetlink.c:2778) 
[ 33.705192][ C1] ? is_bpf_text_address (./kernel/bpf/core.c:772) 
[ 33.705338][ C1] ? kernel_text_address (kernel/extable.c:97 kernel/extable.c:94) 
[ 33.705486][ C1] ? __kernel_text_address (kernel/extable.c:79) 
[ 33.705628][ C1] ? unwind_get_return_address (arch/x86/kernel/unwind_orc.c:369 arch/x86/kernel/unwind_orc.c:364) 
[ 33.705771][ C1] ? __pfx_stack_trace_consume_entry (kernel/stacktrace.c:83) 
[ 33.705953][ C1] ? arch_stack_walk (arch/x86/kernel/stacktrace.c:26) 
[ 33.706104][ C1] ? stack_trace_save (kernel/stacktrace.c:123) 
[ 33.706250][ C1] ? __pfx_stack_trace_save (kernel/stacktrace.c:114) 
[ 33.706406][ C1] ? __pfx_validate_nla (lib/nlattr.c:396) 
[ 33.706567][ C1] ? mark_lock (kernel/locking/lockdep.c:4655 (discriminator 3)) 
[ 33.706686][ C1] ? kasan_save_stack (mm/kasan/common.c:49) 
[ 33.706844][ C1] ? __nla_validate_parse (lib/nlattr.c:638) 
[ 33.706998][ C1] __rtnl_newlink (net/core/rtnetlink.c:3696) 
[ 33.707162][ C1] ? 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:227) 
[ 33.707320][ C1] ? __pfx___rtnl_newlink (net/core/rtnetlink.c:3557) 
[ 33.707469][ C1] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4299 kernel/locking/lockdep.c:4358) 
[ 33.707664][ C1] ? __create_object (mm/kmemleak.c:751) 
[ 33.707826][ C1] ? trace_kmalloc (./include/trace/events/kmem.h:54 (discriminator 52)) 
[ 33.707982][ C1] rtnl_newlink (net/core/rtnetlink.c:3744) 
[ 33.708099][ C1] rtnetlink_rcv_msg (net/core/rtnetlink.c:6647) 
[ 33.708255][ C1] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6541) 
[ 33.708409][ C1] ? 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:227) 
[ 33.708564][ C1] ? mark_lock (kernel/locking/lockdep.c:4655 (discriminator 3)) 
[ 33.708680][ C1] ? __lock_acquire (kernel/locking/lockdep.c:5142) 
[ 33.708858][ C1] netlink_rcv_skb (net/netlink/af_netlink.c:2550) 
[ 33.709017][ C1] ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6541) 
[ 33.709173][ C1] ? __pfx_netlink_rcv_skb (net/netlink/af_netlink.c:2527) 
[ 33.709329][ C1] ? netlink_deliver_tap (./include/linux/rcupdate.h:336 ./include/linux/rcupdate.h:869 net/netlink/af_netlink.c:340) 
[ 33.709482][ C1] ? netlink_deliver_tap (./include/linux/rcupdate.h:336 ./include/linux/rcupdate.h:869 ./include/net/netns/generic.h:48 net/netlink/af_netlink.c:333) 
[ 33.709640][ C1] netlink_unicast (net/netlink/af_netlink.c:1331 net/netlink/af_netlink.c:1357) 
[ 33.709793][ C1] ? __pfx_netlink_unicast (net/netlink/af_netlink.c:1342) 
[ 33.709950][ C1] ? find_held_lock (kernel/locking/lockdep.c:5249) 
[ 33.710106][ C1] netlink_sendmsg (net/netlink/af_netlink.c:1901) 
[ 33.710262][ C1] ? __pfx_netlink_sendmsg (net/netlink/af_netlink.c:1820) 
[ 33.710414][ C1] ? __might_fault (mm/memory.c:6388 mm/memory.c:6381) 
[ 33.710570][ C1] ? __import_iovec (lib/iov_iter.c:1263 lib/iov_iter.c:1279) 
[ 33.710730][ C1] ____sys_sendmsg (net/socket.c:730 net/socket.c:745 net/socket.c:2597) 
[ 33.710888][ C1] ? __pfx_____sys_sendmsg (net/socket.c:2543) 
[ 33.711045][ C1] ? __pfx_copy_msghdr_from_user (net/socket.c:2523) 
[ 33.711239][ C1] ? __pfx_validate_chain (kernel/locking/lockdep.c:3824) 
[ 33.711392][ C1] ___sys_sendmsg (net/socket.c:2653) 
[ 33.711550][ C1] ? __pfx____sys_sendmsg (net/socket.c:2640) 
[ 33.711703][ C1] ? find_held_lock (kernel/locking/lockdep.c:5249) 
[ 33.711860][ C1] ? __lock_release (kernel/locking/lockdep.c:5435) 
[ 33.712017][ C1] ? __debug_check_no_obj_freed (lib/debugobjects.c:1001) 
[ 33.712208][ C1] ? __pfx___lock_release (kernel/locking/lockdep.c:5411) 
[ 33.712377][ C1] ? __pfx_do_raw_spin_lock (kernel/locking/spinlock_debug.c:114) 
[ 33.712535][ C1] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4299 kernel/locking/lockdep.c:4358) 
[ 33.712732][ C1] ? __fget_light (./include/linux/atomic/atomic-arch-fallback.h:479 ./include/linux/atomic/atomic-instrumented.h:50 fs/file.c:1145) 
[ 33.712893][ C1] __sys_sendmsg (./include/linux/file.h:34 net/socket.c:2682) 
[ 33.713050][ C1] ? __pfx___sys_sendmsg (net/socket.c:2668) 
[ 33.713206][ C1] ? __virt_addr_valid (./arch/x86/include/asm/preempt.h:94 ./include/linux/rcupdate.h:953 ./include/linux/mmzone.h:2034 arch/x86/mm/physaddr.c:65) 
[ 33.713369][ C1] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) 
[ 33.713534][ C1] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) 
[   33.713731][    C1] RIP: 0033:0x7f59251d67b7
[ 33.713900][ C1] Code: 0a 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b9 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 89 54 24 1c 48 89 74 24 10
All code
========
   0:	0a 00                	or     (%rax),%al
   2:	f7 d8                	neg    %eax
   4:	64 89 02             	mov    %eax,%fs:(%rdx)
   7:	48 c7 c0 ff ff ff ff 	mov    $0xffffffffffffffff,%rax
   e:	eb b9                	jmp    0xffffffffffffffc9
  10:	0f 1f 00             	nopl   (%rax)
  13:	f3 0f 1e fa          	endbr64
  17:	64 8b 04 25 18 00 00 	mov    %fs:0x18,%eax
  1e:	00 
  1f:	85 c0                	test   %eax,%eax
  21:	75 10                	jne    0x33
  23:	b8 2e 00 00 00       	mov    $0x2e,%eax
  28:	0f 05                	syscall
  2a:*	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax		<-- trapping instruction
  30:	77 51                	ja     0x83
  32:	c3                   	ret
  33:	48 83 ec 28          	sub    $0x28,%rsp
  37:	89 54 24 1c          	mov    %edx,0x1c(%rsp)
  3b:	48 89 74 24 10       	mov    %rsi,0x10(%rsp)

Code starting with the faulting instruction
===========================================
   0:	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax
   6:	77 51                	ja     0x59
   8:	c3                   	ret
   9:	48 83 ec 28          	sub    $0x28,%rsp
   d:	89 54 24 1c          	mov    %edx,0x1c(%rsp)
  11:	48 89 74 24 10       	mov    %rsi,0x10(%rsp)
[   33.714443][    C1] RSP: 002b:00007ffdaf6c9488 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[   33.714681][    C1] RAX: ffffffffffffffda RBX: 00007ffdaf6c9bb0 RCX: 00007f59251d67b7
[   33.714914][    C1] RDX: 0000000000000000 RSI: 00007ffdaf6c94f0 RDI: 0000000000000005
[   33.715141][    C1] RBP: 0000000000000004 R08: 0000000000000003 R09: 0000000000000000
[   33.715372][    C1] R10: 0000000019e3a910 R11: 0000000000000246 R12: 0000000000000004


Finger prints:
do_raw_spin_unlock:_raw_spin_unlock:net_tx_action:handle_softirqs:do_softirq