======================================
| [ 35.383934][ C1] ret_from_fork_asm (arch/x86/entry/entry_64.S:256) 
| [   35.384114][    C1]
| [   35.384205][    C1]
| [   35.384205][    C1] stack backtrace:
[   35.384709][    C1] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[   35.385105][    C1] Workqueue: ipv6_addrconf addrconf_dad_work
[   35.385334][    C1] Call Trace:
[   35.385470][    C1]  <IRQ>
[ 35.385566][ C1] dump_stack_lvl (lib/dump_stack.c:117) 
[ 35.385761][ C1] print_irq_inversion_bug.part.0 (kernel/locking/lockdep.c:4024) 
[ 35.386109][ C1] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:256) 
[ 35.386290][ C1] ? __pfx_print_irq_inversion_bug.part.0 (kernel/locking/lockdep.c:4024) 
[ 35.386511][ C1] ? __pfx_usage_skip (kernel/locking/lockdep.c:2264) 
[ 35.386703][ C1] ? __pfx_usage_match (kernel/locking/lockdep.c:2256) 
[ 35.387011][ C1] ? arch_stack_walk (arch/x86/kernel/stacktrace.c:24) 
[ 35.387191][ C1] mark_lock_irq (kernel/locking/lockdep.c:4244) 
[ 35.387370][ C1] ? __pfx_mark_lock_irq (kernel/locking/lockdep.c:4207) 
[ 35.387550][ C1] ? stack_trace_save (kernel/stacktrace.c:123) 
[ 35.387893][ C1] ? save_trace (kernel/locking/lockdep.c:586) 
[ 35.388076][ C1] mark_lock (kernel/locking/lockdep.c:4678) 
[ 35.388213][ C1] mark_usage (kernel/locking/lockdep.c:4567) 
[ 35.388351][ C1] __lock_acquire (kernel/locking/lockdep.c:5091) 
[ 35.388533][ C1] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5756) 
[ 35.388844][ C1] ? ipv6_get_lladdr (net/ipv6/addrconf.c:1911 net/ipv6/addrconf.c:1934) 
[ 35.389024][ C1] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 35.389211][ C1] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 52)) 
[ 35.389395][ C1] ? ipv6_get_lladdr (net/ipv6/addrconf.c:1911 net/ipv6/addrconf.c:1934) 
[ 35.389832][ C1] ? lock_acquire (kernel/locking/lockdep.c:5727) 
[ 35.390012][ C1] ? ipv6_get_lladdr (net/ipv6/addrconf.c:1911 net/ipv6/addrconf.c:1934) 
[ 35.390191][ C1] _raw_read_lock_bh (./include/linux/rwlock_api_smp.h:177 kernel/locking/spinlock.c:252) 
[ 35.390370][ C1] ? ipv6_get_lladdr (net/ipv6/addrconf.c:1911 net/ipv6/addrconf.c:1934) 
[ 35.390549][ C1] ipv6_get_lladdr (net/ipv6/addrconf.c:1911 net/ipv6/addrconf.c:1934) 
[ 35.390871][ C1] ndisc_send_ns (net/ipv6/ndisc.c:658) 
[ 35.391051][ C1] ? __pfx_ndisc_send_ns (net/ipv6/ndisc.c:653) 
[ 35.391233][ C1] ? __ipv6_chk_addr_and_flags (net/ipv6/addrconf.c:2009) 
[ 35.391460][ C1] ndisc_solicit (net/ipv6/ndisc.c:736) 
[ 35.391776][ C1] ? __pfx_ndisc_solicit (net/ipv6/ndisc.c:736) 
[ 35.391956][ C1] ? neigh_probe (net/core/neighbour.c:1074) 
[ 35.392136][ C1] neigh_probe (net/core/neighbour.c:1075) 
[ 35.392272][ C1] __neigh_event_send (net/core/neighbour.c:1242) 
[ 35.392457][ C1] neigh_resolve_output (net/core/neighbour.c:1547) 
[ 35.392636][ C1] ? __local_bh_enable_ip (./arch/x86/include/asm/irqflags.h:42 ./arch/x86/include/asm/irqflags.h:77 kernel/softirq.c:387) 
[ 35.392824][ C1] ? ___neigh_create (net/core/neighbour.c:722 (discriminator 9)) 
[ 35.393009][ C1] ip6_finish_output2 (./include/net/neighbour.h:542 net/ipv6/ip6_output.c:137) 
[ 35.393190][ C1] ip6_finish_output (net/ipv6/ip6_output.c:211 net/ipv6/ip6_output.c:222) 
[ 35.393369][ C1] ip6_output (./include/linux/netfilter.h:303 net/ipv6/ip6_output.c:243) 
[ 35.393508][ C1] ? __pfx_ip6_output (net/ipv6/ip6_output.c:230) 
[ 35.393695][ C1] ? pskb_expand_head (./arch/x86/include/asm/atomic.h:28 ./include/linux/atomic/atomic-arch-fallback.h:503 ./include/linux/atomic/atomic-instrumented.h:68 net/core/skbuff.c:2267) 
[ 35.393874][ C1] ? ip6_mtu (./include/linux/rcupdate.h:339 ./include/linux/rcupdate.h:814 ./include/net/ip6_route.h:336 net/ipv6/route.c:3217) 
[ 35.394136][ C1] ? ip6_local_out (net/ipv6/output_core.c:154) 
[ 35.394318][ C1] udp_tunnel6_xmit_skb (./include/net/ip6_tunnel.h:163 net/ipv6/ip6_udp_tunnel.c:111) ip6_udp_tunnel
[ 35.394548][ C1] vxlan_xmit_one (drivers/net/vxlan/vxlan_core.c:2551) vxlan
[ 35.394751][ C1] ? stack_access_ok (arch/x86/kernel/unwind_orc.c:396) 
[ 35.395059][ C1] ? ip6_fraglist_init (./include/linux/skbuff.h:2711 net/ipv6/ip6_output.c:715) 
[ 35.395238][ C1] ? __pfx_vxlan_xmit_one (drivers/net/vxlan/vxlan_core.c:2313) vxlan
[ 35.395476][ C1] ? __lock_acquire (kernel/locking/lockdep.c:5137) 
[ 35.395663][ C1] ? orc_sort_cmp (arch/x86/kernel/unwind_orc.c:80 arch/x86/kernel/unwind_orc.c:271) 
[ 35.395976][ C1] ? __dev_queue_xmit (./include/linux/bottom_half.h:20 ./include/linux/rcupdate.h:833 net/core/dev.c:4297) 
[ 35.396156][ C1] ? lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5756) 
[ 35.396342][ C1] ? vxlan_xmit (drivers/net/vxlan/vxlan_core.c:2766) vxlan
[ 35.396533][ C1] vxlan_xmit (drivers/net/vxlan/vxlan_core.c:2766) vxlan
[ 35.396863][ C1] dev_hard_start_xmit (./include/linux/netdevice.h:4875 ./include/linux/netdevice.h:4889 net/core/dev.c:3563 net/core/dev.c:3579) 
[ 35.397044][ C1] ? validate_xmit_skb.constprop.0 (net/core/dev.c:3634) 
[ 35.397267][ C1] __dev_queue_xmit (net/core/dev.h:167 net/core/dev.c:4373) 
[ 35.397447][ C1] ? find_held_lock (kernel/locking/lockdep.c:5244) 
[ 35.397753][ C1] ? __pfx___dev_queue_xmit (net/core/dev.c:4281) 
[ 35.397933][ C1] ? __lock_release (kernel/locking/lockdep.c:5430) 
[ 35.398120][ C1] ? __pfx___lock_release (kernel/locking/lockdep.c:5406) 
[ 35.398300][ C1] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 35.398480][ C1] br_dev_queue_push_xmit (net/bridge/br_forward.c:34) bridge
[ 35.398865][ C1] ? __pfx_br_dev_queue_push_xmit (net/bridge/br_forward.c:34) bridge
[ 35.399125][ C1] ? __br_forward (./include/linux/netfilter.h:314 ./include/linux/netfilter.h:308 net/bridge/br_forward.c:115) bridge
[ 35.399344][ C1] deliver_clone (net/bridge/br_forward.c:132) bridge
[ 35.399557][ C1] br_handle_frame_finish (net/bridge/br_input.c:215) bridge
[ 35.399835][ C1] ? __pfx_br_handle_frame_finish (net/bridge/br_input.c:75) bridge
[ 35.400093][ C1] ? common_startup_64 (arch/x86/kernel/head_64.S:421) 
[ 35.400277][ C1] ? schedule_on_each_cpu (kernel/workqueue.c:4226 (discriminator 3) kernel/workqueue.c:4419 (discriminator 3)) 
[ 35.400588][ C1] ? __pfx_stack_trace_consume_entry (kernel/stacktrace.c:83) 
[ 35.400812][ C1] ? arch_stack_walk (arch/x86/kernel/stacktrace.c:24) 
[ 35.400995][ C1] br_handle_frame (net/bridge/br_input.c:417) bridge
[ 35.401209][ C1] ? __pfx_br_handle_frame (net/bridge/br_input.c:321) bridge
[ 35.401469][ C1] __netif_receive_skb_core.constprop.0 (net/core/dev.c:5498) 
[ 35.401697][ C1] ? __lock_acquire (kernel/locking/lockdep.c:5137) 
[ 35.401876][ C1] ? __pfx___netif_receive_skb_core.constprop.0 (net/core/dev.c:5391) 
[ 35.402100][ C1] ? lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5756) 
[ 35.402279][ C1] ? process_backlog (./include/linux/rcupdate.h:329 ./include/linux/rcupdate.h:781 net/core/dev.c:6046) 
[ 35.402459][ C1] __netif_receive_skb_one_core (net/core/dev.c:5603) 
[ 35.402685][ C1] ? __pfx___netif_receive_skb_one_core (net/core/dev.c:5597) 
[ 35.403035][ C1] ? process_backlog (./include/linux/rcupdate.h:329 ./include/linux/rcupdate.h:781 net/core/dev.c:6046) 
[ 35.403212][ C1] ? lock_acquire (kernel/locking/lockdep.c:5727) 
[ 35.403390][ C1] ? process_backlog (./include/linux/rcupdate.h:329 ./include/linux/rcupdate.h:781 net/core/dev.c:6046) 
[ 35.403569][ C1] process_backlog (./include/linux/rcupdate.h:810 net/core/dev.c:6048) 
[ 35.403760][ C1] ? find_held_lock (kernel/locking/lockdep.c:5244) 
[ 35.404191][ C1] __napi_poll.constprop.0 (net/core/dev.c:6701) 
[ 35.404370][ C1] net_rx_action (net/core/dev.c:6770 net/core/dev.c:6886) 
[ 35.404551][ C1] ? __pfx_net_rx_action (net/core/dev.c:6850) 
[ 35.404732][ C1] ? usage_skip (kernel/locking/lockdep.c:2295 kernel/locking/lockdep.c:2263) 
[ 35.405037][ C1] ? mark_held_locks (kernel/locking/lockdep.c:4274) 
[ 35.405216][ C1] __do_softirq (kernel/softirq.c:554) 
[ 35.405394][ C1] ? __dev_queue_xmit (./include/linux/rcupdate.h:339 ./include/linux/rcupdate.h:849 net/core/dev.c:4399) 
[ 35.405583][ C1] do_softirq (kernel/softirq.c:455 kernel/softirq.c:442) 
[   35.405843][    C1]  </IRQ>
[   35.405936][    C1]  <TASK>
[ 35.406027][ C1] __local_bh_enable_ip (kernel/softirq.c:382) 
[ 35.406204][ C1] ? __dev_queue_xmit (./include/linux/rcupdate.h:339 ./include/linux/rcupdate.h:849 net/core/dev.c:4399) 
[ 35.406384][ C1] __dev_queue_xmit (net/core/dev.c:4400) 
[ 35.406563][ C1] ? mark_lock (kernel/locking/lockdep.c:4656 (discriminator 3)) 
[ 35.406823][ C1] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 52)) 
[ 35.407002][ C1] ? mark_held_locks (kernel/locking/lockdep.c:4274) 
[ 35.407181][ C1] ? eth_header (net/ethernet/eth.c:100) 
[ 35.407362][ C1] ? __pfx___dev_queue_xmit (net/core/dev.c:4281) 
[ 35.407692][ C1] ip6_finish_output2 (./include/net/neighbour.h:542 net/ipv6/ip6_output.c:137) 
[ 35.407876][ C1] ip6_finish_output (net/ipv6/ip6_output.c:211 net/ipv6/ip6_output.c:222) 
[ 35.408055][ C1] ip6_output (./include/linux/netfilter.h:303 net/ipv6/ip6_output.c:243) 
[ 35.408196][ C1] ? __pfx_ip6_output (net/ipv6/ip6_output.c:230) 
[ 35.408375][ C1] ? lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5756) 
[ 35.408554][ C1] ? find_held_lock (kernel/locking/lockdep.c:5244) 
[ 35.408732][ C1] ? __lock_release (kernel/locking/lockdep.c:5430) 
[ 35.408911][ C1] ? icmp6_dst_alloc (net/ipv6/route.c:3293) 
[ 35.409091][ C1] NF_HOOK.constprop.0 (./include/linux/rcupdate.h:329 ./include/linux/rcupdate.h:781 ./include/linux/netfilter.h:238 ./include/linux/netfilter.h:312) 
[ 35.409286][ C1] ? __pfx_NF_HOOK.constprop.0 (./include/linux/netfilter.h:308) 
[ 35.409465][ C1] ? __pfx_xfrm_lookup_with_ifid (net/xfrm/xfrm_policy.c:3136) 
[ 35.409693][ C1] ? lockdep_hardirqs_on_prepare.part.0 (kernel/locking/lockdep.c:4300 kernel/locking/lockdep.c:4359) 
[ 35.409915][ C1] ? icmp6_dst_alloc (net/ipv6/route.c:3293) 
[ 35.410217][ C1] ? __local_bh_enable_ip (./arch/x86/include/asm/irqflags.h:42 ./arch/x86/include/asm/irqflags.h:77 kernel/softirq.c:387) 
[ 35.410396][ C1] mld_sendpack (net/ipv6/mcast.c:1822) 
[ 35.410577][ C1] ? __pfx_mld_sendpack (net/ipv6/mcast.c:1779) 
[ 35.410758][ C1] ipv6_mc_dad_complete (./include/linux/refcount.h:192 net/ipv6/mcast.c:2244) 
[ 35.411062][ C1] addrconf_dad_completed (net/ipv6/addrconf.c:4341) 
[ 35.411242][ 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:228) 
[ 35.411422][ C1] ? __pfx_addrconf_dad_completed (net/ipv6/addrconf.c:4307) 
[ 35.411644][ C1] ? mark_held_locks (kernel/locking/lockdep.c:4274) 
[ 35.411962][ C1] ? addrconf_dad_work (net/ipv6/addrconf.c:4268) 
[ 35.412141][ C1] addrconf_dad_work (net/ipv6/addrconf.c:4268) 
[ 35.412318][ C1] ? __pfx_addrconf_dad_work (net/ipv6/addrconf.c:4178) 
[ 35.412496][ C1] ? process_one_work (kernel/workqueue.c:3230) 
[ 35.412800][ C1] ? lock_acquire (kernel/locking/lockdep.c:5727) 
[ 35.412978][ C1] ? process_one_work (kernel/workqueue.c:3230) 
[ 35.413162][ C1] process_one_work (kernel/workqueue.c:3254) 
[ 35.413342][ C1] ? __pfx___lock_release (kernel/locking/lockdep.c:5406) 
[ 35.413646][ C1] ? __pfx_process_one_work (kernel/workqueue.c:3156) 
[ 35.413827][ C1] ? assign_work (kernel/workqueue.c:1209) 
[ 35.414005][ C1] worker_thread (kernel/workqueue.c:3329 kernel/workqueue.c:3416) 
[ 35.414187][ C1] ? __pfx_worker_thread (kernel/workqueue.c:3362) 
[ 35.414368][ C1] kthread (kernel/kthread.c:388) 
[ 35.414504][ C1] ? __pfx_kthread (kernel/kthread.c:341) 
[ 35.414684][ C1] ret_from_fork (arch/x86/kernel/process.c:147) 
[ 35.414863][ C1] ? __pfx_kthread (kernel/kthread.c:341) 


Finger prints:
ret_from_fork_asm:dump_stack_lvl:mark_lock_irq:mark_lock