======================================
| [ 35.951664][ C0] ret_from_fork_asm (arch/x86/entry/entry_64.S:256) 
| [   35.951843][    C0]
| [   35.952124][    C0]
| [   35.952124][    C0] stack backtrace:
[   35.952685][    C0] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[   35.953109][    C0] Workqueue: ipv6_addrconf addrconf_dad_work
[   35.953381][    C0] Call Trace:
[   35.953521][    C0]  <IRQ>
[ 35.953615][ C0] dump_stack_lvl (lib/dump_stack.c:117) 
[ 35.953829][ C0] print_irq_inversion_bug.part.0 (kernel/locking/lockdep.c:4024) 
[ 35.954070][ C0] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:256) 
[ 35.954272][ C0] ? __pfx_print_irq_inversion_bug.part.0 (kernel/locking/lockdep.c:4024) 
[ 35.954522][ C0] ? __pfx_usage_skip (kernel/locking/lockdep.c:2264) 
[ 35.954700][ C0] ? __pfx_usage_match (kernel/locking/lockdep.c:2256) 
[ 35.954899][ C0] ? arch_stack_walk (arch/x86/kernel/stacktrace.c:24) 
[ 35.955098][ C0] mark_lock_irq (kernel/locking/lockdep.c:4244) 
[ 35.955288][ C0] ? __pfx_mark_lock_irq (kernel/locking/lockdep.c:4207) 
[ 35.955636][ C0] ? stack_trace_save (kernel/stacktrace.c:123) 
[ 35.955858][ C0] ? save_trace (kernel/locking/lockdep.c:586) 
[ 35.956054][ C0] mark_lock (kernel/locking/lockdep.c:4678) 
[ 35.956216][ C0] mark_usage (kernel/locking/lockdep.c:4567) 
[ 35.956351][ C0] __lock_acquire (kernel/locking/lockdep.c:5091) 
[ 35.956679][ C0] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5756) 
[ 35.956864][ C0] ? ipv6_get_lladdr (net/ipv6/addrconf.c:1911 net/ipv6/addrconf.c:1934) 
[ 35.957042][ C0] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 35.957219][ C0] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 52)) 
[ 35.957518][ C0] ? ipv6_get_lladdr (net/ipv6/addrconf.c:1911 net/ipv6/addrconf.c:1934) 
[ 35.957695][ C0] ? lock_acquire (kernel/locking/lockdep.c:5727) 
[ 35.957874][ C0] ? ipv6_get_lladdr (net/ipv6/addrconf.c:1911 net/ipv6/addrconf.c:1934) 
[ 35.958051][ C0] _raw_read_lock_bh (./include/linux/rwlock_api_smp.h:177 kernel/locking/spinlock.c:252) 
[ 35.958354][ C0] ? ipv6_get_lladdr (net/ipv6/addrconf.c:1911 net/ipv6/addrconf.c:1934) 
[ 35.958531][ C0] ipv6_get_lladdr (net/ipv6/addrconf.c:1911 net/ipv6/addrconf.c:1934) 
[ 35.958709][ C0] ndisc_send_ns (net/ipv6/ndisc.c:658) 
[ 35.958887][ C0] ? __pfx_ndisc_send_ns (net/ipv6/ndisc.c:653) 
[ 35.959065][ C0] ? __ipv6_chk_addr_and_flags (net/ipv6/addrconf.c:2009) 
[ 35.959434][ C0] ndisc_solicit (net/ipv6/ndisc.c:736) 
[ 35.959622][ C0] ? __pfx_ndisc_solicit (net/ipv6/ndisc.c:736) 
[ 35.959823][ C0] ? neigh_probe (net/core/neighbour.c:1074) 
[ 35.960003][ C0] neigh_probe (net/core/neighbour.c:1075) 
[ 35.960423][ C0] __neigh_event_send (net/core/neighbour.c:1242) 
[ 35.960624][ C0] neigh_resolve_output (net/core/neighbour.c:1547) 
[ 35.960802][ C0] ? __local_bh_enable_ip (./arch/x86/include/asm/irqflags.h:42 ./arch/x86/include/asm/irqflags.h:77 kernel/softirq.c:387) 
[ 35.960992][ C0] ? ___neigh_create (net/core/neighbour.c:722 (discriminator 9)) 
[ 35.961323][ C0] ip6_finish_output2 (./include/net/neighbour.h:542 net/ipv6/ip6_output.c:137) 
[ 35.961501][ C0] ip6_finish_output (net/ipv6/ip6_output.c:211 net/ipv6/ip6_output.c:222) 
[ 35.961682][ C0] ip6_output (./include/linux/netfilter.h:303 net/ipv6/ip6_output.c:243) 
[ 35.961816][ C0] ? __pfx_ip6_output (net/ipv6/ip6_output.c:230) 
[ 35.961994][ C0] ? 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) 
[ 35.962293][ C0] ? ip6_mtu (./include/linux/rcupdate.h:339 ./include/linux/rcupdate.h:814 ./include/net/ip6_route.h:336 net/ipv6/route.c:3217) 
[ 35.962432][ C0] ? ip6_local_out (net/ipv6/output_core.c:154) 
[ 35.962611][ C0] udp_tunnel6_xmit_skb (./include/net/ip6_tunnel.h:163 net/ipv6/ip6_udp_tunnel.c:111) ip6_udp_tunnel
[ 35.962836][ C0] vxlan_xmit_one (drivers/net/vxlan/vxlan_core.c:2551) vxlan
[ 35.963181][ C0] ? find_held_lock (kernel/locking/lockdep.c:5244) 
[ 35.963362][ C0] ? migrate_device_coherent_page (./include/linux/pagemap.h:1069 mm/migrate_device.c:952) 
[ 35.963584][ C0] ? __pfx_vxlan_xmit_one (drivers/net/vxlan/vxlan_core.c:2313) vxlan
[ 35.963822][ C0] ? mark_held_locks (kernel/locking/lockdep.c:4274) 
[ 35.964000][ C0] ? lockdep_hardirqs_on_prepare.part.0 (kernel/locking/lockdep.c:4292 kernel/locking/lockdep.c:4359) 
[ 35.964223][ C0] ? kmem_cache_alloc (mm/slub.c:3858) 
[ 35.964402][ C0] ? __copy_skb_header (./include/net/dst.h:290 net/core/skbuff.c:1501) 
[ 35.964583][ C0] ? vxlan_xmit (drivers/net/vxlan/vxlan_core.c:2763) vxlan
[ 35.964775][ C0] vxlan_xmit (drivers/net/vxlan/vxlan_core.c:2763) vxlan
[ 35.964970][ C0] dev_hard_start_xmit (./include/linux/netdevice.h:4875 ./include/linux/netdevice.h:4889 net/core/dev.c:3563 net/core/dev.c:3579) 
[ 35.965148][ C0] ? validate_xmit_skb.constprop.0 (net/core/dev.c:3634) 
[ 35.965369][ C0] __dev_queue_xmit (net/core/dev.h:167 net/core/dev.c:4373) 
[ 35.965549][ C0] ? find_held_lock (kernel/locking/lockdep.c:5244) 
[ 35.965725][ C0] ? __pfx___dev_queue_xmit (net/core/dev.c:4281) 
[ 35.965905][ C0] ? __lock_release (kernel/locking/lockdep.c:5430) 
[ 35.966085][ C0] ? __pfx___lock_release (kernel/locking/lockdep.c:5406) 
[ 35.966383][ C0] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 35.966578][ C0] br_dev_queue_push_xmit (net/bridge/br_forward.c:34) bridge
[ 35.966846][ C0] ? __pfx_br_dev_queue_push_xmit (net/bridge/br_forward.c:34) bridge
[ 35.967126][ C0] ? __br_forward (./include/linux/netfilter.h:314 ./include/linux/netfilter.h:308 net/bridge/br_forward.c:115) bridge
[ 35.967499][ C0] deliver_clone (net/bridge/br_forward.c:132) bridge
[ 35.967725][ C0] br_handle_frame_finish (net/bridge/br_input.c:215) bridge
[ 35.968051][ C0] ? __pfx_br_handle_frame_finish (net/bridge/br_input.c:75) bridge
[ 35.968461][ C0] ? is_bpf_text_address (kernel/bpf/core.c:772) 
[ 35.968661][ C0] ? clear_bss (arch/x86/kernel/head64.c:384) 
[ 35.968811][ C0] ? common_startup_64 (arch/x86/kernel/head_64.S:421) 
[ 35.969010][ C0] ? schedule_on_each_cpu (kernel/workqueue.c:4226 (discriminator 3) kernel/workqueue.c:4419 (discriminator 3)) 
[ 35.969206][ C0] ? __pfx_stack_trace_consume_entry (kernel/stacktrace.c:83) 
[ 35.969548][ C0] ? arch_stack_walk (arch/x86/kernel/stacktrace.c:24) 
[ 35.969729][ C0] br_handle_frame (net/bridge/br_input.c:417) bridge
[ 35.969941][ C0] ? __pfx_br_handle_frame (net/bridge/br_input.c:321) bridge
[ 35.970200][ C0] __netif_receive_skb_core.constprop.0 (net/core/dev.c:5498) 
[ 35.970551][ C0] ? mark_lock (kernel/locking/lockdep.c:4656 (discriminator 3)) 
[ 35.970686][ C0] ? __lock_acquire (kernel/locking/lockdep.c:5137) 
[ 35.970864][ C0] ? __pfx___netif_receive_skb_core.constprop.0 (net/core/dev.c:5391) 
[ 35.971086][ C0] ? lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5756) 
[ 35.971385][ C0] ? process_backlog (./include/linux/rcupdate.h:329 ./include/linux/rcupdate.h:781 net/core/dev.c:6046) 
[ 35.971564][ C0] __netif_receive_skb_one_core (net/core/dev.c:5603) 
[ 35.971839][ C0] ? __pfx___netif_receive_skb_one_core (net/core/dev.c:5597) 
[ 35.972213][ C0] ? process_backlog (./include/linux/rcupdate.h:329 ./include/linux/rcupdate.h:781 net/core/dev.c:6046) 
[ 35.972409][ C0] ? lock_acquire (kernel/locking/lockdep.c:5727) 
[ 35.972587][ C0] ? process_backlog (./include/linux/rcupdate.h:329 ./include/linux/rcupdate.h:781 net/core/dev.c:6046) 
[ 35.972764][ C0] process_backlog (./include/linux/rcupdate.h:810 net/core/dev.c:6048) 
[ 35.972943][ C0] ? find_held_lock (kernel/locking/lockdep.c:5244) 
[ 35.973257][ C0] __napi_poll.constprop.0 (net/core/dev.c:6701) 
[ 35.973436][ C0] net_rx_action (net/core/dev.c:6770 net/core/dev.c:6886) 
[ 35.973616][ C0] ? __pfx_net_rx_action (net/core/dev.c:6850) 
[ 35.973797][ C0] ? usage_skip (kernel/locking/lockdep.c:2295 kernel/locking/lockdep.c:2263) 
[ 35.974103][ C0] ? mark_held_locks (kernel/locking/lockdep.c:4274) 
[ 35.974282][ C0] __do_softirq (kernel/softirq.c:554) 
[ 35.974463][ C0] ? __dev_queue_xmit (./include/linux/rcupdate.h:339 ./include/linux/rcupdate.h:849 net/core/dev.c:4399) 
[ 35.974640][ C0] do_softirq (kernel/softirq.c:455 kernel/softirq.c:442) 
[   35.974776][    C0]  </IRQ>
[   35.974867][    C0]  <TASK>
[ 35.974957][ C0] __local_bh_enable_ip (kernel/softirq.c:382) 
[ 35.975133][ C0] ? __dev_queue_xmit (./include/linux/rcupdate.h:339 ./include/linux/rcupdate.h:849 net/core/dev.c:4399) 
[ 35.975314][ C0] __dev_queue_xmit (net/core/dev.c:4400) 
[ 35.975495][ C0] ? mark_lock (kernel/locking/lockdep.c:4656 (discriminator 3)) 
[ 35.975629][ C0] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 52)) 
[ 35.975806][ C0] ? mark_held_locks (kernel/locking/lockdep.c:4274) 
[ 35.975983][ C0] ? eth_header (net/ethernet/eth.c:100) 
[ 35.976160][ C0] ? __pfx___dev_queue_xmit (net/core/dev.c:4281) 
[ 35.976462][ C0] ip6_finish_output2 (./include/net/neighbour.h:542 net/ipv6/ip6_output.c:137) 
[ 35.976640][ C0] ip6_finish_output (net/ipv6/ip6_output.c:211 net/ipv6/ip6_output.c:222) 
[ 35.976821][ C0] ? 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) 
[ 35.976999][ C0] ip6_output (./include/linux/netfilter.h:303 net/ipv6/ip6_output.c:243) 
[ 35.977133][ C0] ? __pfx_ip6_output (net/ipv6/ip6_output.c:230) 
[ 35.977430][ C0] ? lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 35.977611][ C0] NF_HOOK.constprop.0 (./include/linux/rcupdate.h:329 ./include/linux/rcupdate.h:781 ./include/linux/netfilter.h:238 ./include/linux/netfilter.h:312) 
[ 35.977789][ C0] ? ndisc_send_skb (./include/linux/rcupdate.h:339 ./include/linux/rcupdate.h:814 net/ipv6/ndisc.c:455 net/ipv6/ndisc.c:503) 
[ 35.977970][ C0] ? __pfx_NF_HOOK.constprop.0 (./include/linux/netfilter.h:308) 
[ 35.978267][ C0] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 35.978464][ C0] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 52)) 
[ 35.978643][ C0] ndisc_send_skb (net/ipv6/ndisc.c:512 (discriminator 60)) 
[ 35.978869][ C0] ? __pfx_ndisc_send_skb (net/ipv6/ndisc.c:473) 
[ 35.979202][ C0] ndisc_send_ns (net/ipv6/ndisc.c:653) 
[ 35.979405][ C0] ? mark_lock (kernel/locking/lockdep.c:4656 (discriminator 3)) 
[ 35.979543][ C0] ? __pfx_ndisc_send_ns (net/ipv6/ndisc.c:653) 
[ 35.979751][ C0] ? mark_held_locks (kernel/locking/lockdep.c:4274) 
[ 35.979930][ C0] ? lockdep_hardirqs_on_prepare.part.0 (kernel/locking/lockdep.c:4300 kernel/locking/lockdep.c:4359) 
[ 35.980327][ C0] addrconf_dad_work (net/ipv6/addrconf.c:4280) 
[ 35.980525][ C0] ? __pfx_addrconf_dad_work (net/ipv6/addrconf.c:4178) 
[ 35.980725][ C0] ? process_one_work (kernel/workqueue.c:3230) 
[ 35.980924][ C0] ? lock_acquire (kernel/locking/lockdep.c:5727) 
[ 35.981118][ C0] ? process_one_work (kernel/workqueue.c:3230) 
[ 35.981297][ C0] process_one_work (kernel/workqueue.c:3254) 
[ 35.981505][ C0] ? __pfx___lock_release (kernel/locking/lockdep.c:5406) 
[ 35.981684][ C0] ? __pfx_process_one_work (kernel/workqueue.c:3156) 
[ 35.981886][ C0] ? assign_work (kernel/workqueue.c:1209) 
[ 35.982084][ C0] worker_thread (kernel/workqueue.c:3329 kernel/workqueue.c:3416) 
[ 35.982264][ C0] ? __pfx_worker_thread (kernel/workqueue.c:3362) 
[ 35.982440][ C0] kthread (kernel/kthread.c:388) 
[ 35.982575][ C0] ? __pfx_kthread (kernel/kthread.c:341) 
[ 35.982753][ C0] ret_from_fork (arch/x86/kernel/process.c:147) 
[ 35.982931][ C0] ? __pfx_kthread (kernel/kthread.c:341) 


Finger prints:
ret_from_fork_asm:dump_stack_lvl:mark_lock_irq:mark_lock