======================================
| [ 35.936048][ C0] ret_from_fork_asm (arch/x86/entry/entry_64.S:256) 
| [   35.936364][    C0]
| [   35.936462][    C0]
| [   35.936462][    C0] stack backtrace:
[   35.936962][    C0] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[   35.937374][    C0] Workqueue: ipv6_addrconf addrconf_dad_work
[   35.937730][    C0] Call Trace:
[   35.937872][    C0]  <IRQ>
[ 35.937966][ C0] dump_stack_lvl (lib/dump_stack.c:117) 
[ 35.938185][ C0] print_irq_inversion_bug.part.0 (kernel/locking/lockdep.c:4024) 
[ 35.938414][ C0] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:256) 
[ 35.938728][ C0] ? __pfx_print_irq_inversion_bug.part.0 (kernel/locking/lockdep.c:4024) 
[ 35.938955][ C0] ? __pfx_usage_skip (kernel/locking/lockdep.c:2264) 
[ 35.939143][ C0] ? __pfx_usage_match (kernel/locking/lockdep.c:2256) 
[ 35.939339][ C0] ? arch_stack_walk (arch/x86/kernel/stacktrace.c:24) 
[ 35.939649][ C0] mark_lock_irq (kernel/locking/lockdep.c:4244) 
[ 35.939835][ C0] ? __pfx_mark_lock_irq (kernel/locking/lockdep.c:4207) 
[ 35.940014][ C0] ? stack_trace_save (kernel/stacktrace.c:123) 
[ 35.940195][ C0] ? save_trace (kernel/locking/lockdep.c:586) 
[ 35.940502][ C0] mark_lock (kernel/locking/lockdep.c:4678) 
[ 35.940642][ C0] mark_usage (kernel/locking/lockdep.c:4567) 
[ 35.940781][ C0] __lock_acquire (kernel/locking/lockdep.c:5091) 
[ 35.940966][ C0] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5756) 
[ 35.941152][ C0] ? ipv6_get_lladdr (net/ipv6/addrconf.c:1911 net/ipv6/addrconf.c:1934) 
[ 35.941457][ C0] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 35.941639][ C0] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 52)) 
[ 35.941826][ C0] ? ipv6_get_lladdr (net/ipv6/addrconf.c:1911 net/ipv6/addrconf.c:1934) 
[ 35.942011][ C0] ? lock_acquire (kernel/locking/lockdep.c:5727) 
[ 35.942312][ C0] ? ipv6_get_lladdr (net/ipv6/addrconf.c:1911 net/ipv6/addrconf.c:1934) 
[ 35.942509][ C0] _raw_read_lock_bh (./include/linux/rwlock_api_smp.h:177 kernel/locking/spinlock.c:252) 
[ 35.942693][ C0] ? ipv6_get_lladdr (net/ipv6/addrconf.c:1911 net/ipv6/addrconf.c:1934) 
[ 35.942872][ C0] ipv6_get_lladdr (net/ipv6/addrconf.c:1911 net/ipv6/addrconf.c:1934) 
[ 35.943074][ C0] ndisc_send_ns (net/ipv6/ndisc.c:658) 
[ 35.943506][ C0] ? __pfx_ndisc_send_ns (net/ipv6/ndisc.c:653) 
[ 35.943699][ C0] ? __ipv6_chk_addr_and_flags (net/ipv6/addrconf.c:2009) 
[ 35.943944][ C0] ndisc_solicit (net/ipv6/ndisc.c:736) 
[ 35.944139][ C0] ? __pfx_ndisc_solicit (net/ipv6/ndisc.c:736) 
[ 35.944448][ C0] ? neigh_probe (net/core/neighbour.c:1074) 
[ 35.944640][ C0] neigh_probe (net/core/neighbour.c:1075) 
[ 35.944777][ C0] __neigh_event_send (net/core/neighbour.c:1242) 
[ 35.944961][ C0] neigh_resolve_output (net/core/neighbour.c:1547) 
[ 35.945268][ C0] ? __local_bh_enable_ip (./arch/x86/include/asm/irqflags.h:42 ./arch/x86/include/asm/irqflags.h:77 kernel/softirq.c:387) 
[ 35.945453][ C0] ? ___neigh_create (net/core/neighbour.c:722 (discriminator 9)) 
[ 35.945658][ C0] ip6_finish_output2 (./include/net/neighbour.h:542 net/ipv6/ip6_output.c:137) 
[ 35.945878][ C0] ip6_finish_output (net/ipv6/ip6_output.c:211 net/ipv6/ip6_output.c:222) 
[ 35.946072][ C0] ip6_output (./include/linux/netfilter.h:303 net/ipv6/ip6_output.c:243) 
[ 35.946225][ C0] ? __pfx_ip6_output (net/ipv6/ip6_output.c:230) 
[ 35.946405][ 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) 
[ 35.946605][ C0] ? ip6_mtu (./include/linux/rcupdate.h:339 ./include/linux/rcupdate.h:814 ./include/net/ip6_route.h:336 net/ipv6/route.c:3217) 
[ 35.946744][ C0] ? ip6_local_out (net/ipv6/output_core.c:154) 
[ 35.947077][ C0] udp_tunnel6_xmit_skb (./include/net/ip6_tunnel.h:163 net/ipv6/ip6_udp_tunnel.c:111) ip6_udp_tunnel
[ 35.947308][ C0] vxlan_xmit_one (drivers/net/vxlan/vxlan_core.c:2551) vxlan
[ 35.947506][ C0] ? stack_access_ok (arch/x86/kernel/unwind_orc.c:396) 
[ 35.947689][ C0] ? ip6_fraglist_init (./include/linux/skbuff.h:2711 net/ipv6/ip6_output.c:715) 
[ 35.947882][ C0] ? __pfx_vxlan_xmit_one (drivers/net/vxlan/vxlan_core.c:2313) vxlan
[ 35.948120][ C0] ? __lock_acquire (kernel/locking/lockdep.c:5137) 
[ 35.948312][ C0] ? orc_sort_cmp (arch/x86/kernel/unwind_orc.c:80 arch/x86/kernel/unwind_orc.c:271) 
[ 35.948506][ C0] ? __dev_queue_xmit (./include/linux/bottom_half.h:20 ./include/linux/rcupdate.h:833 net/core/dev.c:4297) 
[ 35.948693][ C0] ? lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5756) 
[ 35.948876][ C0] ? vxlan_xmit (drivers/net/vxlan/vxlan_core.c:2766) vxlan
[ 35.949071][ C0] vxlan_xmit (drivers/net/vxlan/vxlan_core.c:2766) vxlan
[ 35.949290][ 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) 
[ 35.949491][ C0] ? validate_xmit_skb.constprop.0 (net/core/dev.c:3634) 
[ 35.949719][ C0] __dev_queue_xmit (net/core/dev.h:167 net/core/dev.c:4373) 
[ 35.949935][ C0] ? find_held_lock (kernel/locking/lockdep.c:5244) 
[ 35.950128][ C0] ? __pfx___dev_queue_xmit (net/core/dev.c:4281) 
[ 35.950445][ C0] ? __lock_release (kernel/locking/lockdep.c:5430) 
[ 35.950640][ C0] ? __pfx___lock_release (kernel/locking/lockdep.c:5406) 
[ 35.950830][ C0] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 35.951037][ C0] br_dev_queue_push_xmit (net/bridge/br_forward.c:34) bridge
[ 35.951464][ C0] ? __pfx_br_dev_queue_push_xmit (net/bridge/br_forward.c:34) bridge
[ 35.951722][ C0] ? __br_forward (./include/linux/netfilter.h:314 ./include/linux/netfilter.h:308 net/bridge/br_forward.c:115) bridge
[ 35.951940][ C0] deliver_clone (net/bridge/br_forward.c:132) bridge
[ 35.952155][ C0] br_handle_frame_finish (net/bridge/br_input.c:215) bridge
[ 35.952540][ C0] ? __pfx_br_handle_frame_finish (net/bridge/br_input.c:75) bridge
[ 35.952803][ 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) 
[ 35.952983][ C0] ? mark_lock (kernel/locking/lockdep.c:4656 (discriminator 3)) 
[ 35.953127][ C0] br_handle_frame (net/bridge/br_input.c:417) bridge
[ 35.953466][ C0] ? __pfx_br_handle_frame (net/bridge/br_input.c:321) bridge
[ 35.953729][ C0] __netif_receive_skb_core.constprop.0 (net/core/dev.c:5498) 
[ 35.953967][ C0] ? mark_lock (kernel/locking/lockdep.c:4656 (discriminator 3)) 
[ 35.954104][ C0] ? __lock_acquire (kernel/locking/lockdep.c:5137) 
[ 35.954413][ C0] ? __pfx___netif_receive_skb_core.constprop.0 (net/core/dev.c:5391) 
[ 35.954641][ C0] ? lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5756) 
[ 35.954828][ C0] ? process_backlog (./include/linux/rcupdate.h:329 ./include/linux/rcupdate.h:781 net/core/dev.c:6046) 
[ 35.955007][ C0] __netif_receive_skb_one_core (net/core/dev.c:5603) 
[ 35.955349][ C0] ? __pfx___netif_receive_skb_one_core (net/core/dev.c:5597) 
[ 35.955595][ C0] ? process_backlog (./include/linux/rcupdate.h:329 ./include/linux/rcupdate.h:781 net/core/dev.c:6046) 
[ 35.955772][ C0] ? lock_acquire (kernel/locking/lockdep.c:5727) 
[ 35.955949][ C0] ? process_backlog (./include/linux/rcupdate.h:329 ./include/linux/rcupdate.h:781 net/core/dev.c:6046) 
[ 35.956263][ C0] process_backlog (./include/linux/rcupdate.h:810 net/core/dev.c:6048) 
[ 35.956456][ C0] __napi_poll.constprop.0 (net/core/dev.c:6701) 
[ 35.956664][ C0] net_rx_action (net/core/dev.c:6770 net/core/dev.c:6886) 
[ 35.956870][ C0] ? __pfx_net_rx_action (net/core/dev.c:6850) 
[ 35.957193][ C0] ? usage_skip (kernel/locking/lockdep.c:2295 kernel/locking/lockdep.c:2263) 
[ 35.957397][ C0] ? mark_held_locks (kernel/locking/lockdep.c:4274) 
[ 35.957613][ C0] __do_softirq (kernel/softirq.c:554) 
[ 35.957795][ C0] ? __dev_queue_xmit (./include/linux/rcupdate.h:339 ./include/linux/rcupdate.h:849 net/core/dev.c:4399) 
[ 35.957996][ C0] do_softirq (kernel/softirq.c:455 kernel/softirq.c:442) 
[   35.958291][    C0]  </IRQ>
[   35.958385][    C0]  <TASK>
[ 35.958487][ C0] __local_bh_enable_ip (kernel/softirq.c:382) 
[ 35.958669][ C0] ? __dev_queue_xmit (./include/linux/rcupdate.h:339 ./include/linux/rcupdate.h:849 net/core/dev.c:4399) 
[ 35.958853][ C0] __dev_queue_xmit (net/core/dev.c:4400) 
[ 35.959036][ C0] ? mark_lock (kernel/locking/lockdep.c:4656 (discriminator 3)) 
[ 35.959172][ C0] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 52)) 
[ 35.959370][ C0] ? mark_held_locks (kernel/locking/lockdep.c:4274) 
[ 35.959553][ C0] ? eth_header (net/ethernet/eth.c:100) 
[ 35.959737][ C0] ? __pfx___dev_queue_xmit (net/core/dev.c:4281) 
[ 35.959925][ C0] ip6_finish_output2 (./include/net/neighbour.h:542 net/ipv6/ip6_output.c:137) 
[ 35.960117][ C0] ip6_finish_output (net/ipv6/ip6_output.c:211 net/ipv6/ip6_output.c:222) 
[ 35.960302][ 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) 
[ 35.960483][ C0] ip6_output (./include/linux/netfilter.h:303 net/ipv6/ip6_output.c:243) 
[ 35.960628][ C0] ? __pfx_ip6_output (net/ipv6/ip6_output.c:230) 
[ 35.960809][ C0] ? lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 35.960993][ 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) 
[ 35.961180][ C0] ? ndisc_send_skb (./include/linux/rcupdate.h:339 ./include/linux/rcupdate.h:814 net/ipv6/ndisc.c:455 net/ipv6/ndisc.c:503) 
[ 35.961363][ C0] ? __pfx_NF_HOOK.constprop.0 (./include/linux/netfilter.h:308) 
[ 35.961555][ C0] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 35.961736][ C0] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 52)) 
[ 35.961923][ C0] ndisc_send_skb (net/ipv6/ndisc.c:512 (discriminator 60)) 
[ 35.962110][ C0] ? __pfx_ndisc_send_skb (net/ipv6/ndisc.c:473) 
[ 35.962305][ C0] ndisc_send_ns (net/ipv6/ndisc.c:653) 
[ 35.962511][ C0] ? mark_lock (kernel/locking/lockdep.c:4656 (discriminator 3)) 
[ 35.962656][ C0] ? __pfx_ndisc_send_ns (net/ipv6/ndisc.c:653) 
[ 35.962848][ C0] ? mark_held_locks (kernel/locking/lockdep.c:4274) 
[ 35.963041][ C0] ? lockdep_hardirqs_on_prepare.part.0 (kernel/locking/lockdep.c:4300 kernel/locking/lockdep.c:4359) 
[ 35.963267][ C0] addrconf_dad_work (net/ipv6/addrconf.c:4280) 
[ 35.963446][ C0] ? __pfx_addrconf_dad_work (net/ipv6/addrconf.c:4178) 
[ 35.963642][ C0] ? process_one_work (kernel/workqueue.c:3230) 
[ 35.963839][ C0] ? lock_acquire (kernel/locking/lockdep.c:5727) 
[ 35.964027][ C0] ? process_one_work (kernel/workqueue.c:3230) 
[ 35.964220][ C0] process_one_work (kernel/workqueue.c:3254) 
[ 35.964414][ C0] ? __pfx___lock_release (kernel/locking/lockdep.c:5406) 
[ 35.964606][ C0] ? __pfx_process_one_work (kernel/workqueue.c:3156) 
[ 35.964789][ C0] ? assign_work (kernel/workqueue.c:1209) 
[ 35.964970][ C0] worker_thread (kernel/workqueue.c:3329 kernel/workqueue.c:3416) 
[ 35.965156][ C0] ? __pfx_worker_thread (kernel/workqueue.c:3362) 
[ 35.965341][ C0] kthread (kernel/kthread.c:388) 
[ 35.965480][ C0] ? __pfx_kthread (kernel/kthread.c:341) 
[ 35.965659][ C0] ret_from_fork (arch/x86/kernel/process.c:147) 
[ 35.965852][ C0] ? __pfx_kthread (kernel/kthread.c:341) 


Finger prints:
ret_from_fork_asm:dump_stack_lvl:mark_lock_irq:mark_lock