======================================
| xx__-> [   34.288144][  T273] ipip: IPv4 and MPLS over IPv4 tunneling driver
| [   35.084660][  T279] ip (279) used greatest stack depth: 23552 bytes left
| [   49.729322][    C0] BUG: spinlock bad magic on CPU#0, kworker/u16:0/11
| [ 49.729559][ C0] lock: noop_qdisc+0x240/0x300, .magic: 00000000, .owner: kworker/u16:0/11, .owner_cpu: 0 
[   49.730117][    C0] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[   49.730438][    C0] Workqueue: netns cleanup_net
[   49.730594][    C0] Call Trace:
[   49.730708][    C0]  <IRQ>
[ 49.730782][ C0] dump_stack_lvl (lib/dump_stack.c:122) 
[ 49.730930][ C0] do_raw_spin_unlock (kernel/locking/spinlock_debug.c:100 kernel/locking/spinlock_debug.c:141) 
[ 49.731067][ C0] _raw_spin_unlock (./arch/x86/include/asm/preempt.h:94 ./include/linux/spinlock_api_smp.h:143 kernel/locking/spinlock.c:186) 
[ 49.731210][ C0] 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) 
[ 49.731348][ C0] handle_softirqs (kernel/softirq.c:554) 
[ 49.731491][ C0] ? 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) 
[ 49.731637][ C0] do_softirq (kernel/softirq.c:455 kernel/softirq.c:442) 
[   49.731739][    C0]  </IRQ>
[   49.731807][    C0]  <TASK>
[ 49.731899][ C0] __local_bh_enable_ip (kernel/softirq.c:382) 
[ 49.732048][ C0] dev_deactivate_many (net/sched/sch_generic.c:1356) 
[ 49.732208][ C0] __dev_close_many (net/core/dev.c:1547) 
[ 49.732351][ C0] ? __pfx___dev_close_many (net/core/dev.c:1522) 
[ 49.732488][ C0] ? __pfx_validate_chain (kernel/locking/lockdep.c:3824) 
[ 49.732632][ 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:227) 
[ 49.732785][ C0] ? mark_lock (kernel/locking/lockdep.c:4655 (discriminator 3)) 
[ 49.732890][ C0] dev_close_many (net/core/dev.c:1585) 
[ 49.733037][ C0] ? __pfx_dev_close_many (net/core/dev.c:1575) 
[ 49.733179][ C0] unregister_netdevice_many_notify (net/core/dev.c:11321) 
[ 49.733375][ C0] ? net_generic (./include/linux/rcupdate.h:336 ./include/linux/rcupdate.h:869 ./include/net/netns/generic.h:48) 
[ 49.733529][ C0] ? __pfx___lock_release (kernel/locking/lockdep.c:5411) 
[ 49.733670][ C0] ? rtnl_is_locked (net/core/rtnetlink.c:164) 
[ 49.733815][ C0] ? unregister_netdevice_queue (net/core/dev.c:11273) 
[ 49.733992][ C0] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11288) 
[ 49.734170][ C0] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11272) 
[ 49.734343][ C0] ? net_generic (./include/linux/rcupdate.h:336 ./include/linux/rcupdate.h:869 ./include/net/netns/generic.h:48) 
[ 49.734491][ C0] ? lockdep_rtnl_is_held (net/core/rtnetlink.c:177) 
[ 49.734635][ C0] ? sit_destroy_tunnels (net/ipv6/sit.c:1818 (discriminator 1)) 
[ 49.734784][ C0] ? mutex_is_locked (./arch/x86/include/asm/atomic64_64.h:15 ./include/linux/atomic/atomic-arch-fallback.h:2583 ./include/linux/atomic/atomic-long.h:38 ./include/linux/atomic/atomic-instrumented.h:3189 kernel/locking/mutex.c:81 kernel/locking/mutex.c:91) 
[ 49.734922][ C0] ? nexthop_net_exit_batch_rtnl (net/ipv4/nexthop.c:585 net/ipv4/nexthop.c:2146 net/ipv4/nexthop.c:2654 net/ipv4/nexthop.c:4004) 
[ 49.735097][ C0] cleanup_net (net/core/net_namespace.c:622) 
[ 49.735236][ C0] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5724) 
[ 49.735382][ C0] ? __pfx_cleanup_net (net/core/net_namespace.c:570) 
[ 49.735521][ C0] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 52)) 
[ 49.735670][ C0] ? process_one_work (kernel/workqueue.c:3207) 
[ 49.735814][ C0] ? lock_acquire (kernel/locking/lockdep.c:5732) 
[ 49.735955][ C0] ? process_one_work (kernel/workqueue.c:3207) 
[ 49.736104][ C0] process_one_work (kernel/workqueue.c:3231) 
[ 49.736250][ C0] ? __pfx___lock_release (kernel/locking/lockdep.c:5411) 
[ 49.736392][ C0] ? __pfx_process_one_work (kernel/workqueue.c:3133) 
[ 49.736539][ C0] ? assign_work (kernel/workqueue.c:1202) 
[ 49.736682][ C0] worker_thread (kernel/workqueue.c:3306 kernel/workqueue.c:3390) 
[ 49.736830][ C0] ? __pfx_worker_thread (kernel/workqueue.c:3339) 
[ 49.736972][ C0] kthread (kernel/kthread.c:389) 
[ 49.737077][ C0] ? __pfx_kthread (kernel/kthread.c:342) 
[ 49.737218][ C0] ret_from_fork (arch/x86/kernel/process.c:147) 
[ 49.737374][ C0] ? __pfx_kthread (kernel/kthread.c:342) 


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