======================================
| 0
| xx__-> [   27.511090][  T243] ip (243) used greatest stack depth: 23824 bytes left
| [   27.799394][    C2] BUG: spinlock bad magic on CPU#2, kworker/2:1/51
| [ 27.799626][ C2] lock: noop_qdisc+0x240/0x300, .magic: 00000000, .owner: kworker/2:1/51, .owner_cpu: 2 
[   27.800138][    C2] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[   27.800449][    C2] Workqueue: events linkwatch_event
[   27.800603][    C2] Call Trace:
[   27.800705][    C2]  <IRQ>
[ 27.800774][ C2] dump_stack_lvl (lib/dump_stack.c:122) 
[ 27.800917][ C2] do_raw_spin_unlock (kernel/locking/spinlock_debug.c:100 kernel/locking/spinlock_debug.c:141) 
[ 27.801048][ C2] _raw_spin_unlock (./arch/x86/include/asm/preempt.h:94 ./include/linux/spinlock_api_smp.h:143 kernel/locking/spinlock.c:186) 
[ 27.801178][ C2] 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) 
[ 27.801313][ C2] handle_softirqs (kernel/softirq.c:554) 
[ 27.801444][ C2] ? 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) 
[ 27.801586][ C2] do_softirq (kernel/softirq.c:455 kernel/softirq.c:442) 
[   27.801687][    C2]  </IRQ>
[   27.801754][    C2]  <TASK>
[ 27.801819][ C2] __local_bh_enable_ip (kernel/softirq.c:382) 
[ 27.801958][ C2] dev_deactivate_many (net/sched/sch_generic.c:1356) 
[ 27.802086][ C2] ? __lock_release (kernel/locking/lockdep.c:5435) 
[ 27.802214][ C2] ? __linkwatch_run_queue (net/core/link_watch.c:234) 
[ 27.802351][ C2] dev_deactivate (./include/linux/list.h:111 ./include/linux/list.h:215 ./include/linux/list.h:229 net/sched/sch_generic.c:1398) 
[ 27.802493][ C2] ? __pfx_dev_deactivate (net/sched/sch_generic.c:1393) 
[ 27.802632][ C2] ? mark_held_locks (kernel/locking/lockdep.c:4273) 
[ 27.802778][ C2] linkwatch_do_dev (net/core/link_watch.c:177) 
[ 27.802922][ C2] __linkwatch_run_queue (./include/linux/spinlock.h:376 net/core/link_watch.c:236) 
[ 27.803084][ C2] ? __pfx___linkwatch_run_queue (net/core/link_watch.c:186) 
[ 27.803261][ C2] ? process_one_work (kernel/workqueue.c:3207) 
[ 27.803399][ C2] ? lock_acquire (kernel/locking/lockdep.c:5732) 
[ 27.803539][ C2] linkwatch_event (net/core/link_watch.c:278) 
[ 27.803686][ C2] process_one_work (kernel/workqueue.c:3231) 
[ 27.803813][ C2] ? __pfx___lock_release (kernel/locking/lockdep.c:5411) 
[ 27.803948][ C2] ? __pfx_process_one_work (kernel/workqueue.c:3133) 
[ 27.804076][ C2] ? assign_work (kernel/workqueue.c:1202) 
[ 27.804202][ C2] worker_thread (kernel/workqueue.c:3306 kernel/workqueue.c:3390) 
[ 27.804385][ C2] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4299 kernel/locking/lockdep.c:4358) 
[ 27.804550][ C2] ? __pfx_worker_thread (kernel/workqueue.c:3339) 
[ 27.804699][ C2] ? __pfx_worker_thread (kernel/workqueue.c:3339) 
[ 27.804829][ C2] kthread (kernel/kthread.c:389) 
[ 27.804960][ C2] ? __pfx_kthread (kernel/kthread.c:342) 
[ 27.805129][ C2] ret_from_fork (arch/x86/kernel/process.c:147) 
[ 27.805284][ C2] ? __pfx_kthread (kernel/kthread.c:342) 


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