======================================
| xx__-> echo $?
| 0
| xx__-> [   41.423214][    C1] BUG: spinlock bad magic on CPU#1, kworker/u16:0/11
| [ 41.423448][ C1] lock: noop_qdisc+0x240/0x300, .magic: 00000000, .owner: kworker/u16:0/11, .owner_cpu: 1 
[   41.423917][    C1] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[   41.424200][    C1] Workqueue: netns cleanup_net
[   41.424345][    C1] Call Trace:
[   41.424454][    C1]  <IRQ>
[ 41.424521][ C1] dump_stack_lvl (lib/dump_stack.c:122) 
[ 41.424680][ C1] do_raw_spin_unlock (kernel/locking/spinlock_debug.c:100 kernel/locking/spinlock_debug.c:141) 
[ 41.424812][ C1] _raw_spin_unlock (./arch/x86/include/asm/preempt.h:94 ./include/linux/spinlock_api_smp.h:143 kernel/locking/spinlock.c:186) 
[ 41.424975][ C1] 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) 
[ 41.425107][ C1] handle_softirqs (kernel/softirq.c:554) 
[ 41.425297][ C1] ? 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) 
[ 41.425431][ C1] do_softirq (kernel/softirq.c:455 kernel/softirq.c:442) 
[   41.425530][    C1]  </IRQ>
[   41.425595][    C1]  <TASK>


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