======================================
| [   29.115769][  T232] Cannot link a netdevsim to itself
| [   29.116561][  T232] Format for linking two devices is "netnsfd_a:ifidx_a netnsfd_b:ifidx_b" (int uint int uint).
| [   30.570554][    C1] BUG: spinlock bad magic on CPU#1, peer.sh/232
| [ 30.570988][ C1] lock: noop_qdisc+0x240/0x300, .magic: 00000000, .owner: peer.sh/232, .owner_cpu: 1 
[   30.571797][    C1] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[   30.572369][    C1] Call Trace:
[   30.572580][    C1]  <IRQ>
[ 30.572753][ C1] dump_stack_lvl (lib/dump_stack.c:122) 
[ 30.572997][ C1] do_raw_spin_unlock (kernel/locking/spinlock_debug.c:100 kernel/locking/spinlock_debug.c:141) 
[ 30.573240][ C1] _raw_spin_unlock (./arch/x86/include/asm/preempt.h:94 ./include/linux/spinlock_api_smp.h:143 kernel/locking/spinlock.c:186) 
[ 30.573468][ 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) 
[ 30.573714][ C1] handle_softirqs (kernel/softirq.c:554) 
[ 30.573958][ 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) 
[ 30.574199][ C1] do_softirq (kernel/softirq.c:455 kernel/softirq.c:442) 
[   30.574380][    C1]  </IRQ>
[   30.574508][    C1]  <TASK>
[ 30.574629][ C1] __local_bh_enable_ip (kernel/softirq.c:382) 
[ 30.574865][ C1] dev_deactivate_many (net/sched/sch_generic.c:1356) 
[ 30.575099][ C1] __dev_close_many (net/core/dev.c:1547) 
[ 30.575335][ C1] ? __pfx___dev_close_many (net/core/dev.c:1522) 
[ 30.575583][ C1] ? __pfx_validate_chain (kernel/locking/lockdep.c:3824) 
[ 30.575828][ C1] ? 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) 
[ 30.576075][ C1] dev_close_many (net/core/dev.c:1585) 
[ 30.576319][ C1] ? __lock_acquire (kernel/locking/lockdep.c:5142) 
[ 30.576500][ C1] ? __pfx_dev_close_many (net/core/dev.c:1575) 
[ 30.576654][ C1] unregister_netdevice_many_notify (net/core/dev.c:11321) 
[ 30.576841][ C1] ? nsim_destroy (drivers/net/netdevsim/netdev.c:774) netdevsim
[ 30.577004][ C1] ? __mutex_trylock_common (./arch/x86/include/asm/atomic64_64.h:101 ./include/linux/atomic/atomic-arch-fallback.h:4296 ./include/linux/atomic/atomic-long.h:1482 ./include/linux/atomic/atomic-instrumented.h:4458 kernel/locking/mutex.c:129) 
[ 30.577162][ C1] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11288) 
[ 30.577350][ C1] ? __pfx___mutex_trylock_common (kernel/locking/mutex.c:104) 
[ 30.577561][ C1] ? nsim_destroy (drivers/net/netdevsim/netdev.c:774) netdevsim
[ 30.577720][ C1] ? trace_contention_end (./include/trace/events/lock.h:122 (discriminator 52)) 
[ 30.577869][ C1] ? __mutex_lock (./arch/x86/include/asm/preempt.h:94 kernel/locking/mutex.c:618 kernel/locking/mutex.c:752) 
[ 30.578033][ C1] ? mntput_no_expire (fs/namespace.c:220 fs/namespace.c:1430) 
[ 30.578198][ C1] ? nsim_destroy (drivers/net/netdevsim/netdev.c:774) netdevsim
[ 30.578358][ C1] unregister_netdevice_queue (net/core/dev.c:11283) 
[ 30.578509][ C1] ? __pfx_do_raw_spin_lock (kernel/locking/spinlock_debug.c:114) 
[ 30.578662][ C1] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11272) 
[ 30.578855][ C1] nsim_destroy (drivers/net/netdevsim/netdev.c:779 (discriminator 2)) netdevsim
[ 30.579037][ C1] __nsim_dev_port_del (drivers/net/netdevsim/dev.c:426 drivers/net/netdevsim/dev.c:1426) netdevsim
[ 30.579236][ C1] nsim_dev_reload_destroy (drivers/net/netdevsim/dev.c:1435 drivers/net/netdevsim/dev.c:1658) netdevsim
[ 30.579429][ C1] nsim_drv_remove (drivers/net/netdevsim/dev.c:1675) netdevsim
[ 30.579588][ C1] device_release_driver_internal (drivers/base/dd.c:1274 drivers/base/dd.c:1295) 
[ 30.579771][ C1] ? klist_put (lib/klist.c:220) 
[ 30.579887][ C1] bus_remove_device (./include/linux/kobject.h:193 drivers/base/base.h:73 drivers/base/bus.c:581) 
[ 30.580039][ C1] device_del (drivers/base/core.c:3869) 
[ 30.580158][ C1] ? __pfx_device_del (drivers/base/core.c:3823) 
[ 30.580308][ C1] ? lock_acquire.part.0 (kernel/locking/lockdep.c:466 kernel/locking/lockdep.c:5761) 
[ 30.580454][ C1] ? kernfs_fop_write_iter (fs/kernfs/file.c:326) 
[ 30.580605][ C1] device_unregister (drivers/base/core.c:3786 drivers/base/core.c:3910) 
[ 30.580754][ C1] del_device_store (drivers/net/netdevsim/bus.c:230) netdevsim
[ 30.580949][ C1] ? __pfx_del_device_store (drivers/net/netdevsim/bus.c:197) netdevsim
[ 30.581146][ C1] ? __pfx_sysfs_kf_write (fs/sysfs/file.c:129) 
[ 30.581301][ C1] ? sysfs_file_ops (fs/sysfs/file.c:31 (discriminator 1)) 
[ 30.581450][ C1] ? __pfx_sysfs_kf_write (fs/sysfs/file.c:129) 
[ 30.581599][ C1] kernfs_fop_write_iter (fs/kernfs/file.c:334) 
[ 30.581750][ C1] vfs_write (fs/read_write.c:497 fs/read_write.c:590) 
[ 30.581867][ C1] ? __pfx_vfs_write (fs/read_write.c:571) 
[ 30.582017][ C1] ? find_held_lock (kernel/locking/lockdep.c:5249) 
[ 30.582177][ C1] ? __fget_light (./include/linux/atomic/atomic-arch-fallback.h:479 ./include/linux/atomic/atomic-instrumented.h:50 fs/file.c:1145) 
[ 30.582331][ C1] ksys_write (fs/read_write.c:643) 
[ 30.582444][ C1] ? __pfx_ksys_write (fs/read_write.c:633) 
[ 30.582602][ C1] do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) 
[ 30.582752][ C1] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) 
[   30.582936][    C1] RIP: 0033:0x7f3681377957
[ 30.583091][ C1] Code: 0b 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24
All code
========
   0:	0b 00                	or     (%rax),%eax
   2:	f7 d8                	neg    %eax
   4:	64 89 02             	mov    %eax,%fs:(%rdx)
   7:	48 c7 c0 ff ff ff ff 	mov    $0xffffffffffffffff,%rax
   e:	eb b7                	jmp    0xffffffffffffffc7
  10:	0f 1f 00             	nopl   (%rax)
  13:	f3 0f 1e fa          	endbr64
  17:	64 8b 04 25 18 00 00 	mov    %fs:0x18,%eax
  1e:	00 
  1f:	85 c0                	test   %eax,%eax
  21:	75 10                	jne    0x33
  23:	b8 01 00 00 00       	mov    $0x1,%eax
  28:	0f 05                	syscall
  2a:*	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax		<-- trapping instruction
  30:	77 51                	ja     0x83
  32:	c3                   	ret
  33:	48 83 ec 28          	sub    $0x28,%rsp
  37:	48 89 54 24 18       	mov    %rdx,0x18(%rsp)
  3c:	48                   	rex.W
  3d:	89                   	.byte 0x89
  3e:	74 24                	je     0x64

Code starting with the faulting instruction
===========================================
   0:	48 3d 00 f0 ff ff    	cmp    $0xfffffffffffff000,%rax
   6:	77 51                	ja     0x59
   8:	c3                   	ret
   9:	48 83 ec 28          	sub    $0x28,%rsp
   d:	48 89 54 24 18       	mov    %rdx,0x18(%rsp)
  12:	48                   	rex.W
  13:	89                   	.byte 0x89
  14:	74 24                	je     0x3a
[   30.583827][    C1] RSP: 002b:00007fff0d86f688 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[   30.584056][    C1] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f3681377957
[   30.584289][    C1] RDX: 0000000000000004 RSI: 0000564e46f99790 RDI: 0000000000000001
[   30.584513][    C1] RBP: 0000564e46f99790 R08: 0000000000000000 R09: 00007f36813ea4e0
[   30.584732][    C1] R10: 00007f36813ea3e0 R11: 0000000000000246 R12: 0000000000000004


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