======================================
| [ 356.895953][ T69] #3: ffffffffb35f1088 (rtnl_mutex){+.+.}-{4:4}, at: cleanup_net (net/core/net_namespace.c:639)
| [ 356.896344][ T69] #4: ffffffffb35dfc30 ((netdev_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
| [  356.896791][   T69]
| [  356.896791][   T69] stack backtrace:
[  356.897436][   T69] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  356.897712][   T69] Workqueue: netns cleanup_net
[  356.897959][   T69] Call Trace:
[  356.898128][   T69]  <TASK>
[ 356.898244][ T69] dump_stack_lvl (lib/dump_stack.c:123)
[ 356.898480][ T69] print_deadlock_bug (kernel/locking/lockdep.c:3040)
[ 356.898699][ T69] validate_chain (kernel/locking/lockdep.c:3894)
[ 356.898909][ T69] ? process_one_work (kernel/workqueue.c:3229)
[ 356.899124][ T69] ? __pfx_validate_chain (kernel/locking/lockdep.c:3860)
[ 356.899341][ T69] ? 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)
[ 356.899569][ T69] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 356.899739][ T69] __lock_acquire (kernel/locking/lockdep.c:5226)
[ 356.899965][ T69] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5851)
[ 356.900180][ T69] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 356.900451][ T69] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 356.900611][ T69] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 356.900819][ T69] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[ 356.901029][ T69] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 356.901244][ T69] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 356.901508][ T69] down_read (./arch/x86/include/asm/preempt.h:79 kernel/locking/rwsem.c:1246 kernel/locking/rwsem.c:1261 kernel/locking/rwsem.c:1526)
[ 356.901669][ T69] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 356.901918][ T69] ? __pfx_down_read (kernel/locking/rwsem.c:1522)
[ 356.902121][ T69] ? __pfx_netlink_broadcast_filtered (net/netlink/af_netlink.c:1505)
[ 356.902397][ T69] blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 356.902626][ T69] __netdev_upper_dev_unlink (net/core/dev.c:8000 (discriminator 11) net/core/dev.c:8017 (discriminator 11) net/core/dev.c:8167 (discriminator 11))
[ 356.902841][ T69] ? __pfx___netdev_upper_dev_unlink (net/core/dev.c:8151)
[ 356.903101][ T69] ? unregister_netdevice_queue (net/core/dev.c:11501)
[ 356.903364][ T69] ? __pfx_unregister_netdevice_queue (net/core/dev.c:11500)
[ 356.903625][ T69] ? __pfx_br_vlan_bridge_event (net/bridge/br_vlan.c:1739) bridge
[ 356.903950][ T69] netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 356.904165][ T69] ? __pfx_netdev_upper_dev_unlink (net/core/dev.c:8190)
[ 356.904425][ T69] macvlan_device_event (drivers/net/macvlan.c:1829 (discriminator 3)) macvlan
[ 356.904689][ T69] ? br_device_event (net/bridge/br.c:40) bridge
[ 356.904952][ T69] ? __pfx_macvlan_device_event (drivers/net/macvlan.c:1779) macvlan
[ 356.905222][ T69] ? nft_offload_netdev_event (net/netfilter/nf_tables_offload.c:677) nf_tables
[ 356.905550][ T69] notifier_call_chain (kernel/notifier.c:85 (discriminator 2))
[ 356.905781][ T69] blocking_notifier_call_chain (kernel/notifier.c:381 kernel/notifier.c:368)
[ 356.906012][ T69] unregister_netdevice_many_notify (net/core/dev.c:11575)
[ 356.906294][ T69] ? mark_held_locks (kernel/locking/lockdep.c:4321)
[ 356.906521][ T69] ? __pfx_unregister_netdevice_many_notify (net/core/dev.c:11516)
[ 356.906779][ T69] ? 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.h:47 kernel/locking/mutex.c:66)
[ 356.906986][ T69] ? rtnl_is_locked (net/core/rtnetlink.c:163)
[ 356.907202][ T69] ? 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.h:47 kernel/locking/mutex.c:66)
[ 356.907408][ T69] ? nexthop_net_exit_batch_rtnl (net/ipv4/nexthop.c:585 net/ipv4/nexthop.c:2158 net/ipv4/nexthop.c:2666 net/ipv4/nexthop.c:4010)
[ 356.907678][ T69] cleanup_net (net/core/net_namespace.c:644)
[ 356.907898][ T69] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 356.908117][ T69] ? __pfx_cleanup_net (net/core/net_namespace.c:592)
[ 356.908337][ T69] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[ 356.908572][ T69] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 356.908787][ T69] ? process_one_work (kernel/workqueue.c:3205)
[ 356.909010][ T69] process_one_work (kernel/workqueue.c:3229)
[ 356.909232][ T69] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 356.909440][ T69] ? __pfx_process_one_work (kernel/workqueue.c:3131)
[ 356.909658][ T69] ? assign_work (kernel/workqueue.c:1200)
[ 356.909877][ T69] worker_thread (kernel/workqueue.c:3304 kernel/workqueue.c:3391)
[ 356.910092][ T69] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking/lockdep.c:4406)
[ 356.910370][ T69] ? __pfx_worker_thread (kernel/workqueue.c:3337)
[ 356.910598][ T69] ? __pfx_worker_thread (kernel/workqueue.c:3337)
[ 356.910976][ T69] kthread (kernel/kthread.c:389)
[ 356.911144][ T69] ? __pfx_kthread (kernel/kthread.c:342)
[ 356.911363][ T69] ret_from_fork (arch/x86/kernel/process.c:147)
[ 356.911581][ T69] ? __pfx_kthread (kernel/kthread.c:342)


Finger prints:
print_deadlock_bug:validate_chain:__lock_acquire:down_read:blocking_notifier_call_chain