======================================
| [ 18.498561][ T40] #2: ffffffff939e7a48 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event (net/core/link_watch.c:282)
| [ 18.498820][ T40] #3: ffffffff939d6630 ((netdev_chain).rwsem){++++}-{4:4}, at: blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
| [   18.499111][   T40]
| [   18.499111][   T40] stack backtrace:
[   18.499545][   T40] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   18.499723][   T40] Workqueue: events_unbound linkwatch_event
[   18.499904][   T40] Call Trace:
[   18.500015][   T40]  <TASK>
[ 18.500093][ T40] dump_stack_lvl (lib/dump_stack.c:123)
[ 18.500251][ T40] print_circular_bug (kernel/locking/lockdep.c:2077)
[ 18.500443][ T40] check_noncircular (kernel/locking/lockdep.c:2206)
[ 18.500588][ T40] ? rcu_read_lock_any_held (kernel/rcu/update.c:386 kernel/rcu/update.c:380)
[ 18.500741][ T40] ? __bfs (kernel/locking/lockdep.c:1811 (discriminator 1))
[ 18.500851][ T40] ? __pfx_check_noncircular (kernel/locking/lockdep.c:2182)
[ 18.500994][ T40] ? check_irq_usage (kernel/locking/lockdep.c:2828)
[ 18.501139][ T40] ? alloc_chain_hlocks (kernel/locking/lockdep.c:3528)
[ 18.501286][ T40] ? __pfx_check_irq_usage (kernel/locking/lockdep.c:2813)
[ 18.501435][ T40] check_prev_add (kernel/locking/lockdep.c:3162)
[ 18.501583][ T40] validate_chain (kernel/locking/lockdep.c:3281 kernel/locking/lockdep.c:3904)
[ 18.501728][ T40] ? __pfx_validate_chain (kernel/locking/lockdep.c:3860)
[ 18.501880][ T40] ? 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)
[ 18.502022][ T40] ? mark_lock (kernel/locking/lockdep.c:4727 (discriminator 3))
[ 18.502131][ T40] __lock_acquire (kernel/locking/lockdep.c:5226)
[ 18.502275][ T40] ? check_prev_add (kernel/locking/lockdep.c:3180)
[ 18.502446][ T40] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5851)
[ 18.502591][ T40] ? team_port_change_check (drivers/net/team/team_core.c:2939 drivers/net/team/team_core.c:2962)
[ 18.502735][ T40] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5814)
[ 18.502877][ T40] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 37))
[ 18.503020][ T40] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 18.503162][ T40] ? team_port_change_check (drivers/net/team/team_core.c:2939 drivers/net/team/team_core.c:2962)
[ 18.503304][ T40] __mutex_lock (kernel/locking/mutex.c:587 kernel/locking/mutex.c:735)
[ 18.503453][ T40] ? team_port_change_check (drivers/net/team/team_core.c:2939 drivers/net/team/team_core.c:2962)
[ 18.503599][ T40] ? team_port_change_check (drivers/net/team/team_core.c:2939 drivers/net/team/team_core.c:2962)
[ 18.503741][ T40] ? __pfx___mutex_lock (kernel/locking/mutex.c:734)
[ 18.503884][ T40] ? lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5851)
[ 18.504027][ T40] ? blocking_notifier_call_chain (kernel/notifier.c:380 kernel/notifier.c:368)
[ 18.504205][ T40] ? find_held_lock (kernel/locking/lockdep.c:5339)
[ 18.504353][ T40] ? __pfx_fib_sync_up (net/ipv4/fib_semantics.c:2111)
[ 18.504504][ T40] ? __pfx_rwsem_read_trylock (kernel/locking/rwsem.c:249)
[ 18.504650][ T40] ? team_port_change_check (drivers/net/team/team_core.c:2939 drivers/net/team/team_core.c:2962)
[ 18.504794][ T40] team_port_change_check (drivers/net/team/team_core.c:2939 drivers/net/team/team_core.c:2962)
[ 18.504938][ T40] team_device_event (drivers/net/team/team_core.c:3017)
[ 18.505080][ T40] ? trace_notifier_run (./include/trace/events/notifier.h:59 (discriminator 37))
[ 18.505222][ T40] notifier_call_chain (kernel/notifier.c:85 (discriminator 2))
[ 18.505367][ T40] blocking_notifier_call_chain (kernel/notifier.c:381 kernel/notifier.c:368)
[ 18.505542][ T40] netdev_state_change (net/core/dev.c:1381 net/core/dev.c:1372)
[ 18.505686][ T40] ? __pfx_netdev_state_change (net/core/dev.c:1373)
[ 18.505831][ T40] linkwatch_do_dev (net/core/link_watch.c:182)
[ 18.505973][ T40] __linkwatch_run_queue (./include/linux/spinlock.h:376 net/core/link_watch.c:241)
[ 18.506116][ T40] ? __pfx___linkwatch_run_queue (net/core/link_watch.c:191)
[ 18.506292][ T40] ? lock_acquire (kernel/locking/lockdep.c:5822)
[ 18.506438][ T40] linkwatch_event (net/core/link_watch.c:283)
[ 18.506607][ T40] process_one_work (kernel/workqueue.c:3229)
[ 18.506752][ T40] ? __pfx___lock_release (kernel/locking/lockdep.c:5501)
[ 18.506895][ T40] ? __pfx_process_one_work (kernel/workqueue.c:3131)
[ 18.507038][ T40] ? assign_work (kernel/workqueue.c:1200)
[ 18.507184][ T40] worker_thread (kernel/workqueue.c:3304 kernel/workqueue.c:3391)
[ 18.507331][ T40] ? __pfx_worker_thread (kernel/workqueue.c:3337)
[ 18.507471][ T40] kthread (kernel/kthread.c:389)
[ 18.507581][ T40] ? __pfx_kthread (kernel/kthread.c:342)
[ 18.507734][ T40] ret_from_fork (arch/x86/kernel/process.c:147)
[ 18.507878][ T40] ? __pfx_kthread (kernel/kthread.c:342)


Finger prints:
print_circular_bug:check_noncircular:check_prev_add:validate_chain:__lock_acquire