======================================
| [ 31.262319][ T241] #1: ffffc90000a87d40 ((work_completion)(&port->wq)){+.+.}-{0:0}, at: process_one_work (kernel/workqueue.c:3214) 
| [ 31.262623][ T241] #2: ffffffffa2f5b5c0 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit (./include/linux/bottom_half.h:20 ./include/linux/rcupdate.h:901 net/core/dev.c:4555) 
| [   31.262907][  T241]
| [   31.262907][  T241] stack backtrace:
[   31.263098][  T241] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   31.263101][  T241] Workqueue: events ipvlan_process_multicast
[   31.263120][  T241] Call Trace:
[   31.263125][  T241]  <TASK>
[ 31.263129][ T241] dump_stack_lvl (lib/dump_stack.c:123) 
[ 31.263150][ T241] lockdep_rcu_suspicious (kernel/locking/lockdep.c:6848) 
[ 31.263168][ T241] dev_hard_start_xmit (./include/net/net_namespace.h:418 ./include/linux/netdevice.h:2695 net/core/dev.c:2466 net/core/dev.c:3772 net/core/dev.c:3793) 
[ 31.263179][ T241] __dev_queue_xmit (net/core/dev.h:340 net/core/dev.c:4631) 
[ 31.263195][ T241] ? __pfx___dev_queue_xmit (net/core/dev.c:4538) 
[ 31.263199][ T241] ? find_held_lock (kernel/locking/lockdep.c:5341) 
[ 31.263207][ T241] ? __lock_release (kernel/locking/lockdep.c:5527) 
[ 31.263209][ T241] ? ipvlan_process_multicast (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 drivers/net/ipvlan/ipvlan_core.c:284) 
[ 31.263214][ T241] ? __pfx___lock_release (kernel/locking/lockdep.c:5503) 
[ 31.263217][ T241] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5816) 
[ 31.263230][ T241] ? ipvlan_process_multicast (./include/linux/rcupdate.h:347 ./include/linux/rcupdate.h:880 drivers/net/ipvlan/ipvlan_core.c:284) 
[ 31.263238][ T241] ipvlan_process_multicast (./include/linux/netdevice.h:3331 drivers/net/ipvlan/ipvlan_core.c:290) 
[ 31.263254][ T241] ? __pfx_ipvlan_process_multicast (drivers/net/ipvlan/ipvlan_core.c:229) 
[ 31.263260][ T241] ? __pfx___lock_release (kernel/locking/lockdep.c:5503) 
[ 31.263264][ T241] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5816) 
[ 31.263269][ T241] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 21)) 
[ 31.263272][ T241] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 21)) 
[ 31.263279][ T241] ? lock_acquire (kernel/locking/lockdep.c:5824) 
[ 31.263287][ T241] ? process_one_work (kernel/workqueue.c:3238) 
[ 31.263291][ T241] ? process_one_work (kernel/workqueue.c:3214) 
[ 31.263293][ T241] process_one_work (kernel/workqueue.c:3238) 
[ 31.263308][ T241] ? __pfx___lock_release (kernel/locking/lockdep.c:5503) 
[ 31.263313][ T241] ? __pfx_process_one_work (kernel/workqueue.c:3140) 
[ 31.263326][ T241] ? assign_work (kernel/workqueue.c:1200) 
[ 31.263335][ T241] worker_thread (kernel/workqueue.c:3313 kernel/workqueue.c:3400) 
[ 31.263340][ T241] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4349 kernel/locking/lockdep.c:4408) 
[ 31.263351][ T241] ? __pfx_worker_thread (kernel/workqueue.c:3346) 
[ 31.263357][ T241] kthread (kernel/kthread.c:464) 
[ 31.263365][ T241] ? __pfx_kthread (kernel/kthread.c:413) 
[ 31.263375][ T241] ? __pfx_kthread (kernel/kthread.c:413) 
[ 31.263382][ T241] ret_from_fork (arch/x86/kernel/process.c:148) 
[ 31.263392][ T241] ? __pfx_kthread (kernel/kthread.c:413) 


Finger prints:
lockdep_rcu_suspicious:dev_hard_start_xmit:__dev_queue_xmit:ipvlan_process_multicast:process_one_work