======================================
| [ 144.768235][ T73] #2: ffffffffa0b9de50 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net (net/core/net_namespace.c:594) 
| [ 144.768454][ T73] #3: ffff888003e03958 (&hashinfo->ehash_locks[i]){+.-.}-{2:2}, at: inet_twsk_deschedule_put (net/ipv4/inet_timewait_sock.c:243) 
| [  144.768705][   T73]
| [  144.768705][   T73] stack backtrace:
[  144.769038][   T73] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[  144.769303][   T73] Workqueue: netns cleanup_net
[  144.769429][   T73] Call Trace:
[  144.769524][   T73]  <TASK>
[ 144.769595][ T73] dump_stack_lvl (lib/dump_stack.c:117) 
[ 144.769719][ T73] check_noncircular (kernel/locking/lockdep.c:2187) 
[ 144.769841][ T73] ? __pfx_check_noncircular (kernel/locking/lockdep.c:2163) 
[ 144.769965][ T73] ? __pfx_stack_trace_save (kernel/stacktrace.c:114) 
[ 144.770089][ T73] ? alloc_chain_hlocks (kernel/locking/lockdep.c:3501) 
[ 144.770214][ T73] check_prev_add (kernel/locking/lockdep.c:3135) 
[ 144.770337][ T73] validate_chain (kernel/locking/lockdep.c:3254 kernel/locking/lockdep.c:3869) 
[ 144.770460][ T73] ? __pfx_validate_chain (kernel/locking/lockdep.c:3825) 
[ 144.770579][ T73] ? 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) 
[ 144.770698][ T73] ? mark_lock (kernel/locking/lockdep.c:4656 (discriminator 3)) 
[ 144.770792][ T73] __lock_acquire (kernel/locking/lockdep.c:5137) 
[ 144.770913][ T73] ? __lock_acquire (kernel/locking/lockdep.c:5133) 
[ 144.771034][ T73] ? __timer_delete_sync (kernel/time/timer.c:1648 (discriminator 1)) 
[ 144.771155][ T73] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5756) 
[ 144.771279][ T73] ? __timer_delete_sync (kernel/time/timer.c:1648 (discriminator 1)) 
[ 144.771404][ T73] ? inet_twsk_deschedule_put (net/ipv4/inet_timewait_sock.c:243) 
[ 144.771525][ T73] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 144.771647][ T73] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 52)) 
[ 144.771767][ T73] ? __timer_delete_sync (kernel/time/timer.c:1648 (discriminator 1)) 
[ 144.771887][ T73] ? lock_acquire (kernel/locking/lockdep.c:5727) 
[ 144.772008][ T73] ? __timer_delete_sync (kernel/time/timer.c:1648 (discriminator 1)) 
[ 144.772130][ T73] __timer_delete_sync (kernel/time/timer.c:1649 (discriminator 1)) 
[ 144.772251][ T73] ? __timer_delete_sync (kernel/time/timer.c:1648 (discriminator 1)) 
[ 144.772372][ T73] inet_twsk_deschedule_put (net/ipv4/inet_timewait_sock.c:243) 
[ 144.772496][ T73] ? inet_twsk_purge (./include/linux/rcupdate.h:339 ./include/linux/rcupdate.h:814 net/ipv4/inet_timewait_sock.c:328) 
[ 144.772617][ T73] inet_twsk_purge (net/ipv4/inet_timewait_sock.c:331) 
[ 144.772737][ T73] ? inet_twsk_purge (./include/linux/rcupdate.h:329 ./include/linux/rcupdate.h:781 net/ipv4/inet_timewait_sock.c:308) 
[ 144.772861][ T73] ? __pfx_inet_twsk_purge (net/ipv4/inet_timewait_sock.c:295) 
[ 144.772985][ T73] ? mark_lock (kernel/locking/lockdep.c:4656 (discriminator 3)) 
[ 144.773080][ T73] tcp_twsk_purge (net/ipv4/tcp_minisocks.c:402) 
[ 144.773201][ T73] tcp_sk_exit_batch (net/ipv4/tcp_ipv4.c:3507) 
[ 144.773328][ T73] cleanup_net (net/core/net_namespace.c:636 (discriminator 3)) 
[ 144.773453][ T73] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 144.773580][ T73] ? __pfx_cleanup_net (net/core/net_namespace.c:581) 
[ 144.773703][ T73] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 52)) 
[ 144.773824][ T73] ? process_one_work (kernel/workqueue.c:3230) 
[ 144.773951][ T73] ? lock_acquire (kernel/locking/lockdep.c:5727) 
[ 144.774073][ T73] ? process_one_work (kernel/workqueue.c:3230) 
[ 144.774197][ T73] process_one_work (kernel/workqueue.c:3254) 
[ 144.774324][ T73] ? __pfx___lock_release (kernel/locking/lockdep.c:5406) 
[ 144.774451][ T73] ? __pfx_process_one_work (kernel/workqueue.c:3156) 
[ 144.774575][ T73] ? assign_work (kernel/workqueue.c:1209) 
[ 144.774697][ T73] worker_thread (kernel/workqueue.c:3329 kernel/workqueue.c:3416) 
[ 144.774818][ T73] ? lockdep_hardirqs_on_prepare.part.0 (kernel/locking/lockdep.c:4300 kernel/locking/lockdep.c:4359) 
[ 144.774969][ T73] ? __pfx_worker_thread (kernel/workqueue.c:3362) 
[ 144.775156][ T73] ? __pfx_worker_thread (kernel/workqueue.c:3362) 
[ 144.775283][ T73] kthread (kernel/kthread.c:388) 
[ 144.775379][ T73] ? __pfx_kthread (kernel/kthread.c:341) 
[ 144.775497][ T73] ret_from_fork (arch/x86/kernel/process.c:147) 
[ 144.775688][ T73] ? __pfx_kthread (kernel/kthread.c:341) 


Finger prints:
dump_stack_lvl:check_noncircular:check_prev_add:validate_chain