======================================
| [ 516.511783][ T10] #2: ffffffff9799de50 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net (net/core/net_namespace.c:594) 
| [ 516.512002][ T10] #3: ffff888003c0b998 (&hashinfo->ehash_locks[i]){+.-.}-{2:2}, at: inet_twsk_deschedule_put (net/ipv4/inet_timewait_sock.c:243) 
| [  516.512319][   T10]
| [  516.512319][   T10] stack backtrace:
[  516.512656][   T10] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[  516.512923][   T10] Workqueue: netns cleanup_net
[  516.513052][   T10] Call Trace:
[  516.513212][   T10]  <TASK>
[ 516.513276][ T10] dump_stack_lvl (lib/dump_stack.c:117) 
[ 516.513400][ T10] check_noncircular (kernel/locking/lockdep.c:2187) 
[ 516.513521][ T10] ? __pfx_check_noncircular (kernel/locking/lockdep.c:2163) 
[ 516.513648][ T10] ? __pfx_stack_trace_save (kernel/stacktrace.c:114) 
[ 516.513837][ T10] ? alloc_chain_hlocks (kernel/locking/lockdep.c:3501) 
[ 516.513959][ T10] check_prev_add (kernel/locking/lockdep.c:3135) 
[ 516.514082][ T10] validate_chain (kernel/locking/lockdep.c:3254 kernel/locking/lockdep.c:3869) 
[ 516.514205][ T10] ? __pfx_validate_chain (kernel/locking/lockdep.c:3825) 
[ 516.514391][ T10] ? 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) 
[ 516.514512][ T10] ? mark_lock (kernel/locking/lockdep.c:4656 (discriminator 3)) 
[ 516.514604][ T10] __lock_acquire (kernel/locking/lockdep.c:5137) 
[ 516.514728][ T10] ? __lock_acquire (kernel/locking/lockdep.c:5133) 
[ 516.514851][ T10] ? __timer_delete_sync (kernel/time/timer.c:1648 (discriminator 1)) 
[ 516.515038][ T10] lock_acquire.part.0 (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5756) 
[ 516.515159][ T10] ? __timer_delete_sync (kernel/time/timer.c:1648 (discriminator 1)) 
[ 516.515279][ T10] ? inet_twsk_deschedule_put (net/ipv4/inet_timewait_sock.c:243) 
[ 516.515400][ T10] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 516.515651][ T10] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 52)) 
[ 516.515775][ T10] ? __timer_delete_sync (kernel/time/timer.c:1648 (discriminator 1)) 
[ 516.515895][ T10] ? lock_acquire (kernel/locking/lockdep.c:5727) 
[ 516.516020][ T10] ? __timer_delete_sync (kernel/time/timer.c:1648 (discriminator 1)) 
[ 516.516214][ T10] __timer_delete_sync (kernel/time/timer.c:1649 (discriminator 1)) 
[ 516.516334][ T10] ? __timer_delete_sync (kernel/time/timer.c:1648 (discriminator 1)) 
[ 516.516453][ T10] inet_twsk_deschedule_put (net/ipv4/inet_timewait_sock.c:243) 
[ 516.516572][ T10] ? inet_twsk_purge (./include/linux/rcupdate.h:339 ./include/linux/rcupdate.h:814 net/ipv4/inet_timewait_sock.c:328) 
[ 516.516692][ T10] inet_twsk_purge (net/ipv4/inet_timewait_sock.c:331) 
[ 516.516879][ T10] ? inet_twsk_purge (./include/linux/rcupdate.h:329 ./include/linux/rcupdate.h:781 net/ipv4/inet_timewait_sock.c:308) 
[ 516.516999][ T10] ? __pfx_inet_twsk_purge (net/ipv4/inet_timewait_sock.c:295) 
[ 516.517118][ T10] ? mark_lock (kernel/locking/lockdep.c:4656 (discriminator 3)) 
[ 516.517212][ T10] tcp_twsk_purge (net/ipv4/tcp_minisocks.c:402) 
[ 516.517399][ T10] tcp_sk_exit_batch (net/ipv4/tcp_ipv4.c:3507) 
[ 516.517520][ T10] cleanup_net (net/core/net_namespace.c:636 (discriminator 3)) 
[ 516.517640][ T10] ? __pfx_lock_acquire.part.0 (kernel/locking/lockdep.c:5719) 
[ 516.517762][ T10] ? __pfx_cleanup_net (net/core/net_namespace.c:581) 
[ 516.517947][ T10] ? trace_lock_acquire (./include/trace/events/lock.h:24 (discriminator 52)) 
[ 516.518071][ T10] ? process_one_work (kernel/workqueue.c:3230) 
[ 516.518192][ T10] ? lock_acquire (kernel/locking/lockdep.c:5727) 
[ 516.518313][ T10] ? process_one_work (kernel/workqueue.c:3230) 
[ 516.518435][ T10] process_one_work (kernel/workqueue.c:3254) 
[ 516.518621][ T10] ? __pfx___lock_release (kernel/locking/lockdep.c:5406) 
[ 516.518741][ T10] ? __pfx_process_one_work (kernel/workqueue.c:3156) 
[ 516.518865][ T10] ? assign_work (kernel/workqueue.c:1209) 
[ 516.518987][ T10] worker_thread (kernel/workqueue.c:3329 kernel/workqueue.c:3416) 
[ 516.519178][ T10] ? __pfx_worker_thread (kernel/workqueue.c:3362) 
[ 516.519299][ T10] kthread (kernel/kthread.c:388) 
[ 516.519392][ T10] ? __pfx_kthread (kernel/kthread.c:341) 
[ 516.519514][ T10] ret_from_fork (arch/x86/kernel/process.c:147) 
[ 516.519698][ T10] ? __pfx_kthread (kernel/kthread.c:341) 


Finger prints:
dump_stack_lvl:check_noncircular:check_prev_add:validate_chain