pktgen: kernel_thread() failed for cpu 1
pktgen: Cannot create thread for cpu 1 (-4)
pktgen: Initialization failed for all threads

===============================
[ INFO: suspicious RCU usage. ]
4.9.111-g03c70fe #58 Not tainted
-------------------------------
net/ipv6/ip6_fib.c:1471 suspicious rcu_dereference_protected() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 0
6 locks held by kworker/u4:6/12044:
 #0:  ("%s""netns"){.+.+.+}, at: [<ffffffff8118d03e>] work_static include/linux/workqueue.h:186 [inline]
 #0:  ("%s""netns"){.+.+.+}, at: [<ffffffff8118d03e>] set_work_data kernel/workqueue.c:617 [inline]
 #0:  ("%s""netns"){.+.+.+}, at: [<ffffffff8118d03e>] set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0:  ("%s""netns"){.+.+.+}, at: [<ffffffff8118d03e>] process_one_work+0x6ee/0x1500 kernel/workqueue.c:2085
 #1:  (net_cleanup_work){+.+.+.}, at: [<ffffffff8118d078>] process_one_work+0x728/0x1500 kernel/workqueue.c:2089
 #2:  (net_mutex){+.+.+.}, at: [<ffffffff8305ba3f>] cleanup_net+0x13f/0x630 net/core/net_namespace.c:439
 #3:  (rtnl_mutex){+.+.+.}, at: [<ffffffff830b4937>] rtnl_lock+0x17/0x20 net/core/rtnetlink.c:70
 #4:  (rcu_read_lock){......}, at: [<ffffffff835a6b50>] __fib6_clean_all+0x0/0x220 net/ipv6/ip6_fib.c:1703
 #5:  (&tb->tb6_lock){++--..}, at: [<ffffffff835a6c30>] __fib6_clean_all+0xe0/0x220 net/ipv6/ip6_fib.c:1717

stack backtrace:
CPU: 0 PID: 12044 Comm: kworker/u4:6 Not tainted 4.9.111-g03c70fe #58
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
 ffff8801c498f0b8 ffffffff81eb2729 ffff88019c9c9800 0000000000000000
 0000000000000002 ffffffff84166340 ffffed0038931e66 ffff8801c498f0e8
 ffffffff81426090 ffff8801c59ec380 ffff8801c498f2e0 ffff8801c59ec380
Call Trace:
 [<ffffffff81eb2729>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb2729>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81426090>] lockdep_rcu_suspicious.cold.48+0x110/0x141 kernel/locking/lockdep.c:4455
 [<ffffffff835ad0e3>] fib6_del+0x773/0xa20 net/ipv6/ip6_fib.c:1470
 [<ffffffff835ad5b0>] fib6_clean_node+0x220/0x4c0 net/ipv6/ip6_fib.c:1657
 [<ffffffff835a4895>] fib6_walk_continue+0x3e5/0x640 net/ipv6/ip6_fib.c:1583
 [<ffffffff835a69c9>] fib6_walk+0xd9/0x150 net/ipv6/ip6_fib.c:1628
 [<ffffffff835a6b13>] fib6_clean_tree+0xd3/0x110 net/ipv6/ip6_fib.c:1702
 [<ffffffff835a6c49>] __fib6_clean_all+0xf9/0x220 net/ipv6/ip6_fib.c:1718
 [<ffffffff835ad877>] fib6_clean_all+0x27/0x30 net/ipv6/ip6_fib.c:1729
 [<ffffffff835a3291>] rt6_ifdown+0xa1/0x7f0 net/ipv6/route.c:2716
 [<ffffffff8357ded0>] addrconf_ifdown+0xd0/0x10e0 net/ipv6/addrconf.c:3569
 [<ffffffff835859d8>] addrconf_notify+0x7f8/0x2160 net/ipv6/addrconf.c:3493
 [<ffffffff811a1874>] notifier_call_chain+0xb4/0x1d0 kernel/notifier.c:93
 [<ffffffff811a19fd>] __raw_notifier_call_chain kernel/notifier.c:394 [inline]
 [<ffffffff811a19fd>] raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401
 [<ffffffff83067f85>] call_netdevice_notifiers_info+0x55/0x70 net/core/dev.c:1647
 [<ffffffff83068bb2>] call_netdevice_notifiers net/core/dev.c:1663 [inline]
 [<ffffffff83068bb2>] dev_close_many+0x252/0x380 net/core/dev.c:1456
 [<ffffffff8306dd58>] rollback_registered_many+0x268/0x920 net/core/dev.c:6810
 [<ffffffff830716ab>] unregister_netdevice_many.part.106+0x1b/0x110 net/core/dev.c:7879
 [<ffffffff83071b43>] unregister_netdevice_many net/core/dev.c:7878 [inline]
 [<ffffffff83071b43>] default_device_exit_batch+0x353/0x410 net/core/dev.c:8337
 [<ffffffff83058da5>] ops_exit_list.isra.6+0x105/0x160 net/core/net_namespace.c:139
 [<ffffffff8305bc21>] cleanup_net+0x321/0x630 net/core/net_namespace.c:473
 [<ffffffff8118d131>] process_one_work+0x7e1/0x1500 kernel/workqueue.c:2092
 [<ffffffff8118df26>] worker_thread+0xd6/0x10a0 kernel/workqueue.c:2226
 [<ffffffff8119d05d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839f8e9c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
9pnet: Insufficient options for proto=fd
9pnet: Insufficient options for proto=fd