IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready
IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready

===============================
[ INFO: suspicious RCU usage. ]
4.4.141-g9664bde #11 Not tainted
-------------------------------
kernel/rcu/tree_plugin.h:685 Illegal synchronize_rcu() in RCU read-side critical section!

other info that might help us debug this:


rcu_scheduler_active = 1, debug_locks = 0
2 locks held by syz-executor0/4202:
 #0:  (rcu_read_lock_bh){......}, at: [<ffffffff83429965>] ip6_finish_output2+0x1d5/0x1ca0 net/ipv6/ip6_output.c:71
 #1:  (&n->lock){++--..}, at: [<ffffffff82fa2c4f>] __neigh_event_send+0x2f/0xc50 net/core/neighbour.c:969

stack backtrace:
CPU: 1 PID: 4202 Comm: syz-executor0 Not tainted 4.4.141-g9664bde #11
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 b30595947bd15cf7 ffff8801d6ac7000 ffffffff81e0e18d
 ffff8800b91de000 0000000000000000 0000000000000001 ffffffff83a676c0
 ffff8801d83c1558 ffff8801d6ac7030 ffffffff8140e407 ffff8801d83c1400
Call Trace:
 [<ffffffff81e0e18d>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81e0e18d>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff8140e407>] lockdep_rcu_suspicious.cold.47+0x110/0x141 kernel/locking/lockdep.c:4305
 [<ffffffff81281aa8>] synchronize_rcu+0x78/0xa0 kernel/rcu/tree_plugin.h:682
 [<ffffffff8359f63a>] __l2tp_session_unhash+0x38a/0x520 net/l2tp/l2tp_core.c:1702
 [<ffffffff8359f99b>] l2tp_tunnel_closeall+0x1cb/0x350 net/l2tp/l2tp_core.c:1270
 [<ffffffff835a0272>] l2tp_tunnel_destruct+0x2f2/0x590 net/l2tp/l2tp_core.c:1230
 [<ffffffff82f2f3ec>] sk_destruct+0x4c/0x4c0 net/core/sock.c:1447
 [<ffffffff82f2f8af>] __sk_free+0x4f/0x220 net/core/sock.c:1480
 [<ffffffff82f31833>] sock_wfree+0x103/0x140 net/core/sock.c:1667
 [<ffffffff82f354b3>] skb_release_head_state+0x103/0x210 net/core/skbuff.c:646
 [<ffffffff82f37395>] skb_release_all+0x15/0x60 net/core/skbuff.c:659
 [<ffffffff82f373f5>] __kfree_skb+0x15/0x20 net/core/skbuff.c:675
 [<ffffffff82f374f7>] kfree_skb+0xf7/0x3e0 net/core/skbuff.c:696
 [<ffffffff82fa3272>] __neigh_event_send+0x652/0xc50 net/core/neighbour.c:1016
 [<ffffffff82fa8b8b>] neigh_event_send include/net/neighbour.h:431 [inline]
 [<ffffffff82fa8b8b>] neigh_resolve_output+0x4eb/0x790 net/core/neighbour.c:1310
 [<ffffffff8342a0b9>] dst_neigh_output include/net/dst.h:461 [inline]
 [<ffffffff8342a0b9>] ip6_finish_output2+0x929/0x1ca0 net/ipv6/ip6_output.c:113
 [<ffffffff834336f8>] ip6_finish_output+0x3b8/0x760 net/ipv6/ip6_output.c:131
 [<ffffffff83433c58>] NF_HOOK_COND include/linux/netfilter.h:240 [inline]
 [<ffffffff83433c58>] ip6_output+0x1b8/0x520 net/ipv6/ip6_output.c:145
 [<ffffffff8355d08b>] dst_output include/net/dst.h:498 [inline]
 [<ffffffff8355d08b>] ip6_local_out+0x9b/0x180 net/ipv6/output_core.c:169
 [<ffffffff83435c91>] ip6_send_skb+0xa1/0x340 net/ipv6/ip6_output.c:1725
 [<ffffffff83491b3a>] udp_v6_send_skb+0x5ba/0xe70 net/ipv6/udp.c:1066
 [<ffffffff834974de>] udpv6_sendmsg+0x1f2e/0x24c0 net/ipv6/udp.c:1330
 [<ffffffff83301213>] inet_sendmsg+0x203/0x4d0 net/ipv4/af_inet.c:755
 [<ffffffff82f1e2fc>] sock_sendmsg_nosec net/socket.c:625 [inline]
 [<ffffffff82f1e2fc>] sock_sendmsg+0xcc/0x110 net/socket.c:635
 [<ffffffff82f1fac1>] ___sys_sendmsg+0x441/0x880 net/socket.c:1962
 [<ffffffff82f22144>] __sys_sendmmsg+0x1d4/0x2e0 net/socket.c:2040
 [<ffffffff8300bc02>] C_SYSC_sendmmsg net/compat.c:728 [inline]
 [<ffffffff8300bc02>] compat_SyS_sendmmsg+0x32/0x40 net/compat.c:725
 [<ffffffff81006d96>] do_syscall_32_irqs_on arch/x86/entry/common.c:393 [inline]
 [<ffffffff81006d96>] do_fast_syscall_32+0x326/0x8b0 arch/x86/entry/common.c:460
 [<ffffffff838c466a>] sysenter_flags_fixed+0xd/0x17
BUG: sleeping function called from invalid context at kernel/sched/completion.c:90
in_atomic(): 1, irqs_disabled(): 0, pid: 4202, name: syz-executor0
INFO: lockdep is turned off.
Preemption disabled at:[<ffffffff834336f8>] ip6_finish_output+0x3b8/0x760 net/ipv6/ip6_output.c:131

CPU: 1 PID: 4202 Comm: syz-executor0 Not tainted 4.4.141-g9664bde #11
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 b30595947bd15cf7 ffff8801d6ac6d80 ffffffff81e0e18d
 ffff8800b91de000 0000000000000000 ffff8800b91de000 000000000000005a
 ffff8800b91de000 ffff8801d6ac6db8 ffffffff8140c525 ffff8800b91de000
Call Trace:
 [<ffffffff81e0e18d>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81e0e18d>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff8140c525>] ___might_sleep.cold.116+0x1bd/0x1d3 kernel/sched/core.c:7988
 [<ffffffff811a47a0>] __might_sleep+0x90/0x1a0 kernel/sched/core.c:7948
 [<ffffffff838b7ca9>] __wait_for_common kernel/sched/completion.c:90 [inline]
 [<ffffffff838b7ca9>] wait_for_common kernel/sched/completion.c:101 [inline]
 [<ffffffff838b7ca9>] wait_for_completion+0x89/0x2e0 kernel/sched/completion.c:122
 [<ffffffff812773a7>] __wait_rcu_gp+0x137/0x1b0 kernel/rcu/update.c:347
 [<ffffffff8127faa4>] synchronize_rcu.part.55+0x94/0xd0 kernel/rcu/tree_plugin.h:691
 [<ffffffff81281a67>] synchronize_rcu+0x37/0xa0 kernel/rcu/tree_plugin.h:692
 [<ffffffff8359f63a>] __l2tp_session_unhash+0x38a/0x520 net/l2tp/l2tp_core.c:1702
 [<ffffffff8359f99b>] l2tp_tunnel_closeall+0x1cb/0x350 net/l2tp/l2tp_core.c:1270
 [<ffffffff835a0272>] l2tp_tunnel_destruct+0x2f2/0x590 net/l2tp/l2tp_core.c:1230
 [<ffffffff82f2f3ec>] sk_destruct+0x4c/0x4c0 net/core/sock.c:1447
 [<ffffffff82f2f8af>] __sk_free+0x4f/0x220 net/core/sock.c:1480
 [<ffffffff82f31833>] sock_wfree+0x103/0x140 net/core/sock.c:1667
 [<ffffffff82f354b3>] skb_release_head_state+0x103/0x210 net/core/skbuff.c:646
 [<ffffffff82f37395>] skb_release_all+0x15/0x60 net/core/skbuff.c:659
 [<ffffffff82f373f5>] __kfree_skb+0x15/0x20 net/core/skbuff.c:675
 [<ffffffff82f374f7>] kfree_skb+0xf7/0x3e0 net/core/skbuff.c:696
 [<ffffffff82fa3272>] __neigh_event_send+0x652/0xc50 net/core/neighbour.c:1016
 [<ffffffff82fa8b8b>] neigh_event_send include/net/neighbour.h:431 [inline]
 [<ffffffff82fa8b8b>] neigh_resolve_output+0x4eb/0x790 net/core/neighbour.c:1310
 [<ffffffff8342a0b9>] dst_neigh_output include/net/dst.h:461 [inline]
 [<ffffffff8342a0b9>] ip6_finish_output2+0x929/0x1ca0 net/ipv6/ip6_output.c:113
 [<ffffffff834336f8>] ip6_finish_output+0x3b8/0x760 net/ipv6/ip6_output.c:131
 [<ffffffff83433c58>] NF_HOOK_COND include/linux/netfilter.h:240 [inline]
 [<ffffffff83433c58>] ip6_output+0x1b8/0x520 net/ipv6/ip6_output.c:145
 [<ffffffff8355d08b>] dst_output include/net/dst.h:498 [inline]
 [<ffffffff8355d08b>] ip6_local_out+0x9b/0x180 net/ipv6/output_core.c:169
 [<ffffffff83435c91>] ip6_send_skb+0xa1/0x340 net/ipv6/ip6_output.c:1725
 [<ffffffff83491b3a>] udp_v6_send_skb+0x5ba/0xe70 net/ipv6/udp.c:1066
 [<ffffffff834974de>] udpv6_sendmsg+0x1f2e/0x24c0 net/ipv6/udp.c:1330
 [<ffffffff83301213>] inet_sendmsg+0x203/0x4d0 net/ipv4/af_inet.c:755
 [<ffffffff82f1e2fc>] sock_sendmsg_nosec net/socket.c:625 [inline]
 [<ffffffff82f1e2fc>] sock_sendmsg+0xcc/0x110 net/socket.c:635
 [<ffffffff82f1fac1>] ___sys_sendmsg+0x441/0x880 net/socket.c:1962
 [<ffffffff82f22144>] __sys_sendmmsg+0x1d4/0x2e0 net/socket.c:2040
 [<ffffffff8300bc02>] C_SYSC_sendmmsg net/compat.c:728 [inline]
 [<ffffffff8300bc02>] compat_SyS_sendmmsg+0x32/0x40 net/compat.c:725
 [<ffffffff81006d96>] do_syscall_32_irqs_on arch/x86/entry/common.c:393 [inline]
 [<ffffffff81006d96>] do_fast_syscall_32+0x326/0x8b0 arch/x86/entry/common.c:460
 [<ffffffff838c466a>] sysenter_flags_fixed+0xd/0x17
BUG: scheduling while atomic: syz-executor0/4202/0x00000402
INFO: lockdep is turned off.
Modules linked in:
Preemption disabled at:[<ffffffff834336f8>] ip6_finish_output+0x3b8/0x760 net/ipv6/ip6_output.c:131

CPU: 1 PID: 4202 Comm: syz-executor0 Not tainted 4.4.141-g9664bde #11
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 b30595947bd15cf7 ffff8801d6ac6bd8 ffffffff81e0e18d
 ffff8800b91de000 0000000000000402 000000000001f4c0 0000000000000000
 0000000000000001 ffff8801d6ac6bf8 ffffffff8140c619 ffff8801db31f4c0
Call Trace:
 [<ffffffff81e0e18d>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81e0e18d>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff8140c619>] __schedule_bug.cold.117+0xde/0x100 kernel/sched/core.c:3138
 [<ffffffff838b3f6f>] schedule_debug kernel/sched/core.c:3153 [inline]
 [<ffffffff838b3f6f>] __schedule+0x11ff/0x1d70 kernel/sched/core.c:3265
 [<ffffffff838b4cda>] schedule+0x7a/0x1b0 kernel/sched/core.c:3355
 [<ffffffff838c00f1>] schedule_timeout+0x481/0x8b0 kernel/time/timer.c:1515
 [<ffffffff838b7e1e>] do_wait_for_common kernel/sched/completion.c:75 [inline]
 [<ffffffff838b7e1e>] __wait_for_common kernel/sched/completion.c:93 [inline]
 [<ffffffff838b7e1e>] wait_for_common kernel/sched/completion.c:101 [inline]
 [<ffffffff838b7e1e>] wait_for_completion+0x1fe/0x2e0 kernel/sched/completion.c:122
 [<ffffffff812773a7>] __wait_rcu_gp+0x137/0x1b0 kernel/rcu/update.c:347
 [<ffffffff8127faa4>] synchronize_rcu.part.55+0x94/0xd0 kernel/rcu/tree_plugin.h:691
 [<ffffffff81281a67>] synchronize_rcu+0x37/0xa0 kernel/rcu/tree_plugin.h:692
 [<ffffffff8359f63a>] __l2tp_session_unhash+0x38a/0x520 net/l2tp/l2tp_core.c:1702
 [<ffffffff8359f99b>] l2tp_tunnel_closeall+0x1cb/0x350 net/l2tp/l2tp_core.c:1270
 [<ffffffff835a0272>] l2tp_tunnel_destruct+0x2f2/0x590 net/l2tp/l2tp_core.c:1230
 [<ffffffff82f2f3ec>] sk_destruct+0x4c/0x4c0 net/core/sock.c:1447
 [<ffffffff82f2f8af>] __sk_free+0x4f/0x220 net/core/sock.c:1480
 [<ffffffff82f31833>] sock_wfree+0x103/0x140 net/core/sock.c:1667
 [<ffffffff82f354b3>] skb_release_head_state+0x103/0x210 net/core/skbuff.c:646
 [<ffffffff82f37395>] skb_release_all+0x15/0x60 net/core/skbuff.c:659
 [<ffffffff82f373f5>] __kfree_skb+0x15/0x20 net/core/skbuff.c:675
 [<ffffffff82f374f7>] kfree_skb+0xf7/0x3e0 net/core/skbuff.c:696
 [<ffffffff82fa3272>] __neigh_event_send+0x652/0xc50 net/core/neighbour.c:1016
 [<ffffffff82fa8b8b>] neigh_event_send include/net/neighbour.h:431 [inline]
 [<ffffffff82fa8b8b>] neigh_resolve_output+0x4eb/0x790 net/core/neighbour.c:1310
 [<ffffffff8342a0b9>] dst_neigh_output include/net/dst.h:461 [inline]
 [<ffffffff8342a0b9>] ip6_finish_output2+0x929/0x1ca0 net/ipv6/ip6_output.c:113
 [<ffffffff834336f8>] ip6_finish_output+0x3b8/0x760 net/ipv6/ip6_output.c:131
 [<ffffffff83433c58>] NF_HOOK_COND include/linux/netfilter.h:240 [inline]
 [<ffffffff83433c58>] ip6_output+0x1b8/0x520 net/ipv6/ip6_output.c:145
 [<ffffffff8355d08b>] dst_output include/net/dst.h:498 [inline]
 [<ffffffff8355d08b>] ip6_local_out+0x9b/0x180 net/ipv6/output_core.c:169
 [<ffffffff83435c91>] ip6_send_skb+0xa1/0x340 net/ipv6/ip6_output.c:1725
 [<ffffffff83491b3a>] udp_v6_send_skb+0x5ba/0xe70 net/ipv6/udp.c:1066
 [<ffffffff834974de>] udpv6_sendmsg+0x1f2e/0x24c0 net/ipv6/udp.c:1330
 [<ffffffff83301213>] inet_sendmsg+0x203/0x4d0 net/ipv4/af_inet.c:755
 [<ffffffff82f1e2fc>] sock_sendmsg_nosec net/socket.c:625 [inline]
 [<ffffffff82f1e2fc>] sock_sendmsg+0xcc/0x110 net/socket.c:635
 [<ffffffff82f1fac1>] ___sys_sendmsg+0x441/0x880 net/socket.c:1962
 [<ffffffff82f22144>] __sys_sendmmsg+0x1d4/0x2e0 net/socket.c:2040
 [<ffffffff8300bc02>] C_SYSC_sendmmsg net/compat.c:728 [inline]
 [<ffffffff8300bc02>] compat_SyS_sendmmsg+0x32/0x40 net/compat.c:725
 [<ffffffff81006d96>] do_syscall_32_irqs_on arch/x86/entry/common.c:393 [inline]
 [<ffffffff81006d96>] do_fast_syscall_32+0x326/0x8b0 arch/x86/entry/common.c:460
 [<ffffffff838c466a>] sysenter_flags_fixed+0xd/0x17
NOHZ: local_softirq_pending 282