======================================
| [  838.776638][T14940]  #1: ffffffffa7d8c900 (rcu_read_lock_bh){....}-{1:3}, at: fib6_nh_age_exceptions.part.0 (./include/linux/bottom_half.h:20 (discriminator 1) ./include/linux/rcupdate.h:903 (discriminator 1) net/ipv6/route.c:2190 (discriminator 1))
| [  838.776909][T14940]  #2: ffffffffa85afbd8 (rt6_exception_lock){+.-.}-{3:3}, at: fib6_nh_age_exceptions.part.0 (net/ipv6/route.c:2192)
| [  838.777172][T14940]
| [  838.777172][T14940] stack backtrace:
[  838.777340][T14940] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  838.777341][T14940] Call Trace:
[  838.777343][T14940]  <TASK>
[  838.777344][T14940]  dump_stack_lvl (lib/dump_stack.c:122)
[  838.777350][T14940]  lockdep_rcu_suspicious.cold (kernel/locking/lockdep.c:6877)
[  838.777356][T14940]  ___neigh_lookup_noref.constprop.0 (./include/net/neighbour.h:312 (discriminator 13))
[  838.777361][T14940]  rt6_age_examine_exception (net/ipv6/route.c:2167)
[  838.777365][T14940]  ? __ip6_del_rt (net/ipv6/route.c:2140)
[  838.777368][T14940]  ? fib6_nh_get_excptn_bucket (net/ipv6/route.c:1671 (discriminator 4))
[  838.777371][T14940]  fib6_nh_age_exceptions.part.0 (net/ipv6/route.c:2195 (discriminator 10))
[  838.777375][T14940]  rt6_age_exceptions (net/ipv6/route.c:2235)
[  838.777377][T14940]  ? rt6_flush_exceptions (net/ipv6/route.c:2223)
[  838.777379][T14940]  ? rcu_is_watching (./include/linux/context_tracking.h:128 (discriminator 1) kernel/rcu/tree.c:752 (discriminator 1))
[  838.777383][T14940]  ? rcu_is_watching (./include/linux/context_tracking.h:128 (discriminator 1) kernel/rcu/tree.c:752 (discriminator 1))
[  838.777385][T14940]  fib6_age_exceptions (net/ipv6/ip6_fib.c:2362 (discriminator 1))
[  838.777388][T14940]  fib6_add_rt2node (./include/net/ip6_fib.h:561 net/ipv6/ip6_fib.c:1139)
[  838.777390][T14940]  ? pcpu_alloc_noprof (mm/percpu.c:1906)
[  838.777398][T14940]  ? fib6_age_exceptions (net/ipv6/ip6_fib.c:1086)
[  838.777401][T14940]  ? fib6_add_1.constprop.0 (net/ipv6/ip6_fib.c:776 (discriminator 4))
[  838.777407][T14940]  ? fib6_add (net/ipv6/ip6_fib.c:1536)
[  838.777408][T14940]  fib6_add (net/ipv6/ip6_fib.c:1536)
[  838.777411][T14940]  ? lock_acquire.part.0 (kernel/locking/lockdep.c:470 kernel/locking/lockdep.c:5870)
[  838.777414][T14940]  ? fib6_add_rt2node (net/ipv6/ip6_fib.c:1428)
[  838.777419][T14940]  ip6_route_add (./include/linux/spinlock.h:395 net/ipv6/route.c:1353 net/ipv6/route.c:3955)
[  838.777421][T14940]  ? ip6_route_multipath_add (net/ipv6/route.c:5644)
[  838.777424][T14940]  inet6_rtm_newroute (net/ipv6/route.c:5658)
[  838.777426][T14940]  ? ip6_route_multipath_add (net/ipv6/route.c:5644)
[  838.777427][T14940]  ? lock_acquire.part.0 (kernel/locking/lockdep.c:470 kernel/locking/lockdep.c:5870)
[  838.777429][T14940]  ? find_held_lock (kernel/locking/lockdep.c:5350 (discriminator 1))
[  838.777437][T14940]  ? __lock_release.isra.0 (kernel/locking/lockdep.c:5536)
[  838.777439][T14940]  ? rtnetlink_rcv_msg (./include/linux/rcupdate.h:322 (discriminator 1) ./include/linux/rcupdate.h:881 (discriminator 1) net/core/rtnetlink.c:6978 (discriminator 1))
[  838.777444][T14940]  ? ip6_route_multipath_add (net/ipv6/route.c:5644)
[  838.777445][T14940]  rtnetlink_rcv_msg (net/core/rtnetlink.c:6980)
[  838.777449][T14940]  ? rtnl_fdb_dump (net/core/rtnetlink.c:6883)
[  838.777451][T14940]  ? __lock_acquire (kernel/locking/lockdep.c:5237 (discriminator 1))
[  838.777454][T14940]  ? lock_acquire.part.0 (kernel/locking/lockdep.c:470 kernel/locking/lockdep.c:5870)
[  838.777456][T14940]  ? find_held_lock (kernel/locking/lockdep.c:5350 (discriminator 1))
[  838.777459][T14940]  netlink_rcv_skb (net/netlink/af_netlink.c:2550)
[  838.777462][T14940]  ? rtnl_fdb_dump (net/core/rtnetlink.c:6883)
[  838.777465][T14940]  ? netlink_ack (net/netlink/af_netlink.c:2527)
[  838.777471][T14940]  ? netlink_deliver_tap (./include/linux/rcupdate.h:322 (discriminator 1) ./include/linux/rcupdate.h:881 (discriminator 1) ./include/net/netns/generic.h:48 (discriminator 1) net/netlink/af_netlink.c:333 (discriminator 1))
[  838.777472][T14940]  ? netlink_deliver_tap (./include/linux/rcupdate.h:322 (discriminator 1) ./include/linux/rcupdate.h:881 (discriminator 1) net/netlink/af_netlink.c:340 (discriminator 1))
[  838.777478][T14940]  netlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344)
[  838.777482][T14940]  ? netlink_attachskb (net/netlink/af_netlink.c:1329)
[  838.777483][T14940]  ? __alloc_skb (./include/linux/bottom_half.h:20 (discriminator 1) net/core/skbuff.c:695 (discriminator 1))
[  838.777486][T14940]  ? napi_skb_cache_get (net/core/skbuff.c:674)
[  838.777488][T14940]  ? lock_acquire.part.0 (kernel/locking/lockdep.c:470 kernel/locking/lockdep.c:5870)
[  838.777490][T14940]  ? __lock_acquire (kernel/locking/lockdep.c:5237 (discriminator 1))
[  838.777493][T14940]  netlink_sendmsg (net/netlink/af_netlink.c:1894)
[  838.777497][T14940]  ? netlink_unicast (net/netlink/af_netlink.c:1813)
[  838.777500][T14940]  ? __might_fault (mm/memory.c:7218 (discriminator 4))
[  838.777505][T14940]  ____sys_sendmsg (net/socket.c:721 (discriminator 4) net/socket.c:736 (discriminator 4) net/socket.c:2585 (discriminator 4))
[  838.777507][T14940]  ? copy_msghdr_from_user (net/socket.c:2525)
[  838.777509][T14940]  ? get_timestamp.constprop.0 (net/socket.c:2531)
[  838.777511][T14940]  ? move_addr_to_kernel (net/socket.c:2511)
[  838.777514][T14940]  ? stack_depot_save_flags (lib/stackdepot.c:609 (discriminator 4) lib/stackdepot.c:676 (discriminator 4))
[  838.777518][T14940]  ? rcu_read_lock_any_held (kernel/rcu/update.c:386 (discriminator 1) kernel/rcu/update.c:380 (discriminator 1))
[  838.777524][T14940]  ___sys_sendmsg (net/socket.c:2641)
[  838.777525][T14940]  ? __call_rcu_common.constprop.0 (./arch/x86/include/asm/irqflags.h:26 ./arch/x86/include/asm/irqflags.h:109 ./arch/x86/include/asm/irqflags.h:127 kernel/rcu/tree.c:3133)
[  838.777529][T14940]  ? copy_msghdr_from_user (net/socket.c:2628)
[  838.777543][T14940]  __sys_sendmsg (net/socket.c:2671 (discriminator 1))
[  838.777545][T14940]  ? __sys_sendmsg_sock (net/socket.c:2656)
[  838.777547][T14940]  ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4473)
[  838.777551][T14940]  ? __call_rcu_common.constprop.0 (./arch/x86/include/asm/irqflags.h:26 ./arch/x86/include/asm/irqflags.h:109 ./arch/x86/include/asm/irqflags.h:151 kernel/rcu/tree.c:3156)
[  838.777557][T14940]  ? do_raw_spin_unlock (./arch/x86/include/asm/atomic.h:23 ./include/linux/atomic/atomic-arch-fallback.h:457 ./include/linux/atomic/atomic-instrumented.h:33 ./include/asm-generic/qspinlock.h:57 kernel/locking/spinlock_debug.c:101 kernel/locking/spinlock_debug.c:141)
[  838.777559][T14940]  ? rcu_is_watching (./include/linux/context_tracking.h:128 (discriminator 1) kernel/rcu/tree.c:752 (discriminator 1))
[  838.777562][T14940]  do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1))
[  838.777564][T14940]  ? exc_page_fault (arch/x86/mm/fault.c:1480 (discriminator 3) arch/x86/mm/fault.c:1527 (discriminator 3))
[  838.777567][T14940]  entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[  838.777569][T14940] RIP: 0033:0x7f2fbc84ac5e
[  838.777572][T14940] Code: 4d 89 d8 e8 34 bd 00 00 4c 8b 5d f8 41 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 11 c9 c3 0f 1f 80 00 00 00 00 48 8b 45 10 0f 05 <c9> c3 83 e2 39 83 fa 08 75 e7 e8 13 ff ff ff 0f 1f 00 f3 0f 1e fa
All code
========
   0:	4d 89 d8             	mov    %r11,%r8
   3:	e8 34 bd 00 00       	call   0xbd3c
   8:	4c 8b 5d f8          	mov    -0x8(%rbp),%r11
   c:	41 8b 93 08 03 00 00 	mov    0x308(%r11),%edx
  13:	59                   	pop    %rcx
  14:	5e                   	pop    %rsi
  15:	48 83 f8 fc          	cmp    $0xfffffffffffffffc,%rax
  19:	74 11                	je     0x2c
  1b:	c9                   	leave
  1c:	c3                   	ret
  1d:	0f 1f 80 00 00 00 00 	nopl   0x0(%rax)
  24:	48 8b 45 10          	mov    0x10(%rbp),%rax
  28:	0f 05                	syscall
  2a:*	c9                   	leave		<-- trapping instruction
  2b:	c3                   	ret
  2c:	83 e2 39             	and    $0x39,%edx
  2f:	83 fa 08             	cmp    $0x8,%edx
  32:	75 e7                	jne    0x1b
  34:	e8 13 ff ff ff       	call   0xffffffffffffff4c
  39:	0f 1f 00             	nopl   (%rax)
  3c:	f3 0f 1e fa          	endbr64

Code starting with the faulting instruction
===========================================
   0:	c9                   	leave
   1:	c3                   	ret
   2:	83 e2 39             	and    $0x39,%edx
   5:	83 fa 08             	cmp    $0x8,%edx
   8:	75 e7                	jne    0xfffffffffffffff1
   a:	e8 13 ff ff ff       	call   0xffffffffffffff22
   f:	0f 1f 00             	nopl   (%rax)
  12:	f3 0f 1e fa          	endbr64
[  838.777574][T14940] RSP: 002b:00007fffc9bbd510 EFLAGS: 00000202 ORIG_RAX: 000000000000002e
[  838.777577][T14940] RAX: ffffffffffffffda RBX: 00007fffc9bbfb20 RCX: 00007f2fbc84ac5e
[  838.777578][T14940] RDX: 0000000000000000 RSI: 00007fffc9bbd5d0 RDI: 0000000000000005
[  838.777579][T14940] RBP: 00007fffc9bbd520 R08: 0000000000000000 R09: 0000000000000000
[  838.777579][T14940] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000


Finger prints:
rt6_age_examine_exception:rt6_age_exceptions:fib6_age_exceptions:fib6_add_rt2node:fib6_add