======================================
| [ 1584.747245][ T8986] 1 lock held by ip/8986:
| [ 1584.747389][ T8986]  #0: ffffffff998a2728 (rtnl_mutex){+.+.}-{4:4}, at: rtm_new_nexthop (net/ipv4/nexthop.c:3222 net/ipv4/nexthop.c:3277)
| [ 1584.747680][ T8986]
| [ 1584.747680][ T8986] stack backtrace:
[ 1584.747892][ T8986] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 1584.747894][ T8986] Call Trace:
[ 1584.747896][ T8986]  <TASK>
[ 1584.747898][ T8986]  dump_stack_lvl (lib/dump_stack.c:122)
[ 1584.747905][ T8986]  lockdep_rcu_suspicious.cold (kernel/locking/lockdep.c:6877)
[ 1584.747910][ T8986]  fib6_update_sernum (net/ipv6/ip6_fib.c:111 (discriminator 10))
[ 1584.747915][ T8986]  nh_rt_cache_flush (net/ipv4/nexthop.c:2211 (discriminator 4))
[ 1584.747919][ T8986]  replace_nexthop (net/ipv4/nexthop.c:2577)
[ 1584.747923][ T8986]  insert_nexthop (net/ipv4/nexthop.c:2612)
[ 1584.747926][ T8986]  ? nexthop_create (net/ipv4/nexthop.c:2930)
[ 1584.747929][ T8986]  rtm_new_nexthop (net/ipv4/nexthop.c:2977 net/ipv4/nexthop.c:3281)
[ 1584.747933][ T8986]  ? insert_nexthop (net/ipv4/nexthop.c:3252)
[ 1584.747934][ T8986]  ? lock_acquire.part.0 (kernel/locking/lockdep.c:470 kernel/locking/lockdep.c:5870)
[ 1584.747937][ T8986]  ? find_held_lock (kernel/locking/lockdep.c:5350 (discriminator 1))
[ 1584.747944][ T8986]  ? lock_acquire.part.0 (kernel/locking/lockdep.c:470 kernel/locking/lockdep.c:5870)
[ 1584.747945][ T8986]  ? find_held_lock (kernel/locking/lockdep.c:5350 (discriminator 1))
[ 1584.747951][ T8986]  ? find_held_lock (kernel/locking/lockdep.c:5350 (discriminator 1))
[ 1584.747953][ T8986]  ? insert_nexthop (net/ipv4/nexthop.c:3252)
[ 1584.747955][ T8986]  ? __lock_release.isra.0 (kernel/locking/lockdep.c:5536)
[ 1584.747958][ T8986]  ? insert_nexthop (net/ipv4/nexthop.c:3252)
[ 1584.747960][ T8986]  rtnetlink_rcv_msg (net/core/rtnetlink.c:6958)
[ 1584.747965][ T8986]  ? rtnl_fdb_dump (net/core/rtnetlink.c:6861)
[ 1584.747967][ T8986]  ? __lock_acquire (kernel/locking/lockdep.c:5237 (discriminator 1))
[ 1584.747971][ T8986]  ? lock_acquire.part.0 (kernel/locking/lockdep.c:470 kernel/locking/lockdep.c:5870)
[ 1584.747972][ T8986]  ? find_held_lock (kernel/locking/lockdep.c:5350 (discriminator 1))
[ 1584.747976][ T8986]  netlink_rcv_skb (net/netlink/af_netlink.c:2550)
[ 1584.747978][ T8986]  ? rtnl_fdb_dump (net/core/rtnetlink.c:6861)
[ 1584.747982][ T8986]  ? netlink_ack (net/netlink/af_netlink.c:2527)
[ 1584.747987][ T8986]  ? 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))
[ 1584.747988][ T8986]  ? 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))
[ 1584.747992][ T8986]  netlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344)
[ 1584.747995][ T8986]  ? netlink_attachskb (net/netlink/af_netlink.c:1329)
[ 1584.747996][ T8986]  ? __alloc_skb (./include/linux/bottom_half.h:20 (discriminator 1) net/core/skbuff.c:695 (discriminator 1))
[ 1584.747999][ T8986]  ? napi_skb_cache_get (net/core/skbuff.c:674)
[ 1584.748001][ T8986]  ? lock_acquire.part.0 (kernel/locking/lockdep.c:470 kernel/locking/lockdep.c:5870)
[ 1584.748003][ T8986]  ? __lock_acquire (kernel/locking/lockdep.c:5237 (discriminator 1))
[ 1584.748006][ T8986]  netlink_sendmsg (net/netlink/af_netlink.c:1894)
[ 1584.748009][ T8986]  ? netlink_unicast (net/netlink/af_netlink.c:1813)
[ 1584.748013][ T8986]  ? __might_fault (mm/memory.c:7218 (discriminator 4))
[ 1584.748018][ T8986]  ____sys_sendmsg (net/socket.c:721 (discriminator 4) net/socket.c:736 (discriminator 4) net/socket.c:2585 (discriminator 4))
[ 1584.748021][ T8986]  ? copy_msghdr_from_user (net/socket.c:2525)
[ 1584.748022][ T8986]  ? get_timestamp.constprop.0 (net/socket.c:2531)
[ 1584.748024][ T8986]  ? move_addr_to_kernel (net/socket.c:2511)
[ 1584.748027][ T8986]  ? stack_depot_save_flags (lib/stackdepot.c:609 (discriminator 4) lib/stackdepot.c:676 (discriminator 4))
[ 1584.748031][ T8986]  ? rcu_read_lock_any_held (kernel/rcu/update.c:386 (discriminator 1) kernel/rcu/update.c:380 (discriminator 1))
[ 1584.748036][ T8986]  ___sys_sendmsg (net/socket.c:2641)
[ 1584.748038][ T8986]  ? __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)
[ 1584.748041][ T8986]  ? copy_msghdr_from_user (net/socket.c:2628)
[ 1584.748058][ T8986]  __sys_sendmsg (net/socket.c:2671 (discriminator 1))
[ 1584.748061][ T8986]  ? __sys_sendmsg_sock (net/socket.c:2656)
[ 1584.748063][ T8986]  ? lockdep_hardirqs_on (kernel/locking/lockdep.c:4473)
[ 1584.748067][ T8986]  ? __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)
[ 1584.748072][ T8986]  ? 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)
[ 1584.748074][ T8986]  ? rcu_is_watching (./include/linux/context_tracking.h:128 (discriminator 1) kernel/rcu/tree.c:752 (discriminator 1))
[ 1584.748078][ T8986]  do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1))
[ 1584.748080][ T8986]  ? exc_page_fault (arch/x86/mm/fault.c:1480 (discriminator 3) arch/x86/mm/fault.c:1527 (discriminator 3))
[ 1584.748082][ T8986]  entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[ 1584.748085][ T8986] RIP: 0033:0x7f0fab2c0c5e
[ 1584.748089][ T8986] 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
[ 1584.748090][ T8986] RSP: 002b:00007ffe9e6d40b0 EFLAGS: 00000202 ORIG_RAX: 000000000000002e
[ 1584.748094][ T8986] RAX: ffffffffffffffda RBX: 000000000048a950 RCX: 00007f0fab2c0c5e
[ 1584.748095][ T8986] RDX: 0000000000000000 RSI: 00007ffe9e6d4170 RDI: 0000000000000005
[ 1584.748096][ T8986] RBP: 00007ffe9e6d40c0 R08: 0000000000000000 R09: 0000000000000000
[ 1584.748097][ T8986] R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffe9e6d6895


Finger prints:
fib6_update_sernum:nh_rt_cache_flush:replace_nexthop:insert_nexthop:rtm_new_nexthop