[ 1064.154947][T15458] 
[ 1064.155074][T15458] =============================
[ 1064.155215][T15458] WARNING: suspicious RCU usage
[ 1064.155347][T15458] 7.0.0-rc1-virtme #1 Not tainted
[ 1064.155476][T15458] -----------------------------
[ 1064.155603][T15458] net/ipv6/ip6_fib.c:111 suspicious rcu_dereference_protected() usage!
[ 1064.155789][T15458] 
[ 1064.155789][T15458] other info that might help us debug this:
[ 1064.155789][T15458] 
[ 1064.156052][T15458] 
[ 1064.156052][T15458] rcu_scheduler_active = 2, debug_locks = 1
[ 1064.156247][T15458] 1 lock held by ip/15458:
[ 1064.156378][T15458]  #0: ffffffffbb67e6e8 (rtnl_mutex){+.+.}-{4:4}, at: rtm_new_nexthop+0x1a6/0x8c0
[ 1064.156612][T15458] 
[ 1064.156612][T15458] stack backtrace:
[ 1064.156771][T15458] CPU: 0 UID: 0 PID: 15458 Comm: ip Not tainted 7.0.0-rc1-virtme #1 PREEMPT(full) 
[ 1064.156774][T15458] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 1064.156775][T15458] Call Trace:
[ 1064.156777][T15458]  <TASK>
[ 1064.156779][T15458]  dump_stack_lvl+0x6f/0xa0
[ 1064.156785][T15458]  lockdep_rcu_suspicious.cold+0x4f/0xad
[ 1064.156791][T15458]  fib6_update_sernum+0xfb/0x130
[ 1064.156795][T15458]  nh_rt_cache_flush+0x8d/0x380
[ 1064.156799][T15458]  replace_nexthop+0x347/0x6e0
[ 1064.156804][T15458]  insert_nexthop+0x41e/0x7a0
[ 1064.156808][T15458]  rtm_new_nexthop+0x3a0/0x8c0
[ 1064.156811][T15458]  ? insert_nexthop+0x7a0/0x7a0
[ 1064.156813][T15458]  ? lock_acquire.part.0+0xbc/0x260
[ 1064.156816][T15458]  ? find_held_lock+0x2b/0x80
[ 1064.156822][T15458]  ? lock_acquire.part.0+0xbc/0x260
[ 1064.156823][T15458]  ? find_held_lock+0x2b/0x80
[ 1064.156829][T15458]  ? find_held_lock+0x2b/0x80
[ 1064.156830][T15458]  ? insert_nexthop+0x7a0/0x7a0
[ 1064.156832][T15458]  ? __lock_release.isra.0+0x59/0x170
[ 1064.156836][T15458]  ? insert_nexthop+0x7a0/0x7a0
[ 1064.156838][T15458]  rtnetlink_rcv_msg+0x6fe/0xb90
[ 1064.156843][T15458]  ? rtnl_fdb_dump+0x620/0x620
[ 1064.156845][T15458]  ? __lock_acquire+0x577/0xc10
[ 1064.156849][T15458]  ? lock_acquire.part.0+0xbc/0x260
[ 1064.156851][T15458]  ? find_held_lock+0x2b/0x80
[ 1064.156855][T15458]  netlink_rcv_skb+0x123/0x380
[ 1064.156860][T15458]  ? rtnl_fdb_dump+0x620/0x620
[ 1064.156865][T15458]  ? netlink_ack+0xcc0/0xcc0
[ 1064.156871][T15458]  ? netlink_deliver_tap+0xc5/0x330
[ 1064.156873][T15458]  ? netlink_deliver_tap+0x13f/0x330
[ 1064.156877][T15458]  netlink_unicast+0x4a3/0x770
[ 1064.156881][T15458]  ? netlink_attachskb+0x810/0x810
[ 1064.156883][T15458]  ? __alloc_skb+0x4cd/0x600
[ 1064.156886][T15458]  ? napi_skb_cache_get+0x7a0/0x7a0
[ 1064.156889][T15458]  ? __lock_acquire+0x577/0xc10
[ 1064.156893][T15458]  netlink_sendmsg+0x735/0xc60
[ 1064.156897][T15458]  ? netlink_unicast+0x770/0x770
[ 1064.156901][T15458]  ? __might_fault+0x97/0x140
[ 1064.156906][T15458]  ____sys_sendmsg+0x419/0x850
[ 1064.156909][T15458]  ? copy_msghdr_from_user+0x270/0x430
[ 1064.156911][T15458]  ? get_timestamp.constprop.0+0x3a0/0x3a0
[ 1064.156912][T15458]  ? move_addr_to_kernel+0x40/0x40
[ 1064.156916][T15458]  ? lock_acquire.part.0+0xbc/0x260
[ 1064.156918][T15458]  ? find_held_lock+0x2b/0x80
[ 1064.156921][T15458]  ___sys_sendmsg+0xfd/0x180
[ 1064.156923][T15458]  ? copy_msghdr_from_user+0x430/0x430
[ 1064.156924][T15458]  ? __lock_release.isra.0+0x59/0x170
[ 1064.156935][T15458]  ? lock_vma_under_rcu+0x128/0x3e0
[ 1064.156940][T15458]  __sys_sendmsg+0x124/0x1c0
[ 1064.156943][T15458]  ? __sys_sendmsg_sock+0x20/0x20
[ 1064.156948][T15458]  ? do_user_addr_fault+0x799/0xdb0
[ 1064.156954][T15458]  ? rcu_is_watching+0x15/0xd0
[ 1064.156958][T15458]  ? rcu_is_watching+0x15/0xd0
[ 1064.156961][T15458]  do_syscall_64+0x117/0xfc0
[ 1064.156966][T15458]  ? exc_page_fault+0xaf/0xd0
[ 1064.156969][T15458]  entry_SYSCALL_64_after_hwframe+0x4b/0x53
[ 1064.156971][T15458] RIP: 0033:0x7f2241ad9c5e
[ 1064.156975][T15458] 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
[ 1064.156977][T15458] RSP: 002b:00007ffe4d3c9e40 EFLAGS: 00000202 ORIG_RAX: 000000000000002e
[ 1064.156980][T15458] RAX: ffffffffffffffda RBX: 000000000048a910 RCX: 00007f2241ad9c5e
[ 1064.156981][T15458] RDX: 0000000000000000 RSI: 00007ffe4d3c9f00 RDI: 0000000000000005
[ 1064.156982][T15458] RBP: 00007ffe4d3c9e50 R08: 0000000000000000 R09: 0000000000000000
[ 1064.156983][T15458] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
[ 1064.156984][T15458] R13: 0000000069a4851a R14: 000000003dbd8310 R15: 000000000049b620
[ 1064.156990][T15458]  </TASK>