[ 1743.502258][T14966] 
[ 1743.502379][T14966] =============================
[ 1743.502516][T14966] WARNING: suspicious RCU usage
[ 1743.502649][T14966] 7.0.0-rc3-virtme #1 Not tainted
[ 1743.502779][T14966] -----------------------------
[ 1743.502906][T14966] net/ipv6/ip6_fib.c:111 suspicious rcu_dereference_protected() usage!
[ 1743.503100][T14966] 
[ 1743.503100][T14966] other info that might help us debug this:
[ 1743.503100][T14966] 
[ 1743.503769][T14966] 
[ 1743.503769][T14966] rcu_scheduler_active = 2, debug_locks = 1
[ 1743.503963][T14966] 1 lock held by ip/14966:
[ 1743.504094][T14966]  #0: ffffffffba0a2728 (rtnl_mutex){+.+.}-{4:4}, at: rtm_new_nexthop+0x1a6/0x8c0
[ 1743.504338][T14966] 
[ 1743.504338][T14966] stack backtrace:
[ 1743.504500][T14966] CPU: 3 UID: 0 PID: 14966 Comm: ip Not tainted 7.0.0-rc3-virtme #1 PREEMPT(full) 
[ 1743.504503][T14966] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 1743.504505][T14966] Call Trace:
[ 1743.504506][T14966]  <TASK>
[ 1743.504508][T14966]  dump_stack_lvl+0x6f/0xa0
[ 1743.504513][T14966]  lockdep_rcu_suspicious.cold+0x4f/0xad
[ 1743.504519][T14966]  fib6_update_sernum+0xfb/0x130
[ 1743.504523][T14966]  nh_rt_cache_flush+0x8d/0x380
[ 1743.504528][T14966]  replace_nexthop+0x347/0x6e0
[ 1743.504532][T14966]  insert_nexthop+0x41e/0x7a0
[ 1743.504536][T14966]  rtm_new_nexthop+0x3a0/0x8c0
[ 1743.504540][T14966]  ? insert_nexthop+0x7a0/0x7a0
[ 1743.504541][T14966]  ? lock_acquire.part.0+0xbc/0x260
[ 1743.504545][T14966]  ? find_held_lock+0x2b/0x80
[ 1743.504551][T14966]  ? lock_acquire.part.0+0xbc/0x260
[ 1743.504552][T14966]  ? find_held_lock+0x2b/0x80
[ 1743.504558][T14966]  ? find_held_lock+0x2b/0x80
[ 1743.504560][T14966]  ? insert_nexthop+0x7a0/0x7a0
[ 1743.504563][T14966]  ? __lock_release.isra.0+0x59/0x170
[ 1743.504566][T14966]  ? insert_nexthop+0x7a0/0x7a0
[ 1743.504568][T14966]  rtnetlink_rcv_msg+0x6fe/0xb90
[ 1743.504573][T14966]  ? rtnl_fdb_dump+0x620/0x620
[ 1743.504575][T14966]  ? __lock_acquire+0x577/0xc10
[ 1743.504579][T14966]  ? lock_acquire.part.0+0xbc/0x260
[ 1743.504580][T14966]  ? find_held_lock+0x2b/0x80
[ 1743.504583][T14966]  netlink_rcv_skb+0x123/0x380
[ 1743.504586][T14966]  ? rtnl_fdb_dump+0x620/0x620
[ 1743.504589][T14966]  ? netlink_ack+0xce0/0xce0
[ 1743.504594][T14966]  ? netlink_deliver_tap+0xc5/0x330
[ 1743.504596][T14966]  ? netlink_deliver_tap+0x13f/0x330
[ 1743.504599][T14966]  netlink_unicast+0x4a3/0x770
[ 1743.504603][T14966]  ? netlink_attachskb+0x810/0x810
[ 1743.504604][T14966]  ? __alloc_skb+0x4c4/0x5f0
[ 1743.504607][T14966]  ? napi_skb_cache_get+0x7a0/0x7a0
[ 1743.504610][T14966]  ? __lock_acquire+0x577/0xc10
[ 1743.504613][T14966]  netlink_sendmsg+0x735/0xc60
[ 1743.504616][T14966]  ? netlink_unicast+0x770/0x770
[ 1743.504619][T14966]  ? __might_fault+0x97/0x140
[ 1743.504625][T14966]  ____sys_sendmsg+0x419/0x850
[ 1743.504628][T14966]  ? copy_msghdr_from_user+0x270/0x430
[ 1743.504630][T14966]  ? get_timestamp.constprop.0+0x390/0x390
[ 1743.504631][T14966]  ? move_addr_to_kernel+0x40/0x40
[ 1743.504635][T14966]  ? lock_acquire.part.0+0xbc/0x260
[ 1743.504636][T14966]  ? find_held_lock+0x2b/0x80
[ 1743.504640][T14966]  ___sys_sendmsg+0xfd/0x180
[ 1743.504642][T14966]  ? copy_msghdr_from_user+0x430/0x430
[ 1743.504644][T14966]  ? __lock_release.isra.0+0x59/0x170
[ 1743.504654][T14966]  ? lock_vma_under_rcu+0x128/0x3e0
[ 1743.504659][T14966]  __sys_sendmsg+0x124/0x1c0
[ 1743.504661][T14966]  ? __sys_sendmsg_sock+0x20/0x20
[ 1743.504667][T14966]  ? do_user_addr_fault+0x799/0xdb0
[ 1743.504670][T14966]  ? rcu_is_watching+0x15/0xd0
[ 1743.504673][T14966]  ? rcu_is_watching+0x15/0xd0
[ 1743.504676][T14966]  do_syscall_64+0x117/0xfc0
[ 1743.504680][T14966]  ? exc_page_fault+0xaf/0xd0
[ 1743.504683][T14966]  entry_SYSCALL_64_after_hwframe+0x4b/0x53
[ 1743.504685][T14966] RIP: 0033:0x7f252bb36c5e
[ 1743.504689][T14966] 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
[ 1743.504691][T14966] RSP: 002b:00007ffe71f525e0 EFLAGS: 00000202 ORIG_RAX: 000000000000002e
[ 1743.504693][T14966] RAX: ffffffffffffffda RBX: 000000000048a950 RCX: 00007f252bb36c5e
[ 1743.504694][T14966] RDX: 0000000000000000 RSI: 00007ffe71f526a0 RDI: 0000000000000005
[ 1743.504695][T14966] RBP: 00007ffe71f525f0 R08: 0000000000000000 R09: 0000000000000000
[ 1743.504696][T14966] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
[ 1743.504697][T14966] R13: 0000000069b9a473 R14: 00000000098c3310 R15: 000000000049c620
[ 1743.504703][T14966]  </TASK>

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