=============================
WARNING: suspicious RCU usage
4.14.106+ #30 Not tainted
-----------------------------
net/ipv6/ip6_fib.c:1590 suspicious rcu_dereference_protected() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
6 locks held by kworker/u4:15/7500:
 #0:  ("%s""netns"){+.+.}, at: [<ffffffffa6b289b5>] process_one_work+0x6e5/0x14e0 kernel/workqueue.c:2085
 #1:  (net_cleanup_work){+.+.}, at: [<ffffffffa6b289eb>] process_one_work+0x71b/0x14e0 kernel/workqueue.c:2089
 #2:  (net_mutex){+.+.}, at: [<ffffffffa7cef436>] cleanup_net+0x136/0x860 net/core/net_namespace.c:449
 #3:  (rtnl_mutex){+.+.}, at: [<ffffffffa819cb70>] sit_exit_net+0x80/0x5b0 net/ipv6/sit.c:1868
 #4:  (rcu_read_lock){....}, at: [<ffffffffa80e6690>] __fib6_clean_all+0x0/0x230 net/ipv6/ip6_fib.c:1823
 #5:  (&tb->tb6_lock){++--}, at: [<ffffffffa80e676e>] __fib6_clean_all+0xde/0x230 net/ipv6/ip6_fib.c:1837

stack backtrace:
CPU: 0 PID: 7500 Comm: kworker/u4:15 Not tainted 4.14.106+ #30
Workqueue: netns cleanup_net
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xb9/0x10e lib/dump_stack.c:53
 fib6_del+0x8c2/0xbe0 net/ipv6/ip6_fib.c:1590
 fib6_clean_node+0x270/0x440 net/ipv6/ip6_fib.c:1777
 fib6_walk_continue+0x3a5/0x5f0 net/ipv6/ip6_fib.c:1703
 fib6_walk+0x8d/0xe0 net/ipv6/ip6_fib.c:1748
 fib6_clean_tree+0xd4/0x110 net/ipv6/ip6_fib.c:1822
 __fib6_clean_all+0xf5/0x230 net/ipv6/ip6_fib.c:1838
 rt6_ifdown+0x90/0x5b0 net/ipv6/route.c:2868
 addrconf_ifdown+0xc5/0x13b0 net/ipv6/addrconf.c:3602
netlink: 60 bytes leftover after parsing attributes in process `syz-executor.2'.