ipset: suspicious RCU usage

ipset: suspicious RCU usage

[Dave Jones]

=============================
WARNING: suspicious RCU usage
4.16.0-rc3-firewall+ #1 Not tainted
-----------------------------
net/netfilter/ipset/ip_set_core.c:1354 suspicious rcu_dereference_protected() usage!
\x0aother info that might help us debug this:\x0a
\x0arcu_scheduler_active = 2, debug_locks = 1
2 locks held by ipset/16323:
 #0: nlk_cb_mutex-NETFILTER ){+.+.} , at: [<000000005e54683c>] netlink_dump+0x1c/0x2b0
 #1: (ip_set_ref_lock){++..} , at: [<0000000089f25f26>] ip_set_dump_start+0x133/0x7a0

stack backtrace:
CPU: 0 PID: 16323 Comm: ipset Not tainted 4.16.0-rc3-firewall+ #1 
Call Trace:
 dump_stack+0x67/0x8e
 ip_set_dump_start+0x5f0/0x7a0
 ? ip_set_dump_start+0x5/0x7a0
 ? __kmalloc_reserve.isra.38+0x29/0x70
 ? ksize+0x10/0xa0
 ? __alloc_skb+0x90/0x1b0
 netlink_dump+0x106/0x2b0
 netlink_recvmsg+0x337/0x380
 ? copy_msghdr_from_user+0xdb/0x150
 ___sys_recvmsg+0xc6/0x160
 ? netlink_sendmsg+0x129/0x420
 ? SYSC_sendto+0x11b/0x180
 __sys_recvmsg+0x51/0x90
 do_syscall_64+0x84/0x735
 ? trace_hardirqs_off_thunk+0x1a/0x1c
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7fa78e00ca57
RSP: 002b:00007fff61cfad78 EFLAGS: 00000246
ORIG_RAX: 000000000000002f
RAX: ffffffffffffffda RBX: 000055f22c7c06f0 RCX: 00007fa78e00ca57
RDX: 0000000000000000 RSI: 00007fff61cfada0 RDI: 0000000000000003
RBP: 000055f22c7bf4b8 R08: 00007fa78dd1fbe0 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000001000
R13: 000055f22c7c04d0 R14: 0000000000000000 R15: 000055f22bf13908