rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4326/1:b..l
	(detected by 1, t=10502 jiffies, g=12297, q=957)
task:kworker/0:11    state:R  running task     stack:25424 pid: 4326 ppid:     2 flags:0x00004000
Workqueue: ipv6_addrconf addrconf_dad_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571
 preempt_schedule+0xbc/0xd0 kernel/sched/core.c:6596
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
 __local_bh_enable_ip+0x147/0x1c0 kernel/softirq.c:408
 rcu_read_unlock_bh include/linux/rcupdate.h:810 [inline]
 ip6_finish_output2+0x111c/0x1530 net/ipv6/ip6_output.c:131
 dst_output include/net/dst.h:452 [inline]
 NF_HOOK+0x163/0x460 include/linux/netfilter.h:302
 mld_sendpack+0x6ee/0xc40 net/ipv6/mcast.c:1825
 ipv6_mc_dad_complete+0x84/0x210 net/ipv6/mcast.c:2252
 addrconf_dad_completed+0x673/0xc80 net/ipv6/addrconf.c:4255
 addrconf_dad_work+0xc83/0x1530 net/ipv6/addrconf.c:-1
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>