rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=10502 jiffies, g=6989, q=161)
rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4294954609-4294944106), jiffies_till_next_fqs=1, root ->qsmask 0x0
kworker/u4:5    R  running task    31224  8516    286 0x80004008
Call Trace:
 <IRQ>
 sched_show_task+0x40f/0x560 kernel/sched/core.c:5954
 print_other_cpu_stall kernel/rcu/tree_stall.h:410 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:538 [inline]
 rcu_pending kernel/rcu/tree.c:2827 [inline]
 rcu_sched_clock_irq+0x1861/0x1ad0 kernel/rcu/tree.c:2271
 update_process_times+0x12d/0x180 kernel/time/timer.c:1726
 tick_sched_handle kernel/time/tick-sched.c:167 [inline]
 tick_sched_timer+0x263/0x420 kernel/time/tick-sched.c:1310
 __run_hrtimer kernel/time/hrtimer.c:1517 [inline]
 __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1579
 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1641
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline]
 smp_apic_timer_interrupt+0x109/0x280 arch/x86/kernel/apic/apic.c:1135
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 </IRQ>
RIP: 0010:free_thread_stack+0x17f/0x590 kernel/fork.c:284
Code: df e8 55 94 6a 00 48 8b 3b be fc ff ff ff e8 28 04 00 00 43 80 3c 2e 00 74 08 4c 89 e7 e8 39 94 6a 00 49 8b 1c 24 48 83 c3 08 <48> 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 1b 94 6a 00
RSP: 0018:ffffc900021c7e40 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: ffffffff814897d3 RBX: ffff888094987508 RCX: ffff8880a8c62340
RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea000258c3c0
RBP: ffffc900021c7e78 R08: 000000000003a728 R09: ffffed10144e2ac9
R10: ffffed10144e2ac9 R11: 0000000000000000 R12: ffff88809d8fe820
R13: dffffc0000000000 R14: 1ffff11013b1fd04 R15: ffff8880a2715638
 release_task_stack kernel/fork.c:440 [inline]
 put_task_stack+0xa3/0x130 kernel/fork.c:451
 finish_task_switch+0x3f1/0x550 kernel/sched/core.c:3256
 schedule_tail+0x20/0x1a0 kernel/sched/core.c:3320
 ret_from_fork+0x8/0x30 arch/x86/entry/entry_64.S:336
rcu: rcu_preempt kthread starved for 10522 jiffies! g6989 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    29032    10      2 0x80004000
Call Trace:
 context_switch kernel/sched/core.c:3385 [inline]
 __schedule+0x9a0/0xcc0 kernel/sched/core.c:4081
 schedule+0x181/0x210 kernel/sched/core.c:4155
 schedule_timeout+0x14f/0x240 kernel/time/timer.c:1895
 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline]
 rcu_gp_kthread+0xed8/0x1770 kernel/rcu/tree.c:1821
 kthread+0x332/0x350 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352