rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 1, t=10502 jiffies, g=5893, q=163)
rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4294953969-4294943467), jiffies_till_next_fqs=1, root ->qsmask 0x0
udevd           R  running task    27752  7735   4080 0x0000400a
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:1514 [inline]
 __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1576
 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1638
 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+0x195/0x590 kernel/fork.c:284
Code: 2e 00 74 08 4c 89 e7 e8 09 a4 69 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 eb a3 69 00 <48> 8b 1b e9 82 ff ff ff e8 de 2c 2e 00 43 80 3c 2e 00 75 18 eb 1e
RSP: 0018:ffffc90006a97b78 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 1ffff110126e0031 RBX: ffff888093700188 RCX: ffff888096916280
RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea0002a45600
RBP: ffffc90006a97bb0 R08: dffffc0000000000 R09: fffffbfff120248a
R10: fffffbfff120248a R11: 0000000000000000 R12: ffff888093700220
R13: dffffc0000000000 R14: 1ffff110126e0044 R15: ffff8880a8ff79e8
 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
 context_switch kernel/sched/core.c:3388 [inline]
 __schedule+0x9a8/0xcc0 kernel/sched/core.c:4081
 preempt_schedule_irq+0xc1/0x140 kernel/sched/core.c:4338
 retint_kernel+0x1b/0x2b
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:752 [inline]
RIP: 0010:slab_alloc mm/slab.c:3313 [inline]
RIP: 0010:kmem_cache_alloc+0x1a8/0x2e0 mm/slab.c:3484
Code: 8b 7d d0 57 9d 0f 1f 44 00 00 e8 83 b1 ca ff eb 1e e8 1c af ca ff 48 83 3d 7c 10 59 07 00 0f 84 33 01 00 00 48 8b 7d d0 57 9d <0f> 1f 44 00 00 41 0f 18 0e e9 21 00 00 00 89 d8 c1 e8 08 83 e0 01
RSP: 0018:ffffc90006a97dc8 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: ffff888096916b14 RBX: 0000000000000cc0 RCX: ffff888096916280
RDX: 0000000000000000 RSI: ffffffff81be59ca RDI: 0000000000000286
RBP: ffffc90006a97e00 R08: ffff888096916ad8 R09: ffffed101553fdc1
R10: ffffed101553fdc1 R11: 0000000000000000 R12: ffff8880aa9faa80
R13: ffff8880aa9faa80 R14: ffff88806c200a40 R15: 0000000000000cc0
 getname_flags+0xba/0x640 fs/namei.c:138
 getname+0x19/0x20 fs/namei.c:209
 do_sys_open+0x261/0x560 fs/open.c:1091
 __do_sys_open fs/open.c:1115 [inline]
 __se_sys_open fs/open.c:1110 [inline]
 __x64_sys_open+0x87/0x90 fs/open.c:1110
 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fb4944ff120
Code: 48 8b 15 1b 4d 2b 00 f7 d8 64 89 02 83 c8 ff c3 90 90 90 90 90 90 90 90 90 90 83 3d d5 a4 2b 00 00 75 10 b8 02 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 5e 8c 01 00 48 89 04 24
RSP: 002b:00007ffc5369da08 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 000000000185f650 RCX: 00007fb4944ff120
RDX: 00000000000001b6 RSI: 0000000000080000 RDI: 00007ffc5369dae0
RBP: 00007ffc5369da80 R08: 0000000000000008 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000008
R13: 000000000041f57a R14: 0000000000000000 R15: 000000000000000b
rcu: rcu_preempt kthread starved for 10502 jiffies! g5893 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    29104    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