rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P8579
	(detected by 0, t=10503 jiffies, g=7121, q=168)
udevd           R  running task    27936  8579   4310 0x0000400a
Call Trace:
 <IRQ>
 sched_show_task+0x40f/0x560 kernel/sched/core.c:5954
 rcu_print_detail_task_stall_rnp kernel/rcu/tree_stall.h:190 [inline]
 print_other_cpu_stall kernel/rcu/tree_stall.h:398 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:538 [inline]
 rcu_pending kernel/rcu/tree.c:2827 [inline]
 rcu_sched_clock_irq+0x16b1/0x1ad0 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:preempt_count arch/x86/include/asm/preempt.h:26 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:153 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0xd/0x50 kernel/kcov.c:187
Code: e5 53 48 89 fb e8 13 00 00 00 48 8b 3d f4 f4 ed 07 48 89 de e8 84 f4 3b 00 5b 5d c3 cc 48 8b 04 24 65 48 8b 0c 25 c0 1d 02 00 <65> 8b 15 38 5f 8b 7e f7 c2 00 01 1f 00 75 2c 8b 91 80 13 00 00 83
RSP: 0018:ffffc90001cf7920 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffffffff814897d3 RBX: 0000000000000000 RCX: ffff888090a041c0
RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea000245dd80
RBP: ffffc90001cf7948 R08: 000000000003a728 R09: fffffbfff124248a
R10: fffffbfff124248a R11: 0000000000000000 R12: dffffc0000000000
R13: dffffc0000000000 R14: 00000000fffffffc R15: ffff8880933799f8
 free_thread_stack+0x168/0x590 kernel/fork.c:280
 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_common kernel/sched/core.c:4236 [inline]
 preempt_schedule+0xdb/0x120 kernel/sched/core.c:4261
 ___preempt_schedule+0x16/0x18 arch/x86/entry/thunk_64.S:50
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
 _raw_spin_unlock_irqrestore+0xcc/0xe0 kernel/locking/spinlock.c:191
 spin_unlock_irqrestore include/linux/spinlock.h:393 [inline]
 __wake_up_common_lock kernel/sched/wait.c:125 [inline]
 __wake_up_sync_key+0xe2/0x150 kernel/sched/wait.c:190
 sock_def_readable+0x162/0x200 net/core/sock.c:2796
 unix_dgram_sendmsg+0x1bd5/0x2690 net/unix/af_unix.c:1762
 sock_sendmsg_nosec net/socket.c:639 [inline]
 sock_sendmsg net/socket.c:659 [inline]
 __sys_sendto+0x442/0x5e0 net/socket.c:1985
 __do_sys_sendto net/socket.c:1997 [inline]
 __se_sys_sendto net/socket.c:1993 [inline]
 __x64_sys_sendto+0xe5/0x100 net/socket.c:1993
 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f187b4f9282
Code: 48 83 c8 ff eb ea 90 90 53 48 83 ec 20 8b 05 81 d3 2a 00 85 c0 75 21 45 31 c9 45 31 c0 4c 63 d1 48 63 ff b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 61 48 83 c4 20 5b c3 48 89 54 24 08 89 0c 24
RSP: 002b:00007ffe618f6700 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00000000013fa130 RCX: 00007f187b4f9282
RDX: 0000000000000008 RSI: 00007ffe618f6750 RDI: 0000000000000009
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000013fbd30 R14: 00000000013fa250 R15: 000000000000000b
rcu: rcu_preempt kthread starved for 10529 jiffies! g7121 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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